insight into the endogenous and exogenous modes of pigmentation in the oral cavity

1. P R E S E N T E D B Y
K . N AV I N N A I R
J U N I O R R E S I D E N T
PIGMENTED LESIONS
OF THE ORAL CAVITY

2. CONTENTS – PART A
1. PHYSIOLOGY OF MELANOCYTES
2. MELANOGENESIS
3. MELANOTIC MACULE
4. ORAL MELANOACANTHOMA
5. MALIGNANT MELANOMA

3. INTRODUCTION
• Pigmentation is defined as the process of deposition of
pigments in tissues.
• Change in colour of oral mucosa reflects the underlying health
status, which may be either local or systemic.
• This colour change is due to pigmentation, which may be
physiological or pathological.
• Pigmentation in pathological conditions range from localized
anomalies to potentially life-threatening conditions.

4. CLASSIFICATION
• Oral pigmentation may be physiologic or pathologic.
• Pathologic pigmentation can be classified into exogenous and
endogenous based upon the cause.
• Exogenous pigmentation could be induced by drugs,
tobacco/smoking, amalgam tattoo or heavy metals .
• Endogenous pigmentation can be associated with endocrine
disorders, syndromes, infections, chronic irritation, reactive or
neoplastic

6. ENDOGENOUS PIGMENTATION

7. EXOGENOUS PIGMENTATION

8. PHYSIOLOGY OF PIGMENTATION
• There are four pigments which contribute to the normal
color of the skin and mucosa -
Melanin
Carotenoids
Reduced HB
Oxygenated HB.

9. 1. ORIGIN
2. STRUCTURE
3. KERATINOCYTE-MELANOCYTE UNIT
4. FUNCTION
5. MELANOGENESIS
6. CYTOCRINE THEORY

10. MELANIN
• Melanin is an endogenous non-hematogenous pigment.
• It is produced by melanocytes in the basal layer of the
epithelium and is transferred to adjacent keratinocytes via
membrane bound organelles called melanosomes.
• It is also synthesized by nevus cells, which are neural crest
derivatives and are found in the oral mucosa and skin.
• Depending on the location and amount of melanin in the
tissues, melanin induced pigmentation can be either black,
gray, blue or brown in colour.

11. THE ORIGIN OF MELANOCYTES
• Melanocytes are melanin producing cells originating from
the neural crest.
• During development melanocyte stem cells migrate from
the neural crest to the skin and to mucous membranes.
• Melanocyte stem cells have the capacity for self renewal
and for differentiation and thus can maintain the
population of mature melanocytes.

13. • Active melanocytes are present in
1. the stria vascularis of the cochlea,
2. in the leptomeninges,
3. in the substantia nigra and locus coerulus of the brain,
and
4. in the heart,
• where they play a number of as yet ill defined roles

14. • In the epidermis, the melanocyte stem cells reside in the bulge
region of hair follicles , but the niche in which they reside in the
oral mucosa is unknown.
• Stem cell factor (SCF) and its tyrosine kinase receptor C-kit
signalling pathways are critical for epidermal melanocyte
development during embryogenesis.
• notch signalling pathways are essential in the maintenance of
adult melanocyte stem cells, and thus for melanocyte
homeostasis
• endothelin 1 plays a role in the differentiation of melanocyte
precursors
• Micropthalmia associated transcription factor (MITF) with its
cAMP response element play a critical role in melanogenesis

15. • In the skin, migration of precursor melanocytes from the
dermis to their final destination in the basal cell layer of
the epithelium is mediated by c-Kit/ SCF, endothelin 1
and 3, hepatocyte growth factor (HGF) and basic
fibroblast growth factor (bFGF).
• These precursor dermal melanocytes, as they pass
through the basement membrane, express E cadherin
which later facilitates intercellular communication with
neighbouring keratinocytes in the basal cell layer of the
epithelium.
• melanocyte precursors on their way to the epithelium
may become arrested in the lamina propria/dermis, and
as they have the capacity to produce melanin, if they are
aggregated they will form nevi.

16. THE KERATINOCYTE MELANOCYTE
UNIT
• Mature melanocytes are elongated dendritic cells residing
in the basal cell layer of the epithelium.
• In the basal cell layer of the epithelium the ratio of
melanocytes to keratinocytes ranges from 1:10 to 1:15.
• Melanocytes and keratinocytes form epidermal melanin
units, each unit consists of one melanocyte and a group
of about 36 neighbouring keratinocytes.

17. • The melanosomes produced by melanocytes are
disseminated via a network of melanocytic dendritic
processes to the keratinocytes of the epidermal melanin
unit.
• It has been suggested that through biological mediators
present in the melanosomes transferred to keratinocytes,
melanocytes can influence the functional activities of
keratinocytes ,
• keratinocytes via an array of paracrine like biological
mediators, that they secrete, have the capacity to
regulate melanogenesis

18. • The adherence of melanocytes to keratinocytes is by means
of tight junctions where they co-express E- cadherin cell
adhesion molecules.
• E-cadherin supresses melanocyte proliferation, but a switch
from E-cadherin to N-cadherin owing to metabolically or
traumatically triggered events in the microenvironment obviate
the melanocytes from growth suppression.
• Melanocytes expressing N-cadherin can freely proliferate,
migrate and self aggregate in nests, and exhibit longevity

21. THE FUNCTION OF ORAL
MELANOCYTES
• The functions of melanocytes are not fully understood.
• melanin determines the colour of skin, hair and eyes.
• provides protection from stressors such as UV radiation,
reactive oxygen species (ROS) and free radicals in the
environment.
• Melanins also have the capacity to sequester metal ions and
to bind certain drugs and organic molecules

22. • melanin possesses both antioxidant and ROS dependent
cytotoxic properties.
• Quinones and semiquinones which are intermediates of
melanogenesis are toxic or mutagenic with the potential
to cause cytogenetic instability.
• L-dopa has the capacity to inhibit the production of pro-
inflammatory cytokines by T lymphocytes and
monocytes, thus down regulating immune and
inflammatory responses.

23. • Melanins produced by melanocytes residing in the basal cell
layer of the gingival epithelium have the capacity to neutralize
ROS generated by dento-gingival plaque induced
inflammation in the periodontal microenvironment.
• Melanosomes contain lysosomal enzymes including α-
mannosidase, acid phosphatase, β-N-acetylglycosaminidase,
β-galactosidase, and acid lipase that can degrade bacteria.
• Melanin itself can neutralise bacteria derived enzymes and
toxins, and since it has strong binding properties, it can also
act as a physical barrier against microorganisms.
• melanocytes can act as antigen presenting cells, can
stimulate T cell proliferation, and can phagocytose
microorganisms

24. • As keratinocytes ascend through the cell layers of the
epithelium and are shed, their melanosomal membranes
undergo degradation with release of melanin ‘dust’ which
becomes entangled in the keratin filaments of the
desquamating surface cells.
• This melanin dust inactivates pathogenic chemicals,
microbial toxins and other biologically active molecules.

25. • Melanocytes in skin, and perhaps in oral mucosa
express genes encoding –
1. corticotropin releasing factor (CRF),
2. proopiomelanocortin (POMC),
3. ACTH,
4. β endorphins,
5. α-MSH and
6. melanocortin1 receptor (MC1R).
• These elements of the skin melanocortin system have
the capacity to neutralize external noxious agents, to
mediate local antimicrobial and immune responses, and
to mediate local nociception

26. MELANOGENESIS
• Melanogenesis comprises a process of oxidation of the
amino acid tyrosine and derived aromatic compounds,
forming two main types of polymeric phenolic
compounds.
1. Large, irregular granules of eumelanin which are black
brown in colour.
2. smaller, more regular granules of pheomelanin which
are yellow red in colour

30. • The melanocortin system through the cAMP/MITF
pathway can stimulate proliferation of undifferentiated
melanocytes, their maturation with fully formed dendritic
processes, and up regulation of melanogenesis, thus
increasing the formation of melanin.
• α-MSH has the capacity to suppress inflammatory
responses, because it can inhibit nuclear factor κ
B(NFκB) that regulates the expression of genes of pro-
inflammatory cytokines.

31. • Epidermal melanocytes express α1and β 2-
adrenoceptors, the activation of which leads to an
increase in melanin biosynthesis and a concurrent
increase in the number and complexity of melanocytic
dendrites.
• The adrenalin/β2 adrenoceptor/cAMP/MITF pathway like
the α-MSH/MC1R/cAMP/MITF pathway has therefore
the capacity to mediate melanin production and its
dendritic distribution.

32. • The β-endorphin/μ-opioid receptor signalling pathway is
expressed and functionally active, mediating
differentiation and maturation of melanocytes with
increased melanogenesis.
• Mediators of inflammation such as histamine and
arachidonic acid metabolites trigger melanogenesis
• inflammatory cytokines such as TNFα and IL1α induce
the secretion of melanogenic agents (SCF, HGF, bFGF,
endothelins) by keratinocytes.
• Together these agents account for the melanin
pigmentation sometimes observed in association with
inflammatory conditions of skin or oral mucosa

33. THE CYTOCRINE THEORY OF MELANIN
PIGMENTATION
• Masson (1948) gave “cytocrine” theory of melanin
secretion.
• According to this theory melanin is present in specialized
pigment producing cells called as melanocytes, which
got transferred in granular form into neighboring
epidermal cells.

34. PHYSIOLOGICAL ORAL PIGMENTATION
• More common in dark skinned individuals irrespective of
ethnicity.
• Microscopically, there is increased melanin in the basal
cell layer and sometimes in the upper portion of lamina
propria within melanophages..

35. MELANOTIC MACULE
• It is a unique, benign pigmented lesion that has no
known dermal counterpart.
• Most common oral lesions of melanocytic origin.
• Etiology is unknown
• Trauma is postulated to play a role.

36. • F>M
• May develop at any age. Common in adulthood.
• Lower lip > gingiva > tongue
• Tend to be small and does not enlarge after a certain
size.
• Does not recur following surgery.

38. • MICROSCOPY – characterised by normal epithelial
layer, with basal cells containing an abundance of
melanin pigment coupled with increase in the number of
melanocytes.
• DD – melanocytic nevus, malignant melanoma,
amalgam tattoo and focal ecchymosis
• Biopsy of any persistent solitary pigmented lesion is
always warranted.

39. ORAL MELANOACANTHOMA
• Benign, melanocytic lesion unique to mucosal tissues.
• Usually reactive in nature.
• Rapidly enlarging, ill-defined, darkly pigmented macular
or plaque like lesion
• F>M, 3rd and 4th decades
• Buccal mucosa is the most common site.

42. • MICROSCOPY – characterised by a proliferation of
benign, dendritic melanocytes throughout the full
thickness of an acanthotic and spongiotic epithelium.
• DD – malignant melanoma, nevus and melanotic
macule.

43. MALIGNANT MELANOMA
• Malignant melanoma (MM) is a malignancy of pigment
producing cells (melanocytes), which are located primarily in
the skin, but also found in the ears, gastrointestinal tract,
eyes, oral and genital mucosa and leptomeninges.
• The sequence of events whereby normal melanocytes
transform into melanoma cells is not fully understood.
• It is most likely due to a multistep process of genetic
mutations that alter the cell cycle and render the melanocytes
more susceptible to the carcinogenic effects of UVR.

44. MOLECULAR PATHOLOGY OF
MELANAOMA
1. Overview
2. Factors involved
3. Antigenic profile
4. Genomics
5. Diagnosis

45. MOLECULAR PATHOLOGY
• Melanocytes derive from the neural crest during
embryonal development; cells from this area migrate to
the skin in a pathway marked and modified by
mesenchyme.
• Epidermal melanocytes are normally mitotically inactive
but can proliferate briefly after selected external signals,
such as UV radiation.
• Hair follicle melanocytes express, in contrast, cyclic
proliferative and melanogenic activity coupled to the
growing phase of hair

46. • Cutaneous melanomas are derived from epidermal
melanocytes or dermal nevo-melanocytes.
• Melanomas have been shown to produce several growth
factors and cytokines and to express their receptors, including
1. keratinocyte growth factor (KGF),
2. platelet-derived growth
3. factors a and B scatter factor (SCF),
4. melanoma growth-stimulating activity/gro,
5. interleukin (IL)-la, IL-ip, IL-6, IL-7,
6. IL-8, IL-10, IL-12,
7. granulocyte-macrophage colony-stimulating factor,
8. granulocyte colony-stimulating factor,
9. Tumour necrosis factor (TNF)
10. a, interferon (INF)-y, and INF-B.

47. • These factors can act as regulators of melanoma cell
proliferation, differentiation, and motility.
• can stimulate angiogenesis
• regulate expression of major histocompatibility antigens, cell
adhesion molecules, integrins, non-integrin matrix adhesion
receptors, and extracellular matrix proteins on melanocytes
and on surrounding cells.
• Basic fibroblast growth factor has a central role as growth
regulator of normal melanocytes.
• The role of insulin-like growth factors (IGFs), insulin, and their
receptors in the regulation of melanoma growth has been
suggested since insulin can stimulate or inhibit the growth of
melanoma cells in vivo and in vitro.

48. ANTIGENIC PROFILE
• is distinctive according to stages of progression.
• increased expression of TGF-B, IGF-I, and the receptor
for EGF (EGFR) seems to correlate with increased depth
of invasion and higher frequency of metastases in
malignant melanoma.
• The expression of B-human chorionic gonadotropin
messenger RNA (mRNA) may serve as a marker for
cutaneous melanoma.

49. CYTOGENETICS
• DNA ploidy may be of prognostic value for the course of
malignant melanoma.
• Melanocytic lesions with little or no cytologic atypia tend to be
euploid, while those with high-grade atypia are most
commonly aneuploid.
• metastases also express significantly higher aneuploidy than
does the primary tumour.
• When measured by tissue section image analysis, DNA
aneuploidy has correlated with disease progression in
intermediate-thickness level III melanomas, while diploid
tumors have followed a benign course similar to thin, early
stage cases.

50. • Malignant melanomas are characterized by highly
aneuploid karyotype with multiple chromosomal
aberrations.
• Non random karyotypic abnormalities of chromosomes
1,6,7,9,10, and 11 seem to be associated with increasing
aggressiveness of melanoma.
• Chromosome 6 abnormalities are frequent in melanoma
and have not been described in benign or dysplastic
nevi.
• The most common changes were nonreciprocal
translocations or deletions involving the 6ql l-6q24.

51. • By using the techniques of FISH and PCR amplification
protocols after tissue micro-dissection, it has been
shown that loss of chromosomes l, 33, 16, 17, and 22
occurs in radial growth phase (RGP) and vertical growth
phase (VGP), suggesting that VGP cells may be derived
from the RGP.

52. TUMOUR SUPPRESSOR GENE
• The tumor suppressor gene pl6INK4, maps to chromosome
9pl3-22 containing putative locus of familial melanoma.
• P16INK4 binds to the cataiytic subunit of CDK4 or CDK6,
inhibiting the kinase activity of CDK4-cyclin D and CDK6-
cyclin D kinase activity and acts as a negative regulator of cell
cycle progression.
• pl6INK4 and CDK4 proteins showed that overexpression of
CDK4 was characteristic for malignant melanoma, while the
expression of pl6INK4 in malignant melanoma was lower than
that in benign nevi.
• Other genes coding proteins regulating the cell cycle and
potentially involved in melanocyte transformation include
pl5INK4B, pl8, pl9, and p21.

53. DIFFERENTIATION MARKERS OF
MELANOMA
• Markers widely used in immunocytochemical diagnostic
pathology are S-100 and HMB-45 antigens.
• The S-100 antigen is not specific because it also is
expressed in other neuroectodermal cells and in
Langerhans cells.
• the HMB-45 antigen is more specific, since it is localized
in the premelanosomes and melanosomes of normal and
malignant melanocytes.

54. IMMUNE MARKERS OF MELANOMA
• decrease in the expression of HLA class I molecules or
changes in HLA-I specific subclasses may be associated with
progression of melanoma.
• Within HLA class II molecules that activate CD4+
lymphocytes, it has been reported that the expression of the
HLA-DR and HLA DP on melanoma cells increases with the
progression from the radial growth phase to the vertical and
metastatic growth phase.
• Immunization protocols for the systemic treatment of
melanoma are being developed that use recombinant viruses
and bacteria, naked DNA containing tumor antigen genes,
and genetically modified cells expressing or presenting tumor
antigen

55. TYPES
• LENTIGO MALIGNA MELANOMA presents as a
slowing growing or changing patch of discoloured skin
with variegated shape and colour.

56. • A NODULAR MELANOMA may present as a rapidly
enlarging lump (weeks to months).
• One third of nodular melanomas are amelanotic i.e. non-
pigmented and may be ulcerated.
• any new ulcerated nodular skin lesion should alert the
clinician to the high possibility of skin cancer.

57. • ACRAL LENTIGINOUS MELANOMA starts as a slowly
enlarging flat patch of discoloured skin and tends to
follow the ABCDE rule.

58. ABCDE

59. RADIAL VS VERTICAL GROWTH PHASE

61. MANAGEMENT
• Ablative surgery with wide margins is treatment of
choice.
• Newer techniques include the administration of
cytokines, such as IL-2, IL-10, IL-12, and INF-y, that
would augment immunization of tumor recognition or
delivery of recombinant DNA containing cytokine or HLA
and B7 molecule genes into the tumor

63. • THANK YOU

64. REFERENCES
1. Pathologic basis of disease – Robbins and Cotran
2. Shafer’s textbook of oral pathology
3. Melanin: the biophysiology of oral melanocytes – Feller,
Masilana, Khammissa
4. Molecular pathology of malignant melanoma – Slominski,
Wortsman, Nickoloff
5. Burkett’s Textbook of Oral Medicine
6. Internet sources.

65. PR ESEN TED BY
D R .K.N AVIN N AIR
PIGMENTED LESION S OF
ORAL CAVITY – 2
MELANIN DISORDERS

66. • HOW IS A MELANOSOME TAKEN UP BY
KERATINOCYTE??
Melanosomes are acquired by keratinocytes through a
heterophagic process whereby they phagocytize bits of the
melanosome-laden dendrites of the melanocytes
The molecular mechanisms of the melanosomes transfer from
melanocyte to keratinocytes is still a subject of investigations.
Ando et al. proposed a model of melanosomes’ transport via
the shedding vesicle system through the following stages-

68. • the membrane pigment globules (PG) containing multiple
melanosomes and a few mitochondria are formed in the filopodia of
melanocyte dendrites,
• PG are released from different areas of the dendrites into
extracellular space,
• PG are captured by microvilli of keratinocytes, which incorporate
them in a protease-activated receptor-2 (PAR-2)-dependent way,
• membrane-surrounded PG is degraded,
• single melanosomes are released in a keratinocyte cytosol and reach
the perinuclear area.

69. • FATE OF MELANOSOME IN KERATINOCYTE ??
- is significantly influenced by the size of the individual
melanosomes.
- melanosomes which exceed approximately 0.8mic in
greatest diameter will be distributed singly within
membrane-limited vesicles of the keratinocytes.
- Melanosomes less than approximately 0.8mic in greatest
diameter will be aggregated in groups of two or more to
each membrane limited vesicle.

70. • Meaning of acral lentiginous ??
• - acral means : relating to or affecting the peripheral
parts
• - lentigines means : small pigmented spot on skin with a
clearly defined edge

71. CONTENTS
• COMMON TERMINOLOGY
• EPHELIS
• MELANOCYTIC NEVUS
• MELASMA

72. COMMON TERMINOLOGY
• Developmental defects are errors in morphogenesis
arising during intrauterine life.
• A malformation is a primary anatomical defect resulting
from abnormal development of an organ or tissue.
• A malformation syndrome is the occurrence of multiple
malformations in a recognizable pattern, frequently
accompanied by mental retardation, for example Down’s
syndrome.

73. • A malformation sequence occurs when a primary
malformation produces secondary defects, for example
hydrocephalus secondary to spina bifida.
• Deformation reflects abnormal intrauterine moulding by
mechanical forces, for example positional deformation of
the legs and feet in spina bifida.
• Disruption indicates intrauterine damage or destruction
to a developed organ by agents such as infection.

74. FRECKLE/EPHELIS
• Ephelides are small, well circumscibed pigmented
macules found only on sun exposed skin.
• Are not seen at birth but appear a few years later.
• Autosomal mode of inheritance is suspected.
• Incidence reduces with age
• Histologically – the keratinocytes show an increase in
content, esp in basal layer.

76. MELANOCYTIC NAEVUS
• Naevus is the Latin word for ‘maternal impression’ or
‘birthmark’
• A circumscribed, non-neoplastic skin or mucosal lesion,
usually present at or soon after birth and fixed.
• Melanocytic naevi are normal, benign proliferations of
melanocytes.
• melanocytic naevi are both risk factors for melanoma and
precursors of melanoma.

77. ETIOLOGY
• Genetic mosaicism resulting from somatic mutation is
probably the major cause of naevi.
• During early embryogenesis a mutation gives rise to a
clone of cells in which the genetic change manifests as a
localized cutaneous abnormality.
• Familial clustering of mosaic conditions may be due to a
unstable mutation
• Happle has suggested two mechanisms to explain
familial clustering of mosaic conditions -

78. • paradominant inheritance
• silencing and activation of different genes by
transposable elements

79. CLASSIFI CATION OF NAEVI
• according to the component cell, tissue or organ,
• subdivided according to the macroscopic or histological
nature of the abnormality
• Broad division groups -
1. Epidermal nevi
2. Dermal and subcutaneous nevi

80. EPIDERMAL NEVI
• Keratinocyte naevi
• Sebaceous naevi
• Follicular naevi
• Apocrine naevi
• Eccrine naevi
• Inflammatory epidermal naevi
• Epidermal naevus syndrome

81. DERMAL AND SUBCUTANEOUS NAEVI
• Connective tissue naevi – collagen naevi , elastic naevi,
proteoglycan naevi,
• Muscle naevi
• Fat naevi

82. • ACCORDING TO ORIGIN (Hansen and Buchner)
a. Developmental –
- epidermal nevus
- nevus sebaceus
- basal cell nevus
- nevus flammeus
- white sponge nevus

83. B. Acquired – based on evolution of clinical stages and
histopathologic features -
- junctional nevus
- compound nevus
- intradermal/intramucosal nevus

84. BLASCHKO’S LINES
• Almost all epidermal naevi follow the pattern of lines
• Blaschko’s lines are characteristic of mosaic conditions of the
epidermis
• May represent the routes of ectodermal cell migration from
the neural crest
• S-shaped wave form on the lateral trunk
• V-shape in the middle of the back
• On arms and legs, lines are roughly parallel with the axis of
the limb.

86. ACQUIRED NEVI
• Benign, localized proliferation of cells from the neural
crest.
• Lesions develop usually before 35years of age
• F>M, Whites > Blacks/asians
• Lesions seen usually above the waist

87. PATHOPHYSIOLOGY/NEVOGENSIS
• Concept of abtropfung by Unna(1893)
• melanocytic nevus cells develop in the epidermis, then
"drop off" into the dermis over time
• Now, it is used as a
Simple mechanistic model
To explain localisation of
Nevus cells in histologic
Layers

88. • MASSON CONCEPT (1951)
• Proposed a dual origin of nevus cells –
1. From epidermic melanoblasts
2. From schwann cells
• Later this concept was disproved.

89. • MISHIMA 1965 –
• Introduced the nevoblast – a differential state in which
the neural crest derived precursor cells are already
committed to become nevus cells
• However, like masson , this concept also believed in
schwannian lineage for nevus cells deep in the dermis

90. • HOCHSTEIGERUNG concept –(1984)
- during ontogenesis, neural crest derived precursor
cells reach the skin via cutaneous nerves extending from
paraspinal ganglia.
- recurrent nevi following incomplete surgical
removal

91. • DEVELOPMENT OF ACQUIRED NEVI
- Increased melanocyte production
- Generation of additional keratinocytes
- Capacity of epidermis to respond is exceeded
- Accumulation of junctional melanocytes in nests
- Continued proliferation leading to nevus cells in large
numbers

92. ABTROPFUNG DUAL ORIGIN HOCHSTEIGERUNG

93. PROTEOME OF NEVUS CELLS
• Culturing of nevus cells, even from purely dermal parts,
leads to a dendritic phenotype morphologically
indistinguishable from cultured melanocytes.
• Thus, nevus cells are mostly regarded as a
differentiational state of melanocytes.

94. GENOMICS OF NEVUS CELLS
• the responsible genes have not yet been identified.
• genetic linkage to mutations of the p16-gene (CDKN2A)
on chromosome 9p21
• high frequency of activating BRAF mutations in nevi
indicates a possible role of this intracellular signaling
kinase in nevogenesis
• The pre- disposition to develop high nevus counts most
probably represents a polygenic trait.

95. Do the cells develop from dermal precursor cells, thus
more or less independent from UV(B) light?
- The role of sunlight in the development of nevi remains
poorly characterized on the molecular level.
- Solar irradiation leads to increased melanin production
and slightly increased melanocyte proliferation.
- In melanocytes and keratinocytes, it induces reactive
oxygen species and direct DNA damage

96. • The histologic spectrum of melanocytic nevi, comprises
of the classic, ‘‘nest-forming’’ nevus.
• Nest-forming nevus cells stay in direct contact with each
other.
• nests are surrounded by a basement membrane
containing laminin and type IV collagen
• UV light stimulates the production of epidermal
cytokines, growth factors, and neuropeptides.
• E-cadherin is down- regulated by UV-induction of
keratinocyte endothelin-1 possibly affecting cellular
functions of melanocytes

97. • these nevi exhibit increased numbers of suprabasal
melanocytes, suggesting UV-induced alterations of
melanocyte- keratinocyte and/or melanocyte-basement
membrane interactions
• Despite the clinical, epidemiological, and
histopathological data, the life cycle of melanocytic nevi
remains to be clarified

98. JUNCTIONAL NEVUS
• Sharply demarcated, brown or black macule
• <6mm in diameter
• Lesional cells found at the junction between epithelium
and connective tissue

99. COMPOUND NEVUS
• Slightly elevated soft papule
• Lesional cells present along the junctional area and
within the underlying connective tissue

100. INTRADERMAL/INTRAMUCOSAL
NEVUS
• Nevus cells loses pigmentation
• Papillomatous and hair growth seen.
• Lesional cells found within connective tissue

101. VARIANTS OF MELANOCYTIC NEVUS
• CONGENITAL NEVUS
o melanocytic nevi clinically detectable either at birth or, at
the latest, during the first weeks of postnatal life
oCLASSIFICATION
- small (<15 cm),
- medium (15–20 cm), and
- large ( >20 cm)

103. HISTOLOGIC CRITERIA
(1) presence of nevus cells in the lower two thirds of the
reticular dermis or in the subcutis,
(2) presence of these deep nevus cells between collagen
bundles singly or in groups, and
(3) involvement of skin appendages, nerves, and vessels

104. HALO NEVUS
• Melanocytic nevus with a pale hypo-pigmented border
• Halo develops as immune cells attack the melanocytes
adjacent to the nevus

105. • Common on skin of trunk
• Presents as a central pigmented papule or macule
surrounded by a uniform 2-3mm zone of
hypopigmentation

106. SPITZ NEVUS (BENIGN JUVENILE
MELANOMA/ SPINDLE AND EPITHELOID
CELL NEVUS
• Uncommon type with many features similar to
melanoma.
• Young age of presentation and relatively small size
distinguishes from melanoma

107. • HISTOPATHOLOGY
- Lesional cells are spindle shaped or plump
- Epitheloid cells are multinucleated and lack
cohesiveness
- KAMINO BODIES – solitary or coalescent eosinophilic
globules are seen within epidermis or at the junction of
epidermis and dermis.

108. IHC – cells +ve for S-100, HMB-45, Melan –A

109. BLUE NEVUS/ DERMAL
MELANOCYTOMA/JADASSOHN-TIECHE
NEVUS
• Uncommon, benign proliferation of dermal melanocytes,
usually deep within the connective tissue.
• TYPES – 1. common blue nevus
2. Cellular blue nevus

110. • TYNDALL EFFECT
- The scattering of light as the light beam passes through
a colloid.

111. • Melanin particles located deep to the surface
• Light reflected back has to pass through the overlying
tissue
• Colours with long wavelengths are absorbed by the
tissue
• Hence, shorter wavelength blue light is reflected back

112. • Exhibits mutation of GNAQ gene
COMMON BLUE NEVUS
• May affect any cutaneous or mucosal site
• Macular or dome shaped smaller than 1cm.
• Seen in children or young adults
CELLULAR BLUE NEVUS
• 2nd to 4th decades of life
• Slow growing blue-black papule/nodule of size 2cm or
more

115. TYPES OF DEVELOPMENTAL NAEVI
1. Nevoid basal cell carcinoma
2. Epidermal nevus
3. Nevus sebaceus
4. Nevus flammeus
5. White sponge nevus

116. NEVOID BASAL CELL CARCINOMA
SYNDROME (GORLIN SYNDROME)
• Autosomal dominant
• Mutations in patched (PTCH) gene on chr 9.
• Prevalence estimated to be 1 in 19,000 to 1 in 256,000

117. GENOMICS
• PTCH1 gene is a tumor suppressor gene
• a small piece of chromosome 9 is deleted in each cell.
• Mutations in this gene prevent the production of patched-1 or
lead to the production of an abnormal version of the receptor
• An altered or missing patched-1 receptor cannot effectively
suppress cell growth and division
• cells proliferate uncontrollably to form the tumors that are
characteristic of Gorlin syndrome.

118. EPIDERMAL NEVUS
• Epidermal nevi are benign, hamartomatous growths of the
skin that are present at birth or develop in early childhood.
• Epidermal nevi originate from pluripotential germinative cells
in the basal layer of the embryonic epidermis.
• Forms of mosaicism, resulting from postzygotic mutations (or
other genetic alteration) in embryonic cells destined to
populate a particular area of the epidermis.
• mutations occurring very early in embryonic development give
rise to more extensive epidermal nevi and may potentially
affect additional organ systems

119. • Linear epidermal nevus syndrome is a congenital
neurocutaneous disorder characterized by linear
epidermal nevus with significant involvement of the
nervous, ophthalmologic, and/or skeletal systems

121. NEVUS SEBACEUS
• Sebaceous naevi are epidermal hamartomas comprised
predominantly of sebaceous glands.
• usually sporadic, common in head and neck region

122. DYSPLASTIC NEVUS

123. MELASMA/MASK OF
PREGNANCY/CHLOASMA
• Acquired, symmetrical hyperpigmentation of the sun-
exposed skin of the face and neck.
• UV light and hormonal changes are supposed to be
causative factors.
• Classically associated with pregnancy
• Bilateral brown or cutaneous macules

124. • Increased number of melanocytes in epidermis
• Numerous melanophages are also seen

125. REFERENCES
• Pathologic basis of disease – Robbins and Cotran
• Shafer’s textbook of oral pathology
• Oral and maxillofacial pathology – Neville, Damm, Chi, Allen
• Burkett’s Textbook of Oral Medicine
• Rook’s Dermatology vol – 2
• Concepts of nevogenesis – medscape
• Internet sources

126. THANK YOU

127. K . N A V I N N A I R
J U N I O R R E S I D E N T
PIGMENTED LESIONS OF ORAL
CAVITY – 3
NON-MELANIN PIGMENTATION

128. CONTENTS
• Inflammation induced pigmentation.
• HIV induced pigmentation
• Drug induced pigmentation
• Kaposi’s sarcoma
• Varix
• Angiosarcoma
• Hemosiderin pigmentation
• Exogenous pigmentation

129. POSTINFLAMMATORY PIGMENTATION
• acquired hypermelanosis occurring after cutaneous
inflammation or injury that can arise in all skin types

130. PATHOGENESIS
PIH within the epidermis
• results from the overproduction of melanin or an irregular
dispersion of pigment after cutaneous inflammation.
• there is an increase in the production and transfer of
melanin to surrounding keratinocytes.

131. • why is there an increase in melanocytic activity??
• melanocyte activity has been shown to be stimulated by
prostanoids, cytokines, chemokines, and other
inflammatory mediators and reactive oxygen species that
are released during the inflammatory process

132. • PIH in the dermis – inflammation induced damage to
basal keratinocytes,
• There is release of large amounts of melanin.
• The free pigment is then phagocytosed by macrophages
- MELANOPHAGES, in the upper dermis
• producing a blue-grey appearance to the skin at the site
of injury

133. • ETIOLOGY
1. Infections
2. Dermatophytoses
3. Hypersensitivity reactions
4. Cutaneous injury

134. • CLINICAL MANIFESTATIONS
manifests as macules or patches
location of the excess pigment within the layers of the
skin will determine its coloration
• TREATMENT
Removal of inflammatory agent
Photoprotection
Topical depigmenting creams
Medical therapy

135. HIV INDUCED PIGMENTATION
Immune system is dysregulated with release of inflammatory
mediators like IL 1, IL 6
A febrile response which triggers release of alpha MSH
Alpha MSH is a potent stimulator of melanocytes
IL 1 up regulates MSH receptor in melanocytes
Contributes to pigmentation
In patients infected with MAC, there is adrenal hypofunction.
Release of ACTH and MSH
Use of drugs also causes hyperpigmentation

136. DRUG INDUCED PIGMENTATION
hormones, oral contraceptives, chemotherapeutic
agents,antimicrobial agents
Palate and gingiva are most common sites
drug or drug metabolite deposition in dermis and epidermis
Enhanced melanin deposition with or without increase in
melanocytes
Drug induced post inflammatory changes to the mucosa

137. HEMOGLOBIN PIGMENTATION
1. VARIX
2. ANGIOSARCOMA
3. KAPOSI’S SARCOMA

138. HEMOGLOBIN PHYSIOLOGY
• iron-containing oxygen-transport metalloprotein in the
red blood cells of all vertebrates.

139. SYNTHESIS
• A haemoglobin molecule is composed of four
polypeptide globin chains.
• Each contains a haem moiety which has an organic part
(a protoporphyrin ring made up of four pyrrole rings) and
a central iron ion in the ferrous state.

140. • HAEM - Haem synthesis occurs both in cytosol and in
mitochondria of erythrocytes.
• Protoporphyrin is synthesized from the condensation of
glycine and succinyl coenzyme A.
• The protoporphyrin then binds to a Fe ion to form haem

141. • IRON - The Fe2+ ion forms six bonds within the haem
moiety.
• Five of these bind the Fe firmly: four with nitrogen atoms
in the centre of the protoporphyrin ring, and one to a
‘proximal’ histidine residue

142. KAPOSI’S SARCOMA/
ANGIORETICULOENDOTHELIOMA
• It is a low grade vascular tumour that may involve the
skin, mucosa and viscera.
EPIDEMIOLOGY
• Now the most common prevalent malignancy among
patients with AIDS
• There is evidence for sexual, horizontal, and parenteral
transmission in the medical literature

143. VIROLOGY
• In 1994, detection of a viral DNA fragment in Kaposi
sarcoma tissue was reported and this virus was called
Kaposi sarcoma-associated herpesvirus (KSHV) or
human herpesvirus 8 (HHV-8).

144. PATHOPHYSIOLOGY
• HHV 8 targets human B cells, monocytes, endothelial
cells, keratinocytes.
• HHV-8 is endocytosed by macropinocytosis and may
remain latent
• Only LANA is expressed which suppresses genes for viral
production and assembly.
• It has the ability to bind and inhibit tumour suppressor
genes, p53 and Rb
• Thus, the cells can undergo uninhibited proliferation

145. PATHOGENESIS OF KS
• Circulating blood mononuclear and endothelial
‘‘progenitor cells’’ are source of early lesions.
• Infection with HHV8 reprograms the host’s blood
endothelial cells so that they resemble lymphatic
endothelium
• Up regulation of several lymphatic associated genes
1. lymphatic vessel endothelial receptor 1 (LYVE1)
2. podoplanin, and
3. vascular endothelial growth factor receptor 3
(VEGFR3)

146. • KS progression relies on some degree of host immune
dysfunction and the local inflammatory milieu
• Kaposi sarcoma growth involves the up regulation of
many key HHV8 gene products like LANA

147. CLINICAL FEATURES

148. HISTOPATHOLOGY
1. PATCH STAGE
- earliest phase in the evolution of cutaneous KS
- subtle vasoformative process composed of newly formed
slitlike or somewhat jagged vascular spaces.
- mild background inflammatory cell infiltrate
- Often with presence of hemosiderin laden macrophages

149. newly formed vessels protruding into a larger vascular space characteristic
of the promontory sign

150. 2. PLAQUE STAGE –
- proliferation of both spindle cells and vessels.
- Well-developed KS tumors consist of several fascicles of
these spindle-shaped tumor cells often admixed with a
variable chronic inflammatory infiltrate composed of
lymphocytes, plasma cells, and dendritic cells.
- Mitotic figures are sparse
- "autolumination", whereby an erythrocyte is contained
within a clear paranuclear vacuole in the cytoplasm of a
spindled endothelial cell

152. 3. NODULAR STAGE –
- circumscribed, variable cellular proliferation of neoplastic
spindled cells arranged in fascicles
- Erythrocytes are contained within slitlike channels
between the individual spindled cells.
- Hyaline globules and autolumination are seen more
readily

154. • IHC
- stain positively with the endothelial markers factor VIII–
related antigen, CD31 (PECAM-1), and CD34.
- several lymphatic specific markers such as D2-40, LYVE-1,
VEGFR-3 and Prox-1.
- The identification and localization of HHV8 within KS lesional
cells by using LNA-1 is the most diagnostically helpful
immunostaining technique available to differentiate KS from
its mimics

156. ANGIOSARCOMA
• Malignancy of the inner lining of blood vessels and it can
occur in any area of the body.
• trauma, longstanding lymphedema, and irradiation are
predisposing factors.
• predominantly affects elderly patients
• Men are affected twice as frequently as women
• localized mostly to the upper half
of the face and the scalp

157. • HISOPATHOLOGY
- Endothelium lined blood vessels that form anastomosing
network.
- Endothelial cells appear hyperchromatic
• TREATMENT
- Radical surgical excision

158. VARIX
• Acquired benign lesions of a vein abnormally dilated and
tortuous.
• Affects mainly adults and no gender predilection
• Ventral aspect of tongue > lower lip
• Irregular blue/purple lesions
• Diagnosed clinically only
• No treatment usually required.

159. HEMOSIDERIN PIGMENTATION
• Hemosiderin hyperpigmentation is pigmentation due to
deposits of hemosiderin, and occurs in purpura,
hemochromotosis, hemorrhagic diseases, and stasis
dermatitis
• formation and location
of hemosiderin is associated with
the destruction of blood

160. HEMOSIDEROSISHEMOCHROMATOSIS/
BRONZE DIABETES
• chronic, progressive disease that is characterized by
excessive iron deposition in the liver and other organs
and tissue leading to organ toxicity.
• Classification
1. Hereditary hemochromatosis
2. Acquired hemochromatosis

161. HEREDITARY HEMOCHROMATOSIS
CLASSIFICATION
- HFE related
- Non HFE related
GENOMICS
- Gene responsible is HFE.
- Autosomal recessive inheritance pattern

162. • MUTATIONS IN HFE
- A single nucleotide change, resulting in the substitution
of tyrosine for cysteine at amino acid 282 of the
unprocessed protein (C282Y)
- substitution of aspartate for histidine at amino acid 63
(H63D).

163. • LINK BETWEEN HFE AND IRON METABOLISM
- HFE protein forms a complex with transferrin receptor 1
(TfR1).
- HFE is capable of changing cellular iron status of cells
which do not express TfR1 at all, suggesting that HFE
can influence cellular transport of non-transferrin bound
iron

164. • PETECHIAE - Petechiae are submucous or
subcutaneous minute pinpoint hemorrhages.
• Capillary hemorrhages will appear red initially and turn
brown in a few days once the extravasated red cells
have lysed and have been degraded to hemosiderin

165. • ECCHYMOSIS –
• Whenever trauma occurs, the erythrocytes comes out in
to submucosa and appear as a bright red macules and
• then lesion become brown in color in few days, as
hemoglobin is degraded into hemosiderin

166. EXOGENOUS PIGMENTATION

167. AMALGAM TATTOO
• Is an iatrogenic lesion caused by traumatic implantation of
dental amalgam into soft tissue.
• clinically present as isolated, blue, grey, or black macules
• Gingiva > buccal mucosa
• lesions are usually non-painful
• due to deposition of a mixture of silver, tin, mercury, copper,
and zinc, which are components of an amalgam filling, into
the oral soft tissues

168. • These tattoos do not represent a health hazard since the mercury present in
amalgam is not in a free state
• discrete, fine, dark granules and irregular, solid fragments. They can be found
along collagen bundles and vessels and also are found within macrophages,
mulinucleated giant cells, fibroblasts, and endothelial cells.

169. GRAPHITE TATTOO
• Pencil points are occasionally broken off in gingival
tissue and if not completely removed, may cause
permanent discoloration as graphite tattoo.
• The color of the lesion can be gray or black.
• Graphite particles resemble those of amalgam

170. PIGMENTATION RELATED TO HEAVY
METAL INGESTION
1. Bismuthism
2. Plumbism
3. Mercurialism
4. Argyriosis
5. Arsenism
6. Auric stomatitis

171. BISMUTH DISCOLOURATION
- caused by medicinal use of bismuth containing
preparation.
- Pigment is precipitated granules of bismuth sulphide
formed by reaction with hydrogen sulphide
- The hydrogen sulphide is formed through bacterial
degradation of organic material/food debris
• Blue black” bismuth line appears to be well demarcated
on gingival papillae.
• Establishing and maintaining
oral hygiene and stoppage
of use of bismuth will
decrease its effect.

172. PLUMBISM
- caused by lead in the paints, glazes, cooking vessels,
batteries, ointment and containers
- There is a metallic taste which is accompanied by
excessive salivation and dysphagia.
- Gray/bluish black line of sulfide pigmentation occurs in
the gingiva

173. • ACRODYNIA/PINK DISEASE
- It is an uncommon disease caused due to a mercury
toxicity reaction, either actual mercury poisoning or an
idiosyncrasy to the metal.
- Skin becomes red/pink with cold clammy feeling
- Maculopapular rash, sweating, photophobia, weakness,
salivation, bruxism

174. ARGYROSIS
- due to chronic exposure to silver compound.
- skin is slate gray, violet or cyanotic
- Pigmentation is distributed diffusely throughout the
gingival and mucosal tissue

175. • ARSENISM
- due to arsenic poisoning from industrial exposure or
intentional use or due to therapeutic consumption
- Dry mouth, gingivitis, ulceration

176. AURIC STOMATITIS
- Vesiculations and ulcerations of the oral mucosa
- faint blue or purple discoloration

177. SUMMARY
• What is pigmentation?
• Classification of pigmented lesions?
• Melanin physiology?
• Melanocytic disorders?
• Hemoglobin pigmentation disorders?
• Exogenous pigmentation?

178. CONCLUSION
• The variation of normal colour of one’s mucosa should
be promptly noted.
• Many disease mechanisms may be related to change in
the appearance of mucosal colour.
• The definitive pathology requires biopsy and
histopathologic examination
• An understanding of various disorders and substances
that can contribute to oral and perioral pigmentation is
essential for appropriate evaluation, diagnosis, and
management of patient

179. THANK YOU