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skin tumors (pathological slides) skin pathologies
- 1. Neoplasms of Skin By:Dr. Unaiza
- 2. Classification • Tumours ofskin are broadly classified as Benign, Premalignant and Malignant • They may also be classified according to their origin as: • Epidermal • Appendageal – Pilar (hair), sebaceous and sweat gland • Melanocytic • Mesodermal origin (vascular and connective tissue)
- 3. Tumours Arising fromEpidermis • Benign • Seborrheic keratosis • Epidermal nevi • Keratoacanthoma • Premalignant • Actinic keratosis • Leukoplakia • Bowen's disease • Paget's disease • Malignant • Squamous cell carcinoma
- 4. Classification Keratinocytic tumors • Basalcell carcinoma • Squamous cell carcinoma • Melanocytic tumors • Malignant melanoma
- 5. Benign and Premalignant EpithelialLesions • Benign epithelial neoplasms are common and probably arise from stem cells residing in the epidermis and hair follicles. • These tumors grow to a limited size and generally do not undergo malignant transformation.
- 6. Seborrheic keratosis • Themost common benign skin neoplasm. • No malignant potential. • Origin is unknown. • more frequent in middle age and older persons • Tend to occur on trunk most often, but can appear on head and extremities. • Lesions contained entirely in epidermis
- 7. Appearance • Size canrange from 0.2 to 3.0 cm in diameter. • Can have smooth surface or be rough and cracked. • Characteristic "stuck-on" appearance. • Color can be tan, brown, or black. • Can resemble melanoma (SK has uniform surface • appearance). • Key to visual diagnosis is identification of horn cysts • Black or pearly-white cysts either embedded in or on the surface of the lesion. • These are dilated follicular Ostia filled with keratin.
- 8. Seborrheic keratosis Seborrheic Keratosis:May be flat with some scale (left) or raised (right) with deep cracks.
- 9. Seborrheic keratosis • SeborrheicKeratosis: have characteristic horn cysts. They can be white and deeper seated (left) or black and superficial (right).
- 10. Seborrheic Keratosis: Melanoma Look-Alikes •Seborrheic Keratosis: Has dark pigmentation, irregular borders, and some variation of color, but horn cysts help to make diagnosis clinically.
- 11. Actinic Keratosis Definition • Actinic(or solar) keratosis is a premalignant epithelial lesion directly related to long-term sun exposure • classically found on sun-exposed areas of the skin( face,arm,dorsum of hand) • A small percentage of these lesions will transform into squamous cell carcinoma.
- 12. • Also calledsolar keratosis. • Lesions increase with age. • Can spontaneously regress if sun-exposure is removed. • Lesions have increased vascularity (erythematous). • Develops adherent white or yellowish scale. • Can bleed if picked. • Many lesions are more readily identified by rough texture than appearance. Actinic Keratosis
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- 14. Actinic Keratosis • Keratosis:classic appearance with scale and crust on an erythematous base (left). Many AKs on the face, the surrounding skin has irregular pigmentation and some dilated vessels (right).
- 15. Actinic Keratosis • ActinicKeratosis: thicker lesions can develop into squamous cell carcinoma (left). AK's can often clinically appear like SCC (right).
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- 17. Squamous Cell Carcinoma •Squamous cell carcinoma is a common tumor arising on sun exposed sites in older people. • higher incidence in men than in women. • these lesions have significant chance of metastasis. • UV radiation is involved in the pathogenesis of SCC. • Found in sun-exposed areas (scalp, back of hands, pinna). • Actinic keratosis is most common precursor lesion.
- 18. Risk Factors • Inaddition to sunlight, predisposing factors include : • industrial carcinogens (tars and oils) • chronic ulcers • old burn scars • ingestion of arsenicals • ionizing radiation.
- 20. Features Of SquamousCell Carcinoma • Clinically, Squamous cell carcinoma presents as a shallow ulcer with raised, everted, firm border • Wide surgical excision in sun exposed cases is usually curative • Radical lymph node dissection and other forms of adjuvant therapy may be necessary in management of other squamous carcinomas with a higher metastatic potential
- 21. Squamous Cell Carcinoma •Less than 5% have metastasized to regional nodes at diagnosis. • The likelihood of metastasis is related to the thickness of the lesion and degree of invasion into the subcutis.
- 22. Histology • Histlologically, thetumour is composed of large polygonal cells with abundant pink cytoplasm (ie, they resemble cells of prickle layer) • Atypia, pleomorphism and mitotic activity vary from minimal to marked • Keratin - containing epithelial pearls are porominant in well differentiated tumours • Invasion is usually present.
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- 24. Squamous Cell Carcinoma •Squamous Cell Carcinoma: Asymmetrical lesion; Occurs on sun - damages skin; Grows slowly; Metastasizes late
- 25. Squamous Cell Carcinoma •A nodular and hyperkeratotic lesion occurring on the ear, unfortunately with early metastasis to a prominent post auricular lymph node (arrow)
- 26. Squamous Cell Carcinoma •In situ carcinoma : • Sharply defined, red scaling plaques • Cells with atypical nuclei in all levels of epidermis • Advanced, invasive : • Nodular • Ulceration • Vvariable keratin production • Variable degrees of differentiation
- 27. Squamous Cell Carcinoma •Well differentiated squamous cell carcinoma skin. The tumour cells are strikingly similar to squamous epithelial cells. • with intercellular bridges and nests of keratin pearls
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- 29. Basal Cell Carcinoma •Cell Carcinoma Basal cell carcinoma is a common skin neoplasm • Occurs in sun exposed areas of light skinned individuals • Usually over the age of 40 years Face is the most common site involved • Clinically, early basal cell carcinoma arises from the basal layer of the epidermis and invades the dermis as nests and cords of cells. • Basal cell carcinoma is locally aggressive • It may invade deeply to involve bone and muscle but almost never metastasizes
- 30. Basal Cell Carcinoma •Advanced lesions may ulcerate and extensive local invasion of bone or facial sinuses may occur after many years of neglect or unusually of aggressive tumours, justifying the past designation "Rodent Ulcer" • Wide surgical excision is curative. • associated with mutations that activate the Hedgehog Pathway Signalling.
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- 32. Morphology • Pearly papulescontaining prominent dilated sub epidermal blood vessels • Some tumours contains • melanin; May resemble melanoma • Neglected and unusually aggressive tumours: • May ulcerate • Show extensive local invasion of bone and facial sinuses
- 33. Histologically • Tumor cellsresemble cells of normal basal cell layer of epidermis • Arise from epidermis or follicular epithelium • Do not occur on mucosal surfaces • Two types: • Multifocal growths • Nodular lesions
- 34. Multifocal growths • Originatingfrom epidermis • Sometimes extending over several square cms of skin surface
- 35. Nodular lesion • Growingdownward deeply into the dermis • Cords and islands of variably basophilic cells • Hyper chromatic nuclei Embedded in mucinouss matrix
- 36. • Multiple nodulesof basaloid cells infiltrating a fibrotic stroma. • The cells have a scant cytoplasm, small hyper chromatic nuclei, and a peripheral palisading pattern with clefting the stroma.
- 37. • Nests areoften separated from the adjacent stroma by thin clefts • Composed of nests of basaloid cells within the dermis
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- 39. Melanocytic Neoplasms • NevocellularNevus (Melanocytic • Nevus) • Congenital Melanocytic Nevus • Blue Nevus • Malignant Melanoma in Situ • (Non invasive malignant melanoma) Invasive Malignant Melanoma
- 40. • The TermNEVUS: Latin naevus means Mole • The Term NEVUS is used in general sense for many cutaneous lesions present at birth
- 41. Nevocellular Nevus (Melanocytic nevus) •Melanocytic Nevi are usually not present at birth but appear in childhood and stop growing soon after puberty. • Extremely common. • They are benign and present clinically as flat, papular, papillomatous or pedunculated pigmented (black or brown)lesions • If a nevus changes its form in any way, malignancyshould be suspected.
- 42. Nevocellular Nevus 1. Histologically,moles are composed of nests of nevus (Melanocytic) cells, which may be found in the: 2.Dermis: Inradermal Nevus 3.At the junction between epidermis and dermis: Junctional Nevus OR 4. in both locations: Compound Nevus
- 43. Nevocellular Nevus -Junctional Type • A: In clinical appearance, lesions are small, relatively flat,Symetric and uniform • B: On histological examination, Junction nevi are charterized by rounded nests of nevus cells originating at the tips of rete ridges along the dermoepidermoid junction
- 44. Nevocellular Nevus Junctional Type •A: In clinical appearance, lesions are small, relatively flat, symmetric and uniform • B: On histological examination, Junctional nevi are charterized by rounded nests of nevus cells originating at the tips of rete ridges along the dermoepidermoid junction
- 45. Dysplastic Nevi • Specialtype of nevus that tend to be: • (a) familial • (b) frequently multiple • (C) commonly more than 5 mm in diameter • In affected families, the disease has an autosomal dominant inheritance pattern • show disordered architecture features on histological examination and may show cytologic atypia • Dyspalstic nevi are premalignant • Families with dysplastic nevi have an increased risk (5 -10%) of developing malignant melanoma
- 46. Dysplastic Nevi • usuallylarger than most acquired nevi (more than 5mm across) • May occur as hundreds of lesions on the body surface • Flat macules to slightly raised plaques with a "pebbly surface Usually show variable pigmentation (variegation) and irregular borders • Unlike ordinary nevi,dyspalstic nevi have a tendency to occur on body surfaces not exposed to the sun, as well as on sun exposed body surfaces
- 47. Dysplastic Nevi • Numerousirregular nevi on the back of this individual suggest the dysplastic nevus syndrome; the clinical features are intermediate to those of benign nevi and melanoma. The lesions are usually greater than 5 mm in diameter with irregular borders and variable pigmentation
- 48. Dysplastic Nevi • -Acentral dermal component, which correlates the more pigmented and raised central zone - An asymmetric "shoulder" of exclusively junctional melanocytes, which correlates the less pigmented flat peripheral rim • - An important feature is presence of cytologic atypia (irregular,Dark-stained nuclei)
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- 51. Malignant Melanoma • MalignantMelanom a relatively common neoplasm. • Although the great preponderance of melanomas arise in skin, other sites of origin are oral and anogenital mucosal surfaces, esophagus, meninges and notably eye. • Once was considered almost uniformly deadly Today as a result of increased public awarness of the earliest signs of melanomas, most are cured surgically. The incidence of these lesions is on the rise, necessitating vigorous surveillance of their development
- 52. Malignant Melanoma • Incidenceis highest in sun exposed skin and in geographic locales such as New Zealand and Australia where sun exposure is high and protective mantle of melanin is sparse • Predisposing factors other than sunlight are: • - Presence of preexisitng nevi • - Hereditary predisposition
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- 54. Predisposing Factors • Aswith epithelial malignant neoplasms of the skin,sunlight appears to play an important role in the development of skin malignant melanomas • Lightly pigmented individuals are at higher risk for the development of melanomas than are darkly pigmented individuals. Sunlight, however does not seem to be the predisposing • factor Presence of a prexisitng nevus (Dysplastic nevus), hereditary factors or even exposure to certain carcinogens may play a role.
- 55. Molecular Genetics ofmalignant melanoma show association • Melanomas which run in families shows association with • - Dyspasitic nevi • - Genetic events • Genes involved in Malignant Melanoma • Genes which promote malignant proliferation • - CMM1 Gene • -DCK4 Gene • Tumour suppression Gene: Its mutation leads to malignant • growth
- 56. Molecular Genetics ofmalignant melanoma As with other tumours, malignant transformation is a multistep process with: • a) Activating mutations in proto-oncogenes • b) Loss of tumour suppressor genes
- 57. Clinical features ofMalignant Melanoma • Malignant melanoma of skin is usually asymptomatic • Itching may be the early manifestation • The most important clinical sign of the disease is the change in colour in a pigmented lesion. Unlike benign (nondyspasltic) nevi, melanomas exhibit striking variations in pigmentation, appearing in shades of black, brown, red, dark blue and gray. • On occasion zones of white or flesh coloured Hypopigmentation are also present
- 58. Clinical warning signsof Malignant Melanoma • (1) Enlargement of pre-existing mole • (2) Itching or pain in a pre-existing mole . • (3) Development of a new pigmented lesion during adult life • (4) Irregularity of the borders of a pigmented lesion • (5) Variegation of colour within a pigmented lesion Borders of Benign Nevi Borders of Malignant Melanoma Smooth, round and uniform Irregular, coarse and often notched
- 59. Malignant Melanoma: Recognizing SuspiciousNevi • ABCD's of moles: • Asymmetry • Borders : irregular edges • Color :Uneven pigmentation ,Various shades brown,black, red • Diameter :Greater than 6mm
- 60. Growth pattern ofMalignant Melanoma • A: Radial Growth: Indicates the tendency of melanoma to grow horizontally within the epidermal and superficial layers, often for a prolonged time • B: Vertical Growth: After passage of time the pattern of growth assumes a vertical component and the melanoma now grows downward into the deeper dermal layers as an expensile mass.
- 61. Growth pattern ofMalignant Melanoma
- 62. Malignant Melanoma: Radial Growth •showing irregular nested and single cell spread of melanoma cells in the epidermis.
- 63. Malignant melanoma: Vertical Growth •Showing nodular aggregates of malignant cells extending deeply within the dermis
- 64. Morphological findings in MalignantMelanoma • Individual cells are usually considerably larger that nevus cells. They contain large nuclei with irregular contours, having chromatin characteristically clumped at the periphery of the nuclear membrane and prominent red (eosinophilic) nucleoli;often described as "Cherry Red" nucleoli. • These cells proliferate as poorly formed nests or as individual cells at all levels of the epidermis in the radial phase of growth and in the dermis as expansile, balloon like nodules in the vertical phase of the growth. • Thus it is important to observe and record vertical growth phase parameters in a pathology report.
- 65. Malignant Melanoma: Microscopic Features •Melanoma cells have hyper chromatic nuclei of iregular size and shape with prominent nucleoli. Mitosis, including atypical forms such as seen in the center of this field are often encountered
- 66. Main Features ofCommon Malignant Skin Tumours
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