Sinonasal tract pathology(histopathology)

SINO-NASAL TRACT
PATHOLOGY
Guide: Dr. Nandini J. Desai ma`am
Co-Guide: Dr. Dimple Sangani ma`am
Presented by: Dr. Anuj kumar

The two main types of epithelia linings are :
1) Stratified squamous
2) Respiratory-type(pseudostratified ciliated columnar).
-Roof of nasal cavity contains olfactory mucosa. In infantsitextends to the mid
portion of nasal septum and upto superior turbinate. In adults it is replaced by
respiratory epithelium.
 Olfactory mucosa has 3 types ofcells-
1. Olfactory nervecells(Bipolar cells)
2. Sustentacular cells (Supporting cells)
3. Basal cells.

Contents…
1) Inflammatory lesions
2) Benign lesions
3) Malignant lesions

Inflammatory lesions
1) Rhinosinusitis
2) Sinonasal Polyp
3) Nasal Glial Hetrotropia
4) Allergic Fungal sinusitis and Invasive fungal sinusitis
5) Rhinoscleroma
6) Rhinosporiodosis
7) Wegener Granulomatosis
8) Respiratory Epithelial Adenomatoid Hamartoma
9) Myospherulosis

RHINOSINUSITIS
Respiratory mucosa with a mixed chronic
inflammatory infiltrate composed
predominantly of lymphocytes and plasma
cells.
Allergic sinusitis: Respiratory mucosa with a
prominent eosinophilic infiltrate and a
thickened basement membrane, suggestive
Of an allergic etiology.

SINO-NASAL POLYPS
Two different sino-nasal tract polyps, both showing a glistening, wrinkled surface, with a
translucent appearance.

Inflammatory (Including “Allergic”) Polyp:
• A morphologically similar type polyp can be seen arising from one of the
paranasal sinuses; this is referred to as choanal polyp and is subdivided according
to its specific location into antrochoanal (the most common), sphenochoanal, and
ethmoidochoanal.
• Eosinophils are not restricted to the polyps having a presumed allergic
pathogenesis, although they are more numerous in them.
Prominent thickening of the basal membrane is a common accompanying finding.

Etiologies : include allergy, infection, diabetes,
aspirin sensitivity, asthma, cystic fibrosis, nickel exposure
Microscopic Findings:
• Mucosa may be metaplastic but is usually intact
• Edematous lamina propria with lymphoplasmacytic infiltrate, with occasional
eosinophils (depends on etiology)
• Mucoserous glands may have goblet cell metaplasia
• May have “stromal atypia” with myofibroblastic cells
• Antrochoanal polyps are fibrotic with reduced or absent glands
• Pseudoangiomatous change, infarction, organization, and secondary infections
may result

Allergic nasal polyp showing a large
number of eosinophils and associated
chronic inflammation
Bizarre stromal cells in a nasal polyp, set
against an edematous and inflammatory
background.

NASAL
GLIAL HETEROTOPIA
Definition:Congenital malformation
of displaced, mature glial tissue
without an intracranial connection
Incidence :Uncommon
Location: Extranasal (60%),
intranasal (30%), mixed (10%)
Gender and Age Distribution:
-Equal gender distribution
-Most frequent during infancy, rare
in adults
-Nasal glial heterotopia resembles
gliosis
-Glial tissue blended with fibrosis
below intact surface
-Astrocytic cells may show
gemistocytic change
-Encephaloceles appear identical to
normal brain tissue, but
degeneration may result in loss of
neurons
Gross:
Smooth, homogeneous, glistening cut surface
Can be firm if there is extensive fibrosis
Polyp if within the nasal cavity

Gemistocytic astrocytes are noted within a
fibrillar neural matrix.
Ganglion-like cells set in a background with
abundant neural matrix.

Allergic fungal sinusitis:
Definition:
An allergic response within the sinonasal
tract to fungal allergens, amplified and
perpetuated by eosinophils
Gross Findings:
• Putty-like, peanut butter–like, muddy
secretions
• Alternating “tide-lines,” waves, or ripples
of mucin with degenerated debris,
eosinophils, Polymorphonuclear cells
• Charcot-Leyden crystals may be present
(from degenerated eosinophils)
• Fungal hyphae may be sparse, highlighted
by fungal stains
• Fungi cultured include Aspergillus,
dematiaceous fungi (bipolaris, curvularia,
alternaria, exserohilum)
Allergic fungal sinusitis Alternating “tide- lines” or
ripples of eosinophils and neutrophils Characterize
allergic fungal sinusitis.

Rhinosporidiosis
• It is characterized by hyperplastic
polypoid lesions of the nasal cavity
and rarely other mucous
membranes.
• The diagnosis is readily made by
the identification of numerous
globular cysts measuring up to 200
nm in diameter.
• Each of these cysts represents a
thick-walled sporangium containing
numerous spores.
• Molecular studies indicate that
Rhinosporidium seeberi clusters
with a novel group of
fish parasites.
Large globular cysts are present surrounded by
a heavy inflammatory reaction.

Rhinoscleroma (scleroma)
Definition:
• A chronic, progressive, upper
aerodigestive tract infection caused
by Klebsiella rhinoscleromatis
• F>M, 2nd -3rd decade peak
Gross:
Friable inflammatory polyps or dense
fibrosis.

Groups, clusters and sheets of large,
vacuolated macrophages (Mikülicz cells),
which contain the infective organisms
Dense lymphoplasmacytic inflammation with
Russell bodies (in plasma cell usually)

Myospherulosis
Myospherulosis:
It is an iatrogenically induced
granulomatous condition of the nose and
paranasal sinuses. It is a form of
lipogranuloma that develops after
hemostatic packing with petrolatum
based ointments and gauze,
• Microscopically, its distinctive feature is
the presence of large tissue spaces
containing sac like structures with brown
“spherules” resembling fungi. It turns out
that these mysterious formations are
simply erythrocytes that have been
altered and clumped by the action of the
petrolatum.
Myospherulosis of paranasal sinus following an
operation in the region for fibromatosis. A “bag”
containing round structures is seen floating in a
tissue cavity surrounded by fibrous tissue.

WHO CLASSIFICATION (2017)
of tumors of nasal cavity, paranasal sinuses and skull base
• Sino nasal papilloma
• Carcinomas
• Teratocarcinosarcomas
• Respiratory epithelial lesion
• Salivary gland tumors
• Malignant soft tissue tumors
• Borderline / low grade malignant soft tissue tumors
• Benign soft tissue tumors
• Hematolymphoid tumors
• Neuroendocrinal/ Melanocytic tumors
• Other tumors

Carcinomas
• Keratinizing squamous cell carcinoma
• Non-keratinizing squamous cell carcinoma
• Spindle cell squamous cell carcinoma
• Lymphoepithelial carcinoma
• Sinonasal undifferentiated carcinoma
• NUT carcinoma
• Neuroendocrine carcinomas
• - Small cell neuroendocrine carcinoma
• -Large cell neuroendocrine carcinoma
• Adenocarcinomas
• -lntestinal-type adenocarcinoma
• -Non-intestinal-type adenocarcinoma

Malignant soft tissue tumours
• Fibrosarcoma
• Undifferentiated pleomorphic sarcoma
• Leiomyosarcoma
• Rhabdomyosarcoma, NOS
• Embryonal rhabdomyosarcoma
• Alveolar rhabdomyosarcoma
• Pleomorphic rhabdomyosarcoma, adult type
• Spindle cell rhabdomyosarcoma
• Angiosarcoma
• Malignant peripheral nerve sheath tumour
• Biphenotypic sinonasal sarcoma
• Synovial sarcoma

Benign soft tissue tumours:
• Leiomyoma
• Haemangioma
• Schwannoma
• Neurofibroma
Haematolymphoid tumours :
• Extranodal NK/T-cell lymphoma
• Extraosseous plasmacytoma

Neuroectodermal / melanocytic
tumours
• Ewing sarcoma/ primitive neuroectodermal tumour
• Olfactory neuroblastoma
• Mucosal melanoma

Sinonasal Papillomas
• Sinonasal papilloma- Inverted type
• Sinonasal papilloma- Oncocytic type
• Sinonasal papilloma- Exophytic type

Sinonasal papilloma- Inverted type
Gross:
Surgical specimen of an inverted Schneiderian
papilloma with polypoid appearance. The
cerebriform surface shows numerous clefts due to
exuberant endophytic epithelial proliferation
Sinonasal Papilloma With Inverted Pattern of
Growth

Sinonasal papilloma- Oncocytic type
Oncocytic cell Schneiderian papilloma with stratified columnar respiratory epithelium with
oncocytic cells and small neutrophilic abscesses. These structures are within the epithelium

Sinonasal papilloma- Exophytic type

Exophytic
Schneiderian papilloma
with koilocytic atypia,
hyperkeratosis, and
parakeratosis.

A large number of inflammatory cells and small micro-
abscesses are noted in this inverted Schneiderian
papilloma

LOBULAR CAPILLARY HEMANGIOMA
(PYOGENIC GRANULOMA)
Definition:
• Benign vascular tumor with lobular
architecture composed of
• variable size vessels with proliferating
endothelial cells
Incidence and Location:
Common Anterior nasal septum (60%), nasal
vestibule (20%), turbinates (20%)
• Boys ,15 years
• Females in reproductive years
• Older adults no gender differences
Prognosis and Treatment:
• Excellent prognosis with no significant
recurrences
• Complete endoscopic resection with
bleeding control

A lobular arrangement around large patulous
vessels is seen in this lobular capillary
hemangioma (LCH) at low power.
LCH with lobular architecture
demonstrating cellular lobules with
larger dilated blood vessels

Gross Findings:
• Sessile, polypoid, or nodular red to purplish mass
• Ulceration is common
• Lobular architecture with mixture of thin and thick
blood vessels
• Central vessel surrounded by cellular lobule of
closely packed capillaries
• Plump endothelial cells with bland nuclear features
and scanty to moderate eosinophilic cytoplasm
• Frequent mitotic figures
• Edematous to fibrotic stroma with mixed
inflammatory infiltrate
• Ulcerated surface with fibrinous exudate simulating
granulation tissue
Immunohistochemical Features:
• Endothelial cells positive for CD31, CD34, factor
VIII–RAg
• Actins positive in pericytes and smooth muscle cells
Pathologic Differential Diagnosis:
• Nasopharyngeal angiofibroma,
glomangiopericytoma (sinonasaltype
hemangiopericytoma), angiosarcoma

GLOMANGIOPERICYTOMA (SINONASAL TYPE
HEMANGIOPERICYTOMA)
.
Other names,including Hemangiopericytoma-like tumor, Sinonasal-
typehemangiopericytoma, and Glomangiopericytoma.
Definition:
• A sinonasal tumor demonstrating
perivascular myoid phenotype
Age/sex:
• Slight female predominance (1.2:1)
• Mean, 7th decade (range, in utero to 90
years)

Eosinophils and mast cells are common in
glomangiopericytoma, along with
extravasated erythrocytes.
A characteristic histomorphologic feature is
the presence of prominent perivascular
hyalinization.

• An 18-year-old male with a
history of recurrent nasal
epistaxis undergoes the resection
of a mass located in the
posterolateral wall of the roof of
the nasal fossa. Histologically, the
lesion consists of a bundle of
vascular structures within a
stroma rich in stellate cells and
mast cells, as shown in this
picture. Which hormones is
thought to play a role in the
pathogenesis?

NASOPHARYNGEAL ANGIOFIBROMA
Definition:
• A benign, highly cellular, and richly
vascularized mesenchymal neoplasm that
arises in the nasopharynx in males.
• Uncommon, incidence of 1/150,000 males
• 1% of nasopharyngeal tumors Posterior
nasal wall, roof of nose and nasopharynx.
Gross Findings:
• Round or nodular, nonencapsulated
masses with sessile or pedunculated base
• Intact mucosa with focal areas of
ulceration and superficial hemorrhage.
• Cut surface showing dilated vascular
channels which give the tumors a spongy
appearance or solid, fibrotic tumors
• Mean size, 4 cm

• Combination of abnormal vascular network, a
connective tissue stroma, and stromal cells.
• Vascular network with variable sized vessels,
from thin-walled, slit-like to large irregular
vessels.
• Muscle layer is absent, focal, pad-like, or
circumferential.
• Spindle, stellate, angular stromal cells in
collagenized background
• Inflammatory cells usually absent
• Increased fibrosis with treatment; embolic
material may be seen.
• Vessel walls positive with vimentin
• Endothelial cells positive for CD34, CD31,
androgen, estrogen and progesterone receptors,
factor VIII–RAg
• Stromal cells positive for vimentin, b-catenin,
androgen receptors.
The intact respiratory epithelium (top) overlies a
richly vascular neoplasm with variably sized vessels
surrounded by a cellular fibroblastic stroma with
collagen.

Note the remarkable variability in the nature of the
vessels: muscle-walled vessels, pad-like muscle, and
no muscle are all seen in the vessels of this field.
Thin-walled and thick-walled vessels surrounded by
dense, “keloid-like” collagen. Stellate fibroblasts are
noted, giving a slightly “atypical” appearance.

Embolic material surrounded by multinucleated
giant cells in this nasopharyngeal angiofibroma.
The smooth muscle can be highlighted with a
smooth muscle actin immunohistochemistry, which
shows the variability of muscle around the vessels.

ECTOPIC PITUITARY ADENOMA
Definition:
• A benign pituitary neoplasm occurring
separately from, and without involvement
of the sella turcica (a normal anterior
pituitary gland).
Gender, Race, and Age Distribution:
• Females >males (1.3:1)
• Mean age, 54 years (range, 2 to 84 years)
Clinical feature: Symptoms due to nasal mass
and Visual field defects (diplopia).

• Submucosal location of unencapsulated tumor
• Tumors arranged in solid, organoid, and
trabecular patterns separated by delicate
fibrovascular septa
• Monotonous population of round or polygonal
epithelial cells with eosinophilic cytoplasm.
• Round or oval nuclei with “salt-and-pepper”
chromatin and inconspicuous or small nucleoli.
• Nuclear pleomorphism and mitoses are rare
• Necrosis can be seen in about one-third of cases
• Lymphovascular and perineural invasion are not
identified.
• Strong keratin, CD56, chromogranin,
synaptophysin, NSE reactivity.
• May stain for the hormone peptides, including
ACTH, prolactin, TSH, GH, FSH, and LH or
pituitary transcription factors.

A, Keratin.
B, Chromogranin.
C, Synaptophysin.
D, This tumor was prolactin immunoreactive.
The overall “neuroendocrine” nature of the tumor can be supported by these immunohistochemistry studies.

Malignant Neoplasms of the Nasal
Cavity and Paranasal Sinuses

SQUAMOUS CELL CARCINOMA
Definition:
• Malignant neoplasm of squamous epithelial
cells.
Incidence and Location
• Most common malignant neoplasm of sinonasal
tract representing, 60% to 70% of sinonasal
tract carcinoma
• Paranasal sinuses: maxillary sinus , ethmoid
sinus
• Nasal cavity: lateral nasal wall and nasal septum.
Gender and Age Distribution
• Male : female (2:1) 6th to 7th decades.
Gross Findings:
• Exophytic, friable, necrotic, and ulcerated mass
• Local soft tissue infiltration and bony
destruction

Nasal Cavity
• Well-differentiated, keratinizing (80% to 85%)
• Squamous pearls, intercellular bridges,
hyperchromatic nuclei
Paranasal Sinus
• Moderately to poorly differentiated,
nonkeratinizing
• Spindle cell, papillary, endophytic, verrucous
types recognized.
• Pseudoepitheliomatous hyperplasia,
Schneiderian papilloma, squamous papilloma,
oropharyngeal carcinoma.
Immunohistochemical Features
• Positive with CK5/6, CK8, CK13, p63
• Negative with CK10

Non-keratinizing squamous cell sinonasal
carcinoma of“transitional” type.
High power views of sinonasal keratinizing
squamous cell carcinoma.

SINONASAL TRACT ADENOCARCINOMA
Definition:
• Salivary gland–type adenocarcinoma arising
from mucoserous glands (60%)
• Non–salivary gland–type adenocarcinoma
arising from respiratory mucosa
• Second most common carcinoma of sinonasal
tract 15% of sino-nasal tract carcinomas.
• Para-nasal sinuses > nasal cavity
Gender and Age Distribution
Salivary Gland–Type Adenocarcinoma
• Equal gender distribution
• 3rd to 8th decades, mean: 55 years
Non–Salivary Gland–Type Adenocarcinoma
• Male >>> female (specifically with industrial
exposure)
• 5th to 7th decades.
• Intestinal-type has very strong association with
wood workers and leather workers (500x
increased incidence)
Tumor cells predominantly form tubules with
abundant hyalinized stroma. Some cribriform
pattern is present.

Gross Findings:
• Large, firm, solid, submucosal mass.
• Fungating, ulcerated, and friable mass, often
mucoid to translucent.
• Adenoid cystic carcinoma most common, with
cribriform and cystic pattern, small basaloid
cells with hyperchromatic nuclei
• Intestinal and nonintestinal types
• Papillary, colonic, solid, mucinous, and mixed
types
• Usually tall, non-ciliated, columnar cells, mucin
producing
• Tumor grade determines nuclear features
• Frequently have background of necrosis and
inflammation

Tumor cells within an intestinal-type
adenocarcinoma (ITAC) demonstrate stratification,
elongation, hyperchromasia, and mucinous
differentiation. Note the mitoses.
Stratified nuclei with mild nuclear atypia and
Paneth cells (showing abundant granular
eosinophilic cytoplasm) in an ITAC.

• Metastatic colon carcinoma, Schneiderian papilloma, hamartoma, lymphoma, olfactory
neuroblastoma
• Intestinal types are CK7, CK20, CDX-2, villin, mCEA, MUC2 and MUC5 positive.
• Non-intestinal types are CK7 and S100 positive, but negative for CK20, CDX-2, villin, and
MUCs
• p53, EGFR, and RAS mutation provide prognostic value

Intestinal-type : CK20 (A) and CDX-2 (B)
Nonintestinal adenocarcinomas: positive with CK7 (C) and may show a strong reaction with S100
protein (D).

SINONASAL UNDIFFERENTIATED
CARCINOMA (SNUC)
Definition:
• High-grade aggressive undifferentiated
carcinoma with extensive local disease, lacking
squamous and glandular differentiation
• M > F (2 to 3:1) mean: 6th decade
• Mortality of 80% in 5 years
• Hypercellular tumor arranged in nests, lobules,
and sheets of undifferentiated cells (no
squamous or glandular differentiation)
• Polygonal cells with high nuclear:cytoplasmic
ratio with medium to large nuclei and single,
variable nucleoli
• High mitotic activity
• Tumor necrosis, lymphovascular invasion,
perineural invasion are common
• Usually pan-keratin, CK7, CK8, CK19 positive
• Occasionally EMA, NSE, p53, p63
chromogranin/synaptophysin positive.
• Rarely is S100 protein and CD99 positive

NASOPHARYNGEAL CARCINOMA
• Malignant neoplasm arising from the nasopharynx mucosa showing evidence of
squamous differentiation.
Gender, Race, and Age Distribution
• Male > female (3:1),Asians > Africans > Arctic natives
• Peak, 40 to 60 years
Clinical Features:
• Nasal obstruction, epistaxis, hearing loss, tinnitus, postnasal drip, cranial nerve involvement
• Endoscopy may show mass or fullness
• Strong association with Epstein-Barr virus and high levels of volatile nitrosamines in food
Gross Findings:
• Superior or lateral wall mass, especially fossa of Rosenmüller
• Cervical metastases common finding.
• Positive : with pan-keratin, CK5/6, 34bE12, p63, EBER in situhybridization
• Negative: CK7, CK20, and p16

Loosely cohesive tumor cells are intermingled
with small lymphocytes in this nonkeratinizing
carcinoma. The tumor cells have large round to
oval nuclei, prominent nucleoli, and ill-defined
cell borders. There is a nearly 1:1 ratio of
lymphoid cells to epithelial cells.
Nonkeratinizing Carcinoma (85%)
• Most common type with possible surface
involvement
• Solid sheets, islands, and nests with intimate
lymphoid infiltrates
• Syncytial, large cells with indistinct borders,
vesicular nuclei with prominent, eosinophilic
nucleoli, and scant cytoplasm
• Prominent mitotic figures; necrosis
Keratinizing Squamous Cell Carcinoma (14%)
• Invasive carcinoma with obvious squamous
differentiation and keratinization
• Distinct tumor borders, intercellular bridges
• Frequent surface involvement
Basaloid Squamous Cell Carcinoma(<1%)
• Identical to basaloid squamous cell
carcinoma in other head and neck sites
(rare).

Differentiated Non-keratinizing
nasopharyngeal carcinoma.
Undifferentiated nasopharyngeal carcinoma
composed of tumor cells arranged in compact nests
(so-called Regaud-type growth pattern)

pan-keratin (A);
CK5/6(B) which reveals strong membrane reaction;
p63 (C) nuclear stain in the epithelial component; and strong and diffuse nuclear
Epstein-Barr encoded RNA (EBER) reaction (D).

Undifferentiated NPC
 Can beseen in pediatric age group also.
 2 patterns of growth are:
1. Regaud type characterised by well defined aggregates of tumor cells surrounded by fibrous
tissue and lymphoid cells
2. Schmincke type-Neoplastic epithelial cells grow diffusely & are closely intermingled
with inflammatorycells.
Misnomer- “Lymphoepithelioma”
Tumorcells characteristically show large & vesicular nuclei
with a smooth outline & a single eosinophilicnucleoli

NUT carcinoma
Definition: NUT carcinoma is a poorly differentiated carcinoma (often with
evidence of squamous differentiation) defined by the presence of nuclear
protein in testis (NUT) gene (NUTM1) rearrangement.
Etiology:
The etiology is unknown. There is no association with HPV, EBV, other viral
infection; smoking; or other environmental factors.
Prognosis: Prognosis is poor, with a median overall survival of 9.8 months

A) Sheets of moderate-sized monomorphic poorly differentiated epithelioid cells have pale to
clear glycogenated cytoplasm; and necrosis and mitoses are invariably present.
B ) Abrupt keratinization can appear as a discrete island within a sea of poorly differentiated cells.
C) FISH demonstrates NUT rearrangement when red and green probes flanking the NUT locus are
split apart; the red and green signals together are the normal NUT allele.
D) Diffuse, nuclear immunohistochemical staining with the NUT antibody is diagnostic of NUT
carcinoma; the speckled pattern is characteristic but not always this distinct.

MALIGNANT MUCOSAL MELANOMA
Definition:
• Malignant neoplasm of neural crest–derived melanocytic cells.
• <1% of all melanomas and <5% of all sinonasal tract neoplasms
• Anterior nasal septum > maxillary sinus.
• Increased incidence in Japanese patients
• Usually 5th to 8th decades
Clinical Features:
• Polyp, nasal obstruction, epistaxis, or nasal discharge
• Pain uncommon
Prognosis and Treatment
• Generally poor prognosis (17% to 47% 5-year survival).
• Recurrences common
• Poor prognosis with advanced age, tumors <3 cm, mixed anatomic sites, vascular invasion
• Radical surgery with palliative radiation.

Gross Findings:
• Gray, brown, or black bulky mass with
friable or gelatinous appearance.
• Junctional activity and epidermal
migration confirm primary
• Epithelioid, small, spindle, and
pleomorphic cell types
• Peritheliomatous growth is unique, often
associated with necrotic tumors
• Usually large cells with high
nuclear:cytoplasmic ratio, prominent
nucleoli, intranuclear cytoplasmic
inclusions
• Pigment may be present.
• Mitotic figures are easily identified.

The surface respiratory epithelium shows an
increased number of atypical melanocytes, a finding
helpful in the diagnosis of a primary malignant
mucosal melanoma
A melanoma in situ shows full-thickness
involvement by the pigmented neoplastic
melanocytes.

Arranged in a number of different patterns as well as showing a number of different cell types.
A, Tight fascicles of spindle cells comprise this melanoma.
B, A polygonal-epithelioid appearance to this melanoma.
C, A whorled to meningothelial pattern with mitotic figure.
D, Pleomorphic plasmacytoid cells with intranuclear cytoplasmic inclusions.
E, Pigment can be seen, present in a spindle cell type.
F, An undifferentiated solidsheet of cells comprises this melanoma.

A), Remarkably plasmacytoid differentiation in this melanoma, showing binucleation and
intranuclear inclusions.
B), Rhabdoid cells with abundant, opaque eosinophilic cytoplasm are seen in this melanoma.
C), Prominent, eosinophilic nucleoli.

S100 protein (A),
Melan A (B)
HMB45 (C and D) to a variable degree, ranging from strong, diffuse, and heavy reactions to light,
granular, and sparse reactivity.

OLFACTORY NEUROBLASTOMA
Definition:
• Malignant neuroectodermal neoplasm arising from olfactory epithelium.
• Approximately 2% to 3% of sinonasal tract malignancies
• About 0.4/1,000,000 population
• Bimodal distribution: peak at 11 to 20 and 51 to 60 years, respectively
Gross Findings:
• Polypoid, glistening, soft, vascular masses high in the nasal cavity and ethmoid region.

• Circumscribed lobule separated by vascularized
stroma is maintained to some degree in all
grades.
• Tumor cells form solid nests, Homer Wright
pseudorosettes with neurofibrillar matrix (30%),
and Flexner-Wintersteiner–type true rosettes
with glandular lumen (5%)
• Cells are syncytial, uniform and small, with
round nuclei and “salt-and-pepper” nuclear
chromatin.
• High-grade tumors have larger tumor cells,
nuclear pleomorphism, and increased mitotic
activity; neurofibrillary matrix is scant or absent
• Neuron-specific enolase, chromogranin,
synaptophysin, CD56 positive in 80% of tumors
• S100 protein–positive cells confined to the
periphery of tumor nests
Well-formed lobules of closely packed cells
separated by a highly vascularized stroma make up
this olfactory neuroblastoma.

A large pseudorosette (Homer Wright) shows a
central area of neurofibrillary matrix.
The columnar tumor cells form the glandular
spaces of a true Flexner-Wintersteiner rosette.

The lobules of tumor are separated by fibrosis. Note
the slightly more granular nuclear chromatin that is
seen in a grade 2 tumor.
A grade 3 olfactory neuroblastoma showing a true
Flexner-Wintersteiner rosette and increased mitotic
figures.

A),synaptophysin diffuse expression .
B), S100 protein immunohistochemistry is only positive in cells at the periphery of tumor nests,
indicative of Schwannian cell differentiation.
C), Neuron-Specific Enolase strong and diffuse.
D), CD56 highlights nearly all of the cells in a membranous distribution.

EXTRANODAL NK/T-CELL LYMPHOMA,
NASAL TYPE
Definition:
• Malignant NK/T-cell lymphoma with the bulk
of the disease in the sinonasal tract.
• Most common nonepithelial malignancy of
the sinonasal tract.
• About 10% to 15% of all non-Hodgkin
lymphomas
• Nasal cavity and paranasal sinuses
concurrently affected.
• Male >female (3:1)
• Peak in 6th decade
• Very strong association with Epstein-Barr
virus.
Prognosis and Treatment:
• Overall prognosis is 30% to 50%
• Relapse/recurrences develop in up to 50%

A young female with a clinical
diagnosis of lethal midline granuloma.
Same patient a few years later. There was no
evidence of systemic disease at the time. This
unfortunate individual died a few weeks after this
second photograph was taken.

• Early disease difficult to detect in
background reactive lymphoid
infiltrate
• Diffuse infiltrate that is frequently
angiocentric and angioinvasive
associated with tumor necrosis
• Variable, mixed small and large
lymphoid cells
• May occasionally have extensive
pseudoepitheliomatous
hyperplasia of the epithelium
A mixed population of inflammatory cells
harboring the atypical lymphoid elements
disease has progressed.

Necrosis is noted between islands of atypical
lymphoid cells and prominent arteries.
More cytologically atypical lymphoid cells, easier
to identify after the disease has progressed.

A, The neoplastic cells within this vessel are strongly and diffusely immunoreactive with CD3
B, The neoplastic cells show a positive granzyme reaction.
C, Nearly all of the cells are strongly and diffusely positive with EBER by in situ hybridization.

Rhabdomyosarcoma
• Malignant neoplasm with skeletal muscle
phenotype
• About 20% of rhabdomyosarcomas
involve sinonasal tract
• Nasopharynx more commonly involved
than sinonasal tract.
Age: childhood/young adults (embryonal
subtype); Adults (alveolar subtype)
• Overall mortality between 44% and 69%,
depending on age, histologic subtype, and
stage Combined multimodality therapy
(chemotherapy, radiotherapy, surgery)
Gross:
Large, bulky, fleshy, polypoid, grape-like
masses, simulating polyps
This macroscopic image demonstrates The
similarity between Sinonasal Polyps and
rhabdomyosarcoma.

• Embryonal type (80%):
Round to spindled primitive
mesenchymal cells with
hyperchromatic nuclei;
rhabdomyoblasts with cross-
striations rare; myxoid stroma
may be present.
• Alveolar type (20%):
Fibrous septa separating
loosely cohesive
rhabdomyoblasts into alveolar
spaces; multinucleated giant
cells may be present
Alveolar rhabdomyosarcoma has tumor cells
that form dilated alveolar spaces. Note the
dilapidated wall appearance.

A, Rhabdomyoblasts with elongated and spindled cells.
B, Predominantly primitive appearing cells with abundant, eccentrically
placed eosinophilic cytoplasm.
C, Strap cells with cross striations are very uncommon.

A) A strong desmin immunoreaction is noted in the cytoplasm of this embryonal type
rhabdomyosarcoma in both spindled and epithelioid areas.
B) CD56 shows a strong and diffuse membranous reaction.
C) MYOD1( myoblast determination protein-1) stains nearly all tumor nuclei strongly.
D) Myogenin stains the nuclei in this alveolar rhabdomyosarcoma.

EWING SARCOMA
Definition:
• High-grade, primitive neuroectodermal
neoplasm
• Rare (2/1,000,000 children/year)
• About 20% occur in head and neck with ,20%
arising in sinonasal tract Maxillary sinus >
nasal fossa
Gender and age Distribution:
• Slight male predominance
• Most common in children and young adults
Clinical Features
• Pain, mass, and obstruction
Gross Findings:
• Often polypoid and multilobular, gray-white,
glistening tumor with ulceration and
hemorrhage
• Bone erosion/destruction is common in this
large tumor (up to 6 cm).

• Dense, solid sheets of small- to medium-sized
monotonous cells.
• High nuclear to cytoplasmic ratio with round
nuclei
• Fine nuclear chromatin distribution, small
nucleoli
• Mitotic activity is high with coagulative tumor
necrosis common
• Occasionally may have neural differentiation.
• Positive: FLI1 (nuclear), CD99, vimentin; rarely
keratin
• May react with other neural markers (NSE,
synaptophysin, S100 protein, NFP, GFAP,
chromogranin)
Molecular Features:
• t(11;22)(q24;q12) or t(21;22)(q22;q12) most
common
• FISH (fusion or break-apart probe) or PCR
detection
The sheet of medium cells with scant cyto-
plasm demonstrates coagulative necrosis.

Sheets of medium-sized cells without a
specific pattern.
Fine chromatin and small nucleoli
are noted, along with a mitosis.

IHC marker. Squamous
Cell
Carcinoma
Sinonasal
undifferenciated
carcinoma
Malignant
melanoma
Olfactory
neuroblast
ooma
Extranodal
NK/T-Cell
Lymphoma,
Nasal
Rhabdomy
osarcoma
Ewing
Sarcoma/
PNET
CK5/6 + - - - - -- NA
EMA + 50% Rare - - - NA
NSE - 50% - >90% - - +
S100 protein - <15% + + - - Rare
HMB45 - - + - - - -
CD45RB - - - - + - -
CD56 - - - + + - Rare
CD99 - <10% - - - Rare >99%
Vimentin - - + - + + +
Desmin - - - - - + -
In situ EBER - - - - 100% - -
Chromogranin/
synaptophysin
- >15% - >90% - - +

Take home message…
• Sino-nasal tract lesions are common in Saurashtra region.
• Benign lesions are more common as compared to malignant
lesions.
• Incidence of mucormycosis infection in sino-nasal tract has
increased in COVID-19 patients.
• FNAC is not a preferred tool to investigate sino-nasal mass.
• IHC play very important role to reach final diagnosis.

References:
• Rosai & Ackerman Surgical pathology (1st south asian edition).
• Robbins & cotran pathologic basis of disease (8thedition).
• Head and neck pathology Foundations in diagnostic pathology (2nd
edition).
• David J Dabbs Diagnostic immunohistochemistry (3rd edition).
• Wheater`s functional histology(6th edition).

Sinonasal tract pathology(histopathology)

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