Last revised 28 May 2008
Last major update September 2004
Copyright (c) 2004-2008, PathologyOutlines.com, Inc.
See also Oral cavity and oropharynx
Bold and underlined topics are hypertext links and may open a new window
Primary references, normal anatomy, normal histology, embryology, sebaceous differentiation, saliva
Developmental disorders: heterotopia, polycystic disease
Inflammation: diffuse infiltrative lymphocytosis syndrome, Kimura’s disease, Mikulicz’s disease, necrotizing sialometaplasia, sialadenitis, sialolithiasis, Sjogren’s syndrome, xerostomia
Non-neoplastic tumors/tumor-like conditions: adenomatoid hyperplasia, adenomatous ductal hyperplasia of major salivary glands, amyloidosis, benign lymphoepithelial cyst, choristoma, epidermoid cyst, lymphoid hyperplasia, radiation effect
Epithelial/myoepithelial tumors: general, classification, acinic cell carcinoma, adenocarcinoma NOS, adenoid cystic carcinoma, adenosquamous carcinoma, basal cell adenocarcinoma, basal cell adenoma, canalicular adenoma, clear cell tumors, clear cell carcinoma, cystadenocarcinoma, epithelial myoepithelial carcinoma, giant cell tumor, hybrid carcinomas, inflammatory myofibroblastic tumor, intraductal carcinoma, inverted ductal papilloma, keratocytoma, large cell neuroendocrine carcinoma, lipoadenoma, lymphoepithelioma-like carcinoma, malignant mixed tumor, membranous adenoma, metastases, mucoepidermoid carcinoma, myoepithelioma, oncocytoma, oncocytosis, oxyphilic carcinoma, papillary adenocarcinoma, pleomorphic adenoma, polymorphous low grade adenocarcinoma, salivary duct carcinoma, salivary duct papilloma, sebaceous adenoma/lymphadenoma, sialadenoma papilliferum, signet ring adenocarcinoma, small cell carcinoma, squamous cell carcinoma, Warthin’s tumor
Lymphomas: lymphoma-general, MALT lymphoma, T cell lymphoma
Sarcomas: angiosarcoma, desmoplastic small round cell tumor, hemangioendothelioma, liposarcoma, undifferentiated sarcoma
Other tumors: embryoma, granular cell, lipoma, lipomatosis, melanoma, Rosai-Dorfman disease, schwannoma, sialolipoma
Miscellaneous: TNM staging, grossing, frozen section, fine needle aspiration, features to report
AJCC Cancer Staging Manual (6th Ed)
American Journal of Surgical Pathology (AJSP), January 1999 to Sept 2004
Archives of Pathology and Laboratory Medicine (Archives) January 1999 to Aug 2004
Human Pathology, January 1999 to Aug 2004
Modern Pathology, January 1999 to Sept 2004
Rosai, J: Ackerman’s Surgical Pathology (9th Ed); Mosby-Year Book, Inc., 2004
The 2001 USCAP Long Course, Mod Path 2002;15:298
Johns Hopkins textbook of images
Journal search terms: salivary, parotid, sublingual, submandibular
Please refer to these primary references for more detailed discussions and photographs
Major salivary glands are parotid gland (14-28g), submandibular / submaxillary gland (7-8g), sublingual gland (3g)
Parotid gland
Stensen’s duct (main duct) empties into oral cavity opposite crown of second maxillary molar
Has broad superficial lobe and smaller deeper lobe, with facial nerve usually between both lobes
Submandibular/submaxillary gland
Wharton’s duct empties into floor of mouth on both sides of tongue frenulum
Sublingual gland
Bartholin’s duct empties into floor of mouth on both sides of tongue frenulum
Minor salivary glands
Found in lip, gingival, floor of mouth, check, hard palate, soft palate, tongue, tonsils, oropharynx
Compound exocrine glands with ductal and acinar portions; acinar portion is serous, mucinous or mixed
Acini are lined by luminal cells, which are enclosed by myoepithelial cells
Serous acini: PAS+ intracytoplasmic secretory granules; have basally located intercellular capillaries
Mucous acini: well-rounded, basal nuclei; arranged around empty lumen; produce acid and neutral sialomucins
Myoepithelial cells: surround acini, mediate acinar contraction
Ducts are intercalated, striated and interlobular, all with outer basal cells and inner luminal cells
Intercalated ducts have reserve cells that regenerate acinar tissue and terminal duct system
All epithelium is PSA+
Sebaceous glands are attached to parotid and submandibular ducts (see below)
Parotid gland: serous acini only; contains small lymph nodes near or within the gland
Submandibular/submaxillary gland: predominantly serous but also mucinous acini
Sublingual gland: predominantly mucinous but also serous acini
Minor salivary glands:
von Ebner’s glands of tongue: serous acini only
Palate, base and lateral border of tongue: predominantly mucous acini
Lip, cheek, apex of tongue: mixed serous and mucous acini
Micro images: submandibular gland
Fine needle aspirate - (1) “bunch of grapes” arrangement of acini; (2) ducts and “bunch of grapes” arrangement of acini; (3) normal acini
Ectodermal structures, arise from solid epithelial buds of oral mucosa
Connective tissue diminishes with maturation, as do myoepithelial cells
Parotid buds may penetrate intraparotid lymph nodes; rare with submandibular or sublingual structures
Sebaceous type glands mixed with salivary gland acini
Occurs in 10-40% of normal parotid glands, often in periductal locations in interlobular ducts
Micro: single, isolated sebaceous-type cells within serous or mucinous salivary acini or as fully developed sebaceous glands
Micro images: sebaceous glands replacing serous acini
References: Archives 2004;128:245
Formed by acinar cells
High in amylase if secreted by serous glands; high in sialomucin if secreted by mucous glands
Developmental disorders
Also called ectopia
Normal salivary gland tissue at a site where normally not present
Usually in head and neck
Due to misplacement of salivary gland rests along embryologic pathways of migration during development, or by salivary differentiation of remnants of primitive embryologic structures
Intranodal (periparotid most common) or extranodal
May undergo same pathologic processes as usual salivary gland tissue
Most common neoplasm is Warthin’s tumor
Intranodal
More common than extranodal
In infants, most nodes within/near parotid gland contain salivary gland tissue, usually in medullary portion of node
Frequent but less common in adults
Usually composed of intercalated and intralobular ducts, but also serous type acini and immature ducts
Extranodal
May be high or low in head and neck
High: mandible, mastoid bone, external and middle ear, tonsil, mylohyoid muscle, palatine tonsil, gingiva, pituitary gland, cerebellopontine angle; due to abnormalities in migration of embryonic tissue
Low: related to bronchial pouches in lower neck, thyroid gland or parathyroid gland; most commonly at medial border of right sternocleidomastoid muscle near sternoclavicular joint
Case reports: 53 year old woman with cerebellopontine angle solitary fibrous tumor with ectopic salivary gland tissue (AJSP 2004;28:139)
References: AJSP 2000;24:837
Also called dysgenetic disease
Developmental disorder of females with bilateral gland enlargement
Inflammation
Diffuse infiltrative lymphocytosis syndrome
CD8+ lymphocytic infiltrate associated with HIV
Often involves salivary glands (present in 1-6% of US HIV+ patients vs. up to 50% in Africa)
Also affects lacrimal glands, kidney, muscle, nerve, liver, lung, GI, breast
Graded on 0-4 scale, 0: no infiltrate, 4: 2+ foci of 50 or more mononuclear cells in a 4-mm2 area of a section
Micro: resembles Sjogren’s syndrome; salivary ductal epithelial atypia common in Cameroon in advanced HIV patients
References: Archives 2000;124:1773
Rare chronic inflammatory disorder involving deep subcutaneous tissue of head and neck, often with lymphadenopathy and salivary gland involvement
Usually Asian males with elevated serum IgE and eosinophilia
US study showed 85% males, mean 32 years old, range 8-64 years, affects blacks, whites and Asians; rarely salivary gland involvement (AJSP 2004;28:505)
May clinically simulate a neoplasm
Chronic and indolent; rarely causes death
Treatment: surgery; may recur
Micro: follicular hyperplasia, eosinophilic infiltrates, postcapillary venule proliferation
DD: angiolymphoid hyperplasia with eosinophilia (all ethnic groups, superficial nodules, bleeding, pruritis, normal IgE and no eosinophilia)
Also called benign lymphoepithelial lesion
Presents as slow, bilateral, symmetric enlargement of salivary and lacrimal glands
May subside during acute infections
May be confined to salivary gland, usually part of Sjogren’s syndrome
Increased incidence with HIV
Initially polyclonal, may evolve into lymphoma (diffuse large B cell or SLL/CLL, rarely Hodgkin’s lymphoma, peripheral T cell lymphoma)
Gross: solid gray-white areas and occasional cysts
Micro: marked lymphocytic infiltration with lymphoid follicles surrounding solid epithelial nests (epimyoepithelial islands); also scattered histiocytes and dendritic cells; excess hyaline basement membrane material deposited between cells; also acinar atrophy and destruction, lymphoepithelial lesions, monocytoid B cells; usually no fibrosis, no involvement of large ducts
Reactive condition of minor or occasionally major salivary glands, often hard or soft palate, probably due to ischemia or vasculitis
Gross: ulcerated lesion of hard palate
Micro: ulcerated surface mucosa; intraductal proliferation of metaplastic squamous epithelium containing trapped mucous cells in lobular but noninfiltrative pattern; pseudoepitheliomatous hyperplasia common; vascular proliferation with prominent inflammatory infiltrate and partial necrosis of salivary glands, associated with squamous metaplasia of adjacent ducts and acini
DD: squamous cell carcinoma, mucoepidermoid carcinoma, post-radiation changes
Bacterial, viral or autoimmune
Bacterial
Rare, usually due to obstruction (sialolithiasis); caused by Staphylococcus aureus, Streptococcus viridans, gram negative bacteria
Stones may be due to obstruction of duct orifice by food or trauma-related edema
Also associated with dehydration, malnutrition, immunosuppression
Usually unilateral, painful enlargement of salivary gland; may cause abscess requiring surgical drainage
Chronic sialadenitis
Also called lymphoepithelial sialadenitis (LESA)
Relatively common
Chronic lymphocytic inflammation, often without symptoms
Associated with obstruction (with atrophy and fibrosis), rheumatoid arthritis (older women), Sjogren’s syndrome, sialolithiasis, mumps
50% are monoclonal by PCR, but this is insufficient to diagnose MALT lymphoma without other evidence of malignancy (such as monoclonality by immunohistochemistry or flow cytometry or monocytoid infiltrates in regional lymph nodes)
Micro: markedly hyperplastic lymphoid tissue infiltrates salivary gland with loss of acini; ducts are surrounded by and infiltrated by lymphoid cells
DD: MALT lymphoma (ducts surrounded by broad coronas of monocytoid cells, infiltration of interfollicular region by monocytoid cells or atypical plasma cells containing Dutcher bodies)
References: Mod Path 2002;15:255
Chronic sclerosing sialadenitis
Unilateral; lymphoplasmacytic periductal infiltrate leading to encasement of ducts in thick fibrous tissue
May require surgical excision
Usually due to sialolithiasis and NOT associated with systemic autoimmune disease, although may be due to an immune process (Mod Path 2002;15:845)
Kuttner’s tumor: involvement of submandibular gland
Micro: dilated ducts filled with inspissated secretions, associated lymphoplasmacytic infiltrate with variable germinal centers; late fibrosis and acinar atrophy; sialoliths in 50-80%
Micro images: lymphocytic infiltrate and fibrosis #1; #2 with ductal atrophy
Granulomatous sialadenitis
Due to tuberculosis, sarcoidosis, fungal infections, duct obstruction (may contain mucin pools)
Micro images: fine needle aspirate of sarcoidosis with epithelioid histiocytes, lymphocytes and giant cells #1; #2
Sclerosing polycystic adenosis
Discrete mass, usually in parotid gland, formed by fibrous stroma overlying dilated and hyperplastic ductal and acinar structures
May have apocrine metaplasia and transluminal bridges with cribriform growth
May have prominent atypia
Viral
Often due to mumps (paramyxovirus), usually affects parotids, also pancreas, testes
Also Epstein-Barr virus, coxsackievirus, influenza A, parainfluenza
Micro images: viral sialadenitis
Stones (calculi) within salivary ducts
Most common within submandibular gland (saliva may be more saturated with calcium salts)
Stones may have foreign body or bacterial nidus; also composed of carbonate apatite
Produces swelling of distal salivary gland tissue, then glandular inflammation and induration with destruction of acini
Treatment: surgical removal, disintegration of calculi with shock-wave lithotripsy
Gross images: stone in duct
Micro: dilated ducts with squamous metaplasia, variable chronic inflammatory infiltrate, variable destruction of acini
Micro images: fine needle aspirate - extensive calcification; benign duct obstructive lesion due to sialolithiasis
Xerostomia (dry mouth), keratoconjunctivitis sicca (dry eyes), rheumatoid arthritis, hypergammaglobulinemia
Autoimmune disorder that affects not only salivary glands and lacrimal glands of Mikulicz’s disease, but also minor salivary glands and occasionally lymph nodes, lung, kidney, bone marrow, skeletal muscle, skin, liver
Associated with autoimmune thyroiditis, systemic vasculitis, MALT lymphomas
Variable amyloid deposition outside the salivary glands
Diagnosis: labial gland biopsy
Micro: extensive lymphoid infiltrate with germinal centers, often interstitial fibrosis and acinar atrophy; usually no/rare epimyoepithelial islands in salivary glands, although may appear in skin sweat glands
Dry mouth
Associated with Sjogren’s syndrome
Gross: dry mucosa, atrophy of tongue papillae with fissures, ulcerations
DD: radiation therapy, anticholinergic drugs
Non-neoplastic tumors and tumor-like conditions
Nodular hyperplasia of minor salivary glands
Usually hard palate, also retromolar
Adenomatous ductal hyperplasia of major salivary glands
May coexist with epithelial-myoepithelial carcinoma, chronic parotiditis, other salivary gland tumors
May be precursor lesion to salivary gland tumors
Composed of intercalated duct epithelium
May involve salivary gland as tumor mass (amyloid tumor) or as a systemic disorder
May cause sicca syndrome
Parotid gland or upper cervical lymph nodes
Epithelium may be induced by lymphoid hyperplasia
May be related to branchial cleft cyst, multilocular thymic cyst, Warthin’s tumor
Gross: unilocular or multilocular
Micro: cyst lined by glandular or squamous epithelium and surrounded by prominent lymphoid follicles, which may penetrate cyst lining
HIV associated lymphoepithelial cyst
Resembles benign lymphoepithelial cyst or Mikulicz’s disease or both
Common in HIV+ patients, usually parotid gland, almost always cystic
Cyst epithelium derives from striated ducts
Lymphocytes are polyclonal; usually don’t progress to lymphoma
In children, lesions may be monoclonal and resemble MALT but don’t progress to MALT lymphoma
Micro: lymphocytes may have clear cytoplasm and penetrate epithelium
Micro images: figure E
Gingival nodule of disorganized seromucinous salivary gland tissue mixed with sebaceous glands
Unilocular cystic formation with squamous lining containing a granular layer
Prominent benign lymphoid proliferations, often within intraparotid lymph nodes
Micro images: fine needle aspirate of intraparotid lymph node with lymphocytes and central tingible body macrophages #1; #2
Usually involves submandibular glands (most likely to be in field of radiation for oral cavity tumors)
Gross: firm, swollen glands
Micro: acinar atrophy, chronic inflammatory cells, squamous metaplasia of duct lining cells
Epithelial/myoepithelial tumors
Risk factors: radiation exposure (atomic bomb survivors, radiation therapy, chemoradiation therapy) with mean latency after low dose radiation exposure of 11 years for malignant tumors and 21 years for benign tumors; alcohol and tobacco are NOT risk factors except for Warthin’s tumor (associated with smoking)
Site: most are in parotid gland; sublingual tumors are rare and may be difficult to distinguish from minor salivary gland primary tumors of anterior floor of mouth
Benign: pleomorphic adenoma (50%), Warthin’s tumor (5%), oncocytoma, basal cell adenoma, ductal papilloma
Malignant: mucoepidermoid carcinoma (15%), polymorphous low grade adenocarcinoma (10%), acinic cell carcinoma, adenoid cystic carcinoma, malignant mixed tumor, squamous cell carcinoma (1%)
Bilateral tumors: Warthin’s tumor is most common, also pleomorphic adenoma and acinic cell carcinoma
>90% arise in parotid gland, 5% in submandibular gland, remainder in sublingual or minor salivary glands
Minor salivary gland tumors: usually in hard palate (site with most glandular tissue)
May arise in lymph nodes around salivary glands; deep parotid tumors may present as intraoral masses
15% of parotid tumors are malignant, 40% elsewhere
Children: pleomorphic adenoma most common, but more often malignant; most common malignant tumors are mucoepidermoid carcinoma, adenoid cystic carcinoma, acinic cell carcinoma
Regional lymph nodes: nodal metastases usually evident on initial clinical evaluation; low grade tumors rarely metastasize to regional nodes, high grade tumors often do; nodal involvement tends to be orderly from intraglandular to adjacent nodes to upper and midjugular nodes, and occasionally to retropharyngeal nodes; bilateral nodal involvement is rare
Metastases: usually to lungs
Treatment:
Parotid gland tumors - superficial lobe tumors are treated with superficial / partial parotidectomy with preservation of facial nerve
Total parotidectomy with sacrifice of facial nerve may be necessary if high grade or advanced tumor
Neck dissection necessary if nodal involvement
Submandibular tumors - total excision; often recur because of difficulty of getting good margins due to closeness of mandible
Radiation therapy -for inoperable tumors
Poor prognostic factors: postoperative recurrence, submandibular site, facial nerve paralysis, high grade tumor
Difficult because most tumors arise from or differentiate to epithelial or myoepithelial cells, which can undergo various metaplastic changes (oncocytic, chondroid, squamous, sebaceous)
Subtypes are clustered based on expression of myoepithelial, luminal and basal cell phenotypes (Mod Path 2004;17:803)
WHO classification: stresses distinction between benign and malignant
Diagram: schematic of adenomas
1-3% of salivary gland tumors; #2 childhood salivary gland malignancy after mucoepidermoid carcinoma
Conflicting reports on gender predominance, peaks in 20’s and 40’s
Usually parotid and minor salivary glands, also parotid lymph nodes
10-15% metastasize (usually to local lymph nodes), 10-30% recur (may be due to inadequate excision)
80-90% recur if incompletely excised
5 year survival 90%, 20 year survival 60%
Less aggressive in minor salivary glands
Poor prognostic factors: high stage, pain or fixation, gross invasion, desmoplasia, anaplasia or dedifferentiated component, increased mitotic figures, necrosis, neural invasion, incomplete resection, large size, involvement of deep lobe of parotid
Case reports: dedifferentiation with myoepithelial features after multiple resections (Archives 2002;126:1104), dedifferentiated parotid tumor with facial nerve involvement but no prior surgery (Archives 2004;128:e52), parotid tumors in 35 year old father and his 16 year old daughter (Archives 1999;123:1118)
Gross: encapsulated, tan-gray, firm to soft, solid/cystic; usually < 3 cm; 3% bilateral or multicentric
Micro: variable patterns - solid, microcystic, papillary cystic (associated with hemorrhage), follicular; variable cell types - uniform acinar (serous) type cells with basophilic granular cytoplasm, clear cells (hypernephroid pattern, contains glycogen or mucin), vacuolated, intercalated duct, nonspecific glandular cells (smaller, syncytial); few mitotic figures; may have prominent lymphoid follicles at periphery (lymphoid stroma), psammoma bodies
Micro images: (1) papillary fronds with hobnail cells and vacuolated cells; (2) microcystic and solid patterns in tumors from father and daughter; (3) figure 3A-tumor (left) and normal salivary gland (right); (4) various micro images #1; #2; (5) 1-clear cells representing dedifferentiated tumor with minor component of classic tumor; 2-S100+; 3-smooth muscle actin+; 4-focal AE1-AE3+; (6) 1-dedifferentiated parotid tumor with some classic areas; 2-mitotic figures and necrosis; 3-differentiated areas with basophilic cytoplasm and vesicular nuclei; 4-PAS+ diastase resistant granules; (7) with clear cells; (8) D: H&E; E: CK7; F: CK20; (9) dedifferentiated tumor
fine needle aspirate - acinar-like cells but with larger nuclei, no ducts, no fibrofatty stroma and no “bunch of grades” architecture #1; #2; #3; #4; #5; #6: A: oncocytoma; B: acinic cell carcinoma
Positive stains: keratin, alpha-1-antichymotrypsin, alpha amylase, vasoactive intestinal polypeptide, myoepithelial markers, granules are PAS+ diastase resistant; may have focal neuroendocrine staining
EM: multiple round, electron dense, cytoplasmic secretory granules
DD: normal parotid (tumors lack striated and interlobular ducts, lack lobular architecture), thyroid carcinoma
Adenocarcinoma, not otherwise specified (NOS)
Common, 5-10% of salivary gland tumors
Mean 58 years old, range 10-93 years
Often fixed to skin or deep tissues; palatal lesions often ulcerated and involve bone
Sites: parotid gland, submandibular gland, palate, buccal mucosa
Diagnosis of exclusion (not metastatic, not another salivary gland carcinoma)
Treatment: complete surgical excision
Case reports: 49 year old man with parotid mass (Archives 2004;128:487)
Gross: poorly circumscribed with infiltrative borders; solid tan cut surface with hemorrhage and necrosis
Micro: glandular or ductal differentiation but no features characteristic of other specific types; small clusters of cuboidal, round or ovoid cells with distinct borders and abundant cytoplasm; may have clear cell or oncocytic features; low, intermediate or high grade based on cytomorphic features
Micro images: cellular tumor with glandular or ductlike structures, occasional pink cytoplasmic granules, occasional mucicarmine+ cells; figure 6-smooth muscle actin stains myofibroblasts and stromal cells, not tumor cells
DD: polymorphous low grade adenocarcinoma, metastatic adenocarcinoma, membranous adenoma
Adenoid cystic carcinoma
Formerly called cylindroma
Most common in submandibular, sublingual or minor salivary glands
Also seen in nose, sinus, upper airway
Slow growing but aggressive; 50% metastasize, often silently to lung or bone; recurrences are frequent and often late
5 year survival is 60%, 10 year is 30%, 15 year is 15%
Higher recurrence rates for solid (100%) vs. cribriform (89%) vs. tubular (59%) patterns
15 year survival rates by pattern are solid (5%), cribriform (26%), tubular (39%)
Poorer prognosis for dedifferentiated, p53+ tumors
Better prognosis for tumors of palate or parotid gland
Perineurial invasion may be due to expression of brain derived neutrotrophic factor (Hum Path 2002;33:933)
Treatment: radical surgery regardless of tumor differentiation
Gross: small, solid, poorly encapsulated and infiltrative
Micro: cribriform, solid or tubular pattern similar to cylindromas of skin; small bland myoepithelial cells with scant cytoplasm and dark compact angular nuclei surround pseudoglandular spaces with PAS+ excess basement membrane material and mucin; peripheral perineurial invasion and small true glandular lumina; no squamous differentiation; no extensive necrosis
Note: presence of pseudoglandular lumina, true glandular lumina and perineurial invasion is usually required for diagnosis
Dedifferentiated tumors have irregular tumor islands composed of anaplastic cells with abundant cytoplasm and desmoplastic stroma
Grading: tubular and cribriform patterns are considered low grade/grade 1; 30% to ~70% solid is intermediate grade/grade 2, predominantly solid is high grade/grade 3.
Micro images: (1) figure 4: A-H&E; B-calponin stains myofibroblasts; (3) various images as part of case history; (4) various gross and micro images; (5) classic tumor with cribriform and tubular structures; (6) low grade to high grade; (7) H&E, CK7 and CK20; (8) H&E and CD117 #1; #2; #3; #4
fine needle aspirate - small cells with bland nuclear features forming a pseudoglandular space containing a homogeneous, metachromatically staining hyaline globule #1; #2; #3; #4; #5; #6: fig B/C
Positive stains: cells in ducts - keratin, CEA, alpha-1-antichymotrypsin, S100, CD117/c-kit; cells around pseudoglandular spaces - S100, actin, variable keratin; dedifferentiated tumor - S100
Cytogenetics: loss of heterozygosity at 6q23-25 ( t[6;9][q21-24;p13-23] )
EM: pseudoglandular spaces, intercellular spaces, abundant basal lamina, true glandular lumina; cells are intercalated ducts, myoepithelial, secretory and reserve cells
DD: pleomorphic adenoma (not invasive, no perineurial invasion, has squamous metaplasia and mesenchyme-like areas), polymorphous low grade adenocarcinoma (very rare in major salivary glands, bland uniform cells, CD117 weak/negative)
References: AJSP 1999;23:465, Mod Path 2003;16:1224 (CD117 expression). Mod Path 2002;15:687 (CD117/c-kit)
Dedifferentiated tumors
Rare aggressive variant with death usually within 5 years of diagnosis
Dedifferentiated component either poorly differentiated adenocarcinoma or undifferentiated adenocarcinoma
Micro images: (1) left-classic, right-dedifferentiated tumor; (2) poorly differentiated and undifferentiated tumor; (3) HER2, p53, Rb, Ki-67
References: Mod Path 2003;16:1265
Rare, aggressive
In minor (but not major) salivary glands and ducts
>90% males, mean age 58 years (range 32-99 years)
Sites: tongue, floor of mouth, nasal cavity, larynx
Metastases: in 70-80% even with primaries < 1 cm; variable histology
Treatment: surgical resection with neck dissection
5 year survival: 25%
Gross: 2 mm to 1 cm erythroplakic ulcer or indurated submucosal nodule
Micro: adenocarcinoma, squamous cell carcinoma and mixtures resembling mucoepidermoid carcinoma; may have multifocal carcinoma in situ involving salivary gland ducts, upward extension of intraductal carcinoma to involve mucosal epithelium, glassy squamous cells; commonly perineurial invasion and widespread invasion of submucosa
Micro images: figure A
Positive stains: mucicarmine, PAS with diastase, Alcian blue (pH 2.5 and 1.0)
DD: mucoepidermoid carcinoma, squamous cell carcinoma, pseudoglandular squamous cell carcinoma
Also called basaloid carcinoma
1-2% of salivary gland carcinomas
Malignant counterpart of basal cell adenoma; 23% arise within basal cell adenomas
10-14% are associated with skin adnexal tumor syndrome
Usually parotid gland, ages 50+
37% recur locally, 8% metastasize (solid pattern) to lymph nodes, 4% to lungs; death from disease in unusual
Associated with dermal cylindromas
Treatment: excision with clear margins
Micro: low grade malignancy similar to basal cell adenoma but infiltrative with perineurial invasion and vascular invasion; variable cytologic atypia and mitotic activity; solid, trabecular, tubular or membranous patterns; no myxoid matrix
Micro images: (1) various patterns; (2) H&E and CD117; (3) figure A and morphologically similar tumors
Positive stains: p53, HER2, CD117/c-kit
DD: adenoid cystic carcinoma (true cribriform structures, angular and hyperchromatic nuclei or prominent nucleoli, strong muscle marker staining)
Also called monomorphic adenoma
2% of benign salivary gland tumors
Usually adults, 2/3 female, mean age 58 years; rarely is congenital and resembles embryoma
Parotid gland or periparotid lymph nodes
Benign; rarely transforms, more likely if dermal analogue variant
Usually some myoepithelial differentiation using immunostains (Archives 2000;124:401)
Treatment: excision
Gross: encapsulated, often cystic, relatively small
Micro: solid, trabecular or tubular growth of epithelial