Salivary glands
The salivary glands help digest food. ENT surgeons take 'em out and want you to diagnose 'em. Cytopathology of the salivary glands is covered in the Head and neck cytopathology article.
Normal
Types of salivary glands
Types of glands:[1]
- Serrous - eosinophilic cytoplasmic granules, acinar arrangement - vaguely resembles the acinar morphology of the pancreas.
- Mucinous - light eosinophilic staining.
Identifying the glands
The three main glands:
- Parotid:
- Serous glands - lower viscosity, acini (lobules).[2]
- Most tumours in this gland are benign.
- Submandibular:
- Serous and mucinous glands.
- Serous ~90% of gland.
- Mucinous ~10% of gland.
- Serous and mucinous glands.
- Sublingual:
- Mucinous glands.
Other:
- Adipose tissue is found between the glands.
- It increases with age.
Images:
Memory devices:
- The parotid gland vaguely resembles the pancreas.
- Submandibular = glands are mixed.
Overview
Benign tumours
Tabular form - adapted from Thompson[3]
Architecture | Morphology | Cell borders | Cytoplasm | Nucleus | DDx | Other | Image | |
Pleomorphic adenoma | var. | mixed pop.; must include: (1) myoepithelium, (2) epithelium (ductal cells), (3) chondromyxoid stroma | var. | var. | (1) plasmacytoid | adenoid cystic c. | occ. encapsulated, mixed pop. of glandular, myoepithelial and mesenchymal cells |
[1] |
Warthin tumour | papillary, bilayer |
cuboid (basal), columnar (apical) | clearly seen | eosinophilic, abundant | unremarkable | sebaceous lymphadenoma | AKA papillary cystadenoma lymphomatosum | [2], [3] |
Basal cell adenoma | var., islands surrounded by hyaline bands |
basaloid | subtle | scant, hyperchromatic |
granular | basal cell adenoca | - | - |
Canalicular adenoma | chains of cells | cuboid or columnar | subtle | scant, hyperchromatic |
granular | basal cell adenoma | exclusively oral cavity, 80% in upper lip; IHC: p63- | - |
Sialoblastoma | var., islands surrounded by loose fibrous stroma |
basaloid | subtle | scant, hyperch. | granular | basal cell adenoca | - | - |
Malignant tumours
Tabular form - adapted from Thompson[4]
Architecture | Morphology | Cell borders | Cytoplasm | Nucleus | DDx | Other | |
Mucoepidermoid carcinoma | cystic & solid | epithelioid | distinct | fuffy, clear, abundant |
nuclei sm. | ? | IHC: p63+ |
Acinic cell adenocarcinoma (AcCC) | acinar (islands) | epithelioid | clear | granular, generous | stippled, +/-occ. nucleoli | ? | ? |
Adenoid cystic carcinoma (AdCC) | pseudocysts, cribriform, solid, hyaline stroma |
epithelioid | subtle | scant, hyperchromatic |
small "carrot-shaped" |
? | ? |
Salivary duct carcinoma | glandular, cribriform | columnar | subtle/clear | hyperchromatic | columnar | metastatic breast ca | similar to ductal breast carcinoma |
Polymorphous low-grade adenocarcinoma | variable, often small nests, may be targetoid |
epithelioid | indistinct | eosinophilic | ovoid & small with small nucleoli |
? | minor salivary gland tumour, often in palate, cytologically monotonous; IHC: S100+, CK+, vim.+, GFAP+/-, BCL2+/- |
DDx
Palate:
- Polymorphous low-grade adenocarcinoma.
- Adenoid cystic carcinoma.
- Pleomorphic adenoma.
Parotid (benign):
- Pleomorphic adenoma.
- Warthin tumour.
IHC overview
General:
- Usually has limited value.
Specifics:
- Luminal markers: CK7, CK19, CAM5.2 (LMWK).
- Basal markers: p63, HMWK, CK14.
- Myoepithelial markers: calponin, actin.
- Uncommitted: S-100.
Notes:
- p63 and S-100 are sometimes call myoepithelial.
Benign
General DDx:
- Inflammation.
- Neoplasm.
- Ductal obstrution.
Chronic Sialadenitis
General
Etiology:[5]
- Infection.
- Autoimmune (e.g. Sjögren syndrome, systemic lupus erythematosus).
- Other.
Microscopic
Features:
- Fibrosis.
- Non-neoplastic mononuclear inflammatory infiltrate.
Image:
Mucocele
General
- Benign.
Microscopic
Features:
- Ball of mucous.
Pleomorphic adenoma
- Abbreviated PA.
General
Features:
- Very common - approx. 60% of parotid gland tumours.[6]
- May transform into a malignant tumour.
- Other benign salivary gland tumours do not do this.
- Only benign childhood salivary gland tumour of significance.
Weinreb's dictums
- Most common salivary tumour in all age groups.
- Seen in all sites (unlike other benign tumours).
- Recurrence and malignancy risk (unlike other benign salivary gland tumours).
- Any part of a tumour that looks like PA makes it a PA.
Gross
- May be cartilaginous appearing.
Microscopic
Features:[6]
- Proliferation of myoepithelium and epithelium (ductal cells) in mesenchymal stroma.
- Cells in ducts = epithelial.
- Cells not in ducts = myoepithelial.[7]
- Mesenchymal stroma - important feature.
- May be any of following: myxoid, mucochondroid, hyalinized, osseous, fatty.
- Chondroid = specific for PA; can diagnose PA without an epithelial (ductal) component if chondroid is present.
- Myxoid = not specific for PA.
- May be any of following: myxoid, mucochondroid, hyalinized, osseous, fatty.
Notes:
- Mesenchymal stroma not required for diagnosis -- if >5% ducts.[8]
- No chondroid stroma and <5% ductal cells = myoepithelioma.
- Complete excision is often elusive; stating "completely excised" on a surgical pathology report is unwise.
- Look for, i.e. rule-out, poorly differentiated carcinoma: carcinoma ex pleomorphic adenoma.
Memory device: MEC = myoepithelium, epithelium, chondromyxoid stroma.
IHC
- S-100 +ve, SMA +ve, GFAP +ve.
Basal cell adenoma
General
- ~2% of salivary gland tumours.
- May be multifocal.
- Usu. parotid gland, occasionally submandibular gland.
- Female:male = ~2:1.
- May be seen in association with dermal cylindromas in the context of a genetic mutation.
- Malignant transformation - rarely.
Microscopic
Features:
- Basophilic cells.
- Usu. nests; may be bilayered tubules or trabeculae.
Notes:
- No chondromyxoid stroma.
- Chondromyxoid stroma present -> pleomorphic adenoma.
- Neoplastic cells embeded in stroma ("stromal invasion") = basal cell adenocarcinoma.
- Basal cell adenocarcinoma may be cytologically indistinguishable from basal cell adenoma, i.e. "bad" architecture makes it a basal cell adenocarcinoma.
IHC
- Luminal stains +ve: CK7 +ve, CAM5.2 +ve.
Canalicular adenoma
General
- Exclusively oral cavity.
- 80% of lesions on upper lip.
Microscopic
Features:
- Channels - "beading of cell".
- Mucoid/hemorrhagic stroma.
DDx:
- Basal cell adenoma.
IHC
- p63 -ve.
- Basal cell adenoma p63 +ve.
Papillary cystadeoma lymphomatosum
- AKA Warthin tumour.
General
Epidemiology:
- May be multicentric ~ 15% of the time.
- May be bilateral ~10% of the time.
- Classically: male > female -- changing with more women smokers.
- Smokers.
- Old - usu. 60s, very rarely < 40 years old.
Notes:
- No malignant transformation.
- Not in submandibular gland.
- Not in sublingual gland.
- Not in children.
Gross
- Motor-oil like fluid.
- Cystic component larger in larger lesions.
- Small lesions may be solid.
Microscopy
Features:
- Papillae (nipple-shaped structures) with a two rows of pink (eosinophilic) epithelial cells (with cuboidal basal cells and columnar luminal cells) -- key feature.
- Fibrous capsule - pink & homogenous on H&E stain.
- Cystic space filled with debris in situ (not necrosis).
- Lymphoid stroma.
Notes:
- +/-Squamous differentiation.
- +/-Goblet cell differentiation.
DDx:
- Lymphoepithelial cyst.
- Cyst within a lymph node.
Images:
Sebaceous adenoma
Microscopic
Features:
- Benign counterpart of sebaceous carcinoma.
Oncocytoma
General
- No risk of malignant transformation.
- ~1% of all salivary gland tumours.
- Typical age: 60s-80s.
- Associated with radiation exposure.
- Major salivary glands - usu. parotid gland.
Gross
- Golden brown appearance.
Microscopic
Features:
- Like oncocytomas elsewhere.
- Eosinophilic cytoplasm (on H&E stain).
- Due to increased number of mitochrondria.
- Fine capillaries.
- Eosinophilic cytoplasm (on H&E stain).
Notes:
- May have clear cell change.
- Multiple small incidental lesions = oncocytosis - not oncocytoma.
IHC
- p63 +ve focally in nucleus.
Malignant
Approach:
- Differentiate -- luminal vs. myoepithelial vs. basal.
Mucoepidermoid carcinoma
General
- Most common malignant neoplasm of salivary gland.
Microscopic
Features:
- Abundant fluffy cytoplasm - with large mucin vacuoles - key feature.
- Nucleus distorted by mucin vacuole.
- Architecture:[9]
- Cystic - low grade.
- Solid - high grade.
Notes:
- Mucin vacuoles may be rare; in a superficial glance -- it may mimic squamous cell carcinoma.
Images:
- Mucoepidermoid carcinoma 2 (WC).
- Mucoepidermoid carcinoma 3 (WC).
- Mucoepidermoid carcinoma (ouhsc.edu).
Acinic cell adenocarcinoma
- Abbreviated AcCC.
- Common malignant neoplasm of salivary gland.
Features:
- Psammoma bodies(?).
- Abundant cytoplasm.
- Stipled chromatin.
- Acinar architecture (islands of cells).
Memory device:
- AcCC - lots of "C"s - chromatin stipled, cytoplasm generous.
Adenoid cystic carcinoma
General
- Common malignant neoplasm of salivary gland.
- AKA cylindroma.[10]
- Should not be confused with dermal cylindroma (a benign skin tumour).
Microscopic
Features:
- Cribriform architecture.
- Scant cytoplasm.
- Carrot-shaped nucleus.
- Hyaline stroma.
Images: Adenoid cystic carcinoma - Mod. Pathol.
Memory device:
- AdCC - mostly DNA (scant cytoplasm), distinct nucleus (carrot-shaped).
IHC
Features:[11]
- CD117 +ve.
- Cyclin D1 +ve.
Salivary duct carcinoma
Needs work.
- Malignant counterpart of salivary duct adenoma.
Polymorphous low-grade adenocarcinoma
- Classically found in the palate.
- Tumour of the minor salivary glands.
Microscopy
- Cytologically monotonous (uniform) with variable architecture - key feature.
- Architecture: often small nests, may be targetoid.
- Nucleus: ovoid & small with small nucleoli.
- Indistinct cell borders.
- Eosinophilic cytoplasm.
DDx
- Pleomorphic adenoma.
- Adenoid cystic carcinoma.
Carcinoma ex pleomorphic adenoma
- Malignant transformation of pleomorphic adenoma.
- Rare.
- May be subtle.
Microscopy
Features:
- Nests of cells, may from glands, single cells. (???)
Note:
- Adenocarcinoma-like.
Sebaceous carcinoma
- Arises from sebaceous glands
- Sebaceous glands are serous glands and clear on H&E.
See also
References
- ↑ http://www.lab.anhb.uwa.edu.au/mb140/CorePages/Oral/oral.htm#LABSALIVA
- ↑ http://www.lab.anhb.uwa.edu.au/mb140/CorePages/Epithelia/Epithel.htm
- ↑ Thompson, Lester D. R. (2006). Head and Neck Pathology: A Volume in Foundations in Diagnostic Pathology Series (1st ed.). Churchill Livingstone. pp. 295-319. ISBN 978-0443069604.
- ↑ Thompson, Lester D. R. (2006). Head and Neck Pathology: A Volume in Foundations in Diagnostic Pathology Series (1st ed.). Churchill Livingstone. pp. 325-357. ISBN 978-0443069604.
- ↑ URL: http://emedicine.medscape.com/article/882358-overviewhttp://emedicine.medscape.com/article/882358-overview. Accessed on: 10 January 2011.
- ↑ 6.0 6.1 Thompson, Lester D. R. (2006). Head and Neck Pathology: A Volume in Foundations in Diagnostic Pathology Series (1st ed.). Churchill Livingstone. pp. 295. ISBN 978-0443069604.
- ↑ IW. 10 January 2011.
- ↑ IW. 10 January 2011.
- ↑ URL: http://moon.ouhsc.edu/kfung/jty1/opaq/PathQuiz/D2A001-PQ01-M.htm. Accessed on: 19 October 2010.
- ↑ Chest. May 1957. Vol. 31. No. 5. PP. 493-511. http://www.chestjournal.org/content/31/5/493.abstract
- ↑ Sequeiros-Santiago, G.; García-Carracedo, D.; Fresno, MF.; Suarez, C.; Rodrigo, JP.; Gonzalez, MV. (May 2009). "Oncogene amplification pattern in adenoid cystic carcinoma of the salivary glands.". Oncol Rep 21 (5): 1215-22. PMID 19360297.