Salivary glands

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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.

Schematic showing the major salivary glands. (WC)

Normal salivary glands

Types of salivary glands

Types of glands:[1]

  1. Serrous - eosinophilic cytoplasmic granules, acinar arrangement - vaguely resembles the acinar morphology of the pancreas.
  2. Mucinous - light eosinophilic staining.

Identifying the glands

The three main glands:

  1. Parotid:
    • Serous glands - lower viscosity, acini (lobules).[2]
    • Most tumours in this gland are benign.
  2. Submandibular:
    • Serous and mucinous glands.
      • Serous ~90% of gland.
      • Mucinous ~10% of gland.
    • Serous demilunes = mucinous gland with "cap" consisting of a serous glandular component.
  1. 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[5]

Entity Architecture Morphology Cell borders Cytoplasm Nucleus DDx Other Image
Pleomorphic adenoma var. mixed pop.; must include: (1) myoepithelium, (2) mesenchymal stroma, and (3) epithelium (ductal cells) or chondromyxoid stroma var. var. (1) plasmacytoid adenoid cystic carcinoma occ. encapsulated,
mixed pop. of glandular,
myoepithelial and mesenchymal cells
 
PA. (WP)
Warthin tumour papillary,
bilayer
cuboid (basal), columnar (apical) clearly seen eosinophilic, abundant unremarkable sebaceous lymphadenoma AKA papillary cystadenoma lymphomatosum
 
PCL. (WP/Nephron)
Basal cell adenoma var., islands surrounded
by hyaline bands, lesion encapsulated
basaloid subtle scant,
hyperchromatic
granular basal cell adenocarcinoma - -
Canalicular adenoma chains of cells cuboid or columnar subtle scant,
hyperchromatic
granular basal cell adenoma exclusively oral cavity, 80% in upper lip; IHC: p63- (webpathology.com), (webpathology.com)
Sialoblastoma var., islands surrounded
by loose fibrous stroma
basaloid subtle scant, hyperch. granular basal cell adenocarcinoma - -

Malignant tumours

Tabular form - adapted from Thompson[6]

Entity Architecture Morphology Cell borders Cytoplasm Nucleus DDx Other Image
Mucoepidermoid carcinoma cystic & solid epithelioid distinct fuffy, clear,
abundant
nuclei sm. SCC (?) IHC: p63+
 
MEC. (WC)
Adenoid cystic carcinoma (AdCC) pseudocysts,
cribriform, solid,
hyaline stroma
epithelioid subtle scant,
hyperchromatic
small
+/-"carrot-shaped"
pleomorphic adenoma, PLGA Stains: PAS+ (pseudocyst material), CD117+, cyclin D1+
 
AdCC. (WC/Nephron)
Acinic cell carcinoma (AcCC) sheets, acinar (islands) epithelioid clear granular abundant stippled, +/-occ. nucleoli adenocarcinoma not otherwise specified, oncocytoma of salivary gland Stains: PAS +ve, PAS-D +ve; IHC: S-100 -ve, p63 -ve
 
AcCC. (WC/Nephron)
Salivary duct carcinoma glandular, cribriform columnar subtle/clear hyperchromatic columnar metastatic breast carcinoma similar to ductal
breast carcinoma; male>female
 
SDC. (WC/Nephron)
Polymorphous low-grade adenocarcinoma variable, often small
nests, may be targetoid
epithelioid indistinct eosinophilic ovoid & small with
small nucleoli
AdCC minor salivary gland tumour,
often in palate,
cytologically monotonous; IHC: S-100+, CK+, vim.+, GFAP+/-, BCL2+/-
 
PLGA. (WC/Nephron)
Epithelial-myoepithelial carcinoma nests (myoepithelial) with tubules (epithelial) epithelioid not distinct eosinophilic cytoplasm; epithelial: scant; myoepithelial: moderate focal clearing AdCC, pleomorphic adenoma rare
 
EMCa. (WC/Nephron)
Basal cell adenocarcinoma var., islands surrounded
by hyaline bands, lesion not encapsulated
basaloid subtle scant,
hyperchromatic
granular basal cell adenoma rare, usu. parotid gland, may arise from a basal cell adenoma
 
BCA. (WC/Nephron)

DDx

Palate

Benign parotid tumours

Oncocytic tumours

Clear cell tumours

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

Salivary gland mucocele

General

  • Benign.
  • Infected mucocele = mucopyocele.

Microscopic

Features:[7]

  • Granulation tissue-like and pseudocyst-like.
    • Granulation tissue-like:
      • Fibroblasts.
      • Small caliber blood vessels.
      • Histocytes.
      • Neutrophils.
    • Pseudocyst:
      • No epithelial lining.
      • Poorly circumscribed.
  • Pale pink extracellular material (mucous) - key feature.
  • +/-Granulomas.[8]

DDx:

Images

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LESION, LEFT LOWER LIP, EXCISION:
- BENIGN MUCOCELE.

Micro

The sections show a stratified squamous epithelium with a thin layer of parakeratosis, minor salivary glands, and a well-circumscribed cystic lesion.

The cystic lesion has a mildly fibrotic appearing wall, is lined by histiocytes intermixed with rare lymphocytes, and contains mucous and macrophages. No significant nuclear atypia is identified. Mitotic activity is not readily apparent.

Pleomorphic adenoma

Myoepithelioma

Basal cell adenoma

General

  • ~2% of salivary gland tumours.
  • May be multifocal.
  • Usually parotid gland, occasionally submandibular gland.
  • Female:male = ~2:1.
  • May be seen in association with dermal cylindromas in the context of a genetic mutation.[9]
  • Malignant transformation - rarely.

Microscopic

Features:

  1. Basal component.
    • Basophilic cells - key feature.
    • Usu. in nests.
    • Large basophilic nucleus.
    • Minimal-to-moderate eosinophilic cytoplasm.
  2. Stromal cells.
    • Plump spindle cells without significant nuclear atypia - distinguishing feature.
      • Stromal cell nuclei width ~= diameter RBC.
    • Dense hyaline stroma.
  3. Tubular component.
    • Within basal component, may be minimal.
  4. Lesion is encapsulated - key feature.

Notes:

  • No chondromyxoid stroma.
  • Neoplastic cells embedded 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.

DDx:

Images:

IHC

  • Luminal stains +ve: CK7 +ve, CAM5.2 +ve.
  • p63 +ve -- basal component.
  • S-100 +ve -- spindle cells in the stroma.

Canalicular adenoma

Warthin tumour

Sebaceous adenoma

Sebaceous lymphadenoma

Oncocytoma of the salivary gland

  • AKA salivary gland oncocytoma.

Malignant

One approach:

  • Differentiate -- luminal vs. myoepithelial vs. basal (mucoepideroid).

Mucoepidermoid carcinoma

Acinic cell carcinoma

Adenoid cystic carcinoma

See: Adenoid cystic carcinoma of the breast for the breast tumour.

Salivary duct carcinoma

Polymorphous low-grade adenocarcinoma

  • Abbreviated PLGA.

Carcinoma ex pleomorphic adenoma

  • Abbreviated Ca ex PA.

Epithelial-myoepithelial carcinoma

Basal cell adenocarcinoma

Sebaceous carcinoma

It is similar to the tumour found in the skin.

Hyalinizing clear cell carcinoma

See also

References

  1. http://www.lab.anhb.uwa.edu.au/mb140/CorePages/Oral/oral.htm#LABSALIVA
  2. http://www.lab.anhb.uwa.edu.au/mb140/CorePages/Epithelia/Epithel.htm
  3. URL: http://dictionary.reference.com/browse/demilune. Accessed on: 19 August 2011.
  4. URL: http://pathology.mc.duke.edu/research/pth225.html. Accessed on: 19 August 2011.
  5. 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.
  6. 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.
  7. URL: http://emedicine.medscape.com/article/1076717-workup. Accessed on: 6 March 2012.
  8. Seifert, G.; Donath, K.; von Gumberz, C. (Jun 1981). "[Mucoceles of the minor salivary glands. Extravasation mucoceles (mucus granulomas) and retention mucoceles (mucus retention cysts) (author's transl)].". HNO 29 (6): 179-91. PMID 7251405.
  9. Choi, HR.; Batsakis, JG.; Callender, DL.; Prieto, VG.; Luna, MA.; El-Naggar, AK. (Jun 2002). "Molecular analysis of chromosome 16q regions in dermal analogue tumors of salivary glands: a genetic link to dermal cylindroma?". Am J Surg Pathol 26 (6): 778-83. PMID 12023583.
  10. URL: http://moon.ouhsc.edu/kfung/jty1/Com/Com304-3-Diss.htm. Accessed on: 25 October 2011.