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.

Normal

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.
  3. Sublingual:
    • Mucinous glands.

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
Pleomorphic adenoma var. mixed pop.; must include: (1) myoepithelium, (2) epithelium, (3) chondromyxoid stroma var. var. (1) plasmacytoid adenoid cystic c. occ. encapsulated,
mixed pop. of glandular,
myoepithelial and mesenchymal cells
Warthin tumour papillary,
bilayer		 cuboid (basal), columnar (apical) clearly seen eosinophilic, abundant unremarkable sebaceous lymphadenoma AKA papillary cystadenoma lymphomatosum
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 -
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. ? ?
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

DDx by site

Palate:

  • Polymorphous low-grade adenocarcinoma.
  • Adenoid cystic carcinoma.
  • Pleomorphic adenoma.

Benign

Mucocele

  • Mucous.

Pleomorphic adenoma

Epidemiology

Features:[5]

  • Very common - approx. 60% of parotid gland tumours

Histology

Features:[5]

  • Proliferation of myoepithelium and epithelium in mesenchymal stroma.
  • Mesenchymal stroma - key feature.
    • May be any of following: myxoid, mucochondroid, hyalinized, osseous, fatty.
  • Look for, i.e. rule-out, poorly differentiated carcinoma: carcinoma ex pleomorphic adenoma.

IHC: S-100 +ve, SMA +ve, GFAP +ve.

Basal cell adenoma

  • Basophilic cells.
  • Nests.

Canalicular adenoma

  • Channels.

Papillary cystadeoma lymphomatosum

  • AKA Warthin tumour.
  • Papillae.

Microscopy

  • 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.
  • Cystic space.
  • Lymphoid stroma.

DDx

  • Lymphoepithelial cyst.
    • Cyst within a lymph node.

Sebaceous adenoma

  • Benign counterpart of sebaceous carcinoma.

Oncocytoma

  • Like oncocytomas elsewhere.
    • Eosinophilic cytoplasm (H&E) - due to increased number of mitochrondria.

Malignant

Approach:

  • Differentiate -- luminal vs. myoepithelial vs. basal.

Mucoepidermoid carcinoma

General:

  • Most common malignant neoplasm of salivary gland.

Features:

  • Abundant fluffy cytoplasm - with large mucin vacuole.
  • Nucleus distorted by mucin vacuole.

Images:

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.[6]
    • 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:[7]

  • 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

  • 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

  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. ↑ 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.
  4. ↑ 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.
  5. ↑ 5.0 5.1 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.
  6. ↑ Chest. May 1957. Vol. 31. No. 5. PP. 493-511. http://www.chestjournal.org/content/31/5/493.abstract
  7. ↑ 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.
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