Acinic cell carcinoma

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Acinic cell carcinoma, abbreviated AcCC, is a rare type of salivary gland cancer. It is also known as acinic cell adenocarcinoma.

It should not to be confused with pancreatic acinar cell carcinoma.

General

  • Malignant neoplasm of salivary gland arising from acinic cells.
  • The relative prevalence of the neoplasm in the various salivary gland reflects the abundance of acinic cells: parotid gland (~80%) > minor salivary glands (~17%) > submandibular glands (~3%).
  • Affects wide age range -- including children.
  • Site affect prognosis (most aggressive to least aggressive): submandibular > parotid > minor salivary.

Gross

  • Tan or reddish.

Microscopic

Features:

  • Sheets of acinic cells with:
    • Abundant finely vacuolated cytoplasm with basophilic granules - key feature.
      • Granules may be focal.
    • Small nuclei stippled chromatin.
  • Scattered intercalcated duct type cells with:
    • Eosinophilic cytoplasm with moderate amount of cytoplasm.
    • Bland nuclei with slightly larger than seen in acinic cells.
  • +/-Peri-tumoural lymphocytes.
  • +/-Glassy extracellular bluish/purple blobs.

Notes:

  • Adipose tissue -- present in the salivary glands -- is absent in AcCC.
  • May focally resemble thyroid tissue.
  • Smaller (characteristic) microvacuoles (unreported in the literature) may be present that have a bubbly appearance and glassy basophilic inclusions.[1]

Memory device:

  • AcCC - lots of "C"s - chromatin stipled, cytoplasm generous.

DDx:

Images

www:

Grading

General:

  • Not prognostic.
  • Done to avoid phone calls from clinician.

Factors Weinreb uses:[1]

Subtypes

  • Oncocytic variant - rare.
  • Clear cell variant - rare.
  • Papillary cystic variant.

Stains

  • PAS +ve.
  • PAS-D +ve.

IHC

  • S-100 -ve.
  • p63 -ve.
    • p63 +ve in mucoepidermoid carcinoma.

There are a bunch of other stains that are touted to be useful (amylase, anti-chymotrypsin, lactoferrin). Weinreb thinks these are not helpful.[1]

EM

See also

References

  1. 1.0 1.1 1.2 IW. 11 January 2011.
  2. Ihrler, S.; Blasenbreu-Vogt, S.; Sendelhofert, A.; Lang, S.; Zietz, C.; Löhrs, U. (2002). "Differential diagnosis of salivary acinic cell carcinoma and adenocarcinoma (NOS). A comparison of (immuno-)histochemical markers.". Pathol Res Pract 198 (12): 777-83. PMID 12608654.
  3. Sun, Y.; Wasserman, PG. (Feb 2004). "Acinar cell carcinoma arising in the stomach: a case report with literature review.". Hum Pathol 35 (2): 263-5. PMID 14991547.