Adenoid cystic carcinoma

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Adenoid cystic carcinoma, abbreviated AdCC, is a malignant tumour commonly seen in the salivary gland.

Adenoid cystic carcinoma
Diagnosis in short

Adenoid cystic carcinoma. H&E stain.

LM cribriform architecture (other patterns: solid, cords, (bilayered) tubules), cystic spaces filled with basophilic material, scant cytoplasm in most cells, nucleus - small, hyaline stroma
LM DDx pleomorphic adenoma
Site salivary gland, breast, lung

Signs mass

General

  • Common malignant neoplasm of salivary gland.
  • AKA cylindroma.[1]
  • Composed of ductal cells and myoepithelial cells; myoepithelial cells > ductal cells.

Microscopic

Features:

  • Cribriform architecture or pseudoglandular spaces (classic pattern) - important feature.
    • Other patterns: solid, cords, (bilayered) tubules.
    • Cystic spaces filled with basophilic material (that is PAS +ve) - key feature.
  • Scant cytoplasm in most cells (myoepithelial cells) - clear/eosinophilic.
    • Moderate eosinophilic cytoplasm in the (rare) ductal cells.
  • Nucleus - small.
    • May be angulated (carrot-shaped) - myoepithelial cells; round/ovoid in ductal cells.
  • Hyaline stroma.

Memory device:

  • AdCC - mostly DNA (scant cytoplasm), distinct nucleus (carrot-shaped).

Notes:

DDx:

Images

www:

Grading

Based on solid component:

  • Low grade = tubules and cribriform structures only; no solid component.
  • Intermediate grade = solid component <30%.
  • High grade = solid component >=30%

Stains

Special stains:

  • PAS +ve material - cystic spaces.[2]

IHC

Features:[3]

  • CD117 +ve.
  • Cyclin D1 +ve.
  • Myoepithelial markers (e.g. calponin, actin) +ve.
    • Typically -ve in PLGA.

Molecular

Features:[4]

  • t(6;9) MYB-NFIB.
    • Seen in ~50% of cases.
    • Worse prognosis if present, esp. if fusion assoc. with transcription.

See also

References

  1. Chest. May 1957. Vol. 31. No. 5. PP. 493-511. http://www.chestjournal.org/content/31/5/493.abstract
  2. URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970070-5. Accessed on: 12 May 2011.
  3. 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.
  4. Mitani, Y.; Rao, PH.; Futreal, PA.; Roberts, D.; Stephens, P.; Zhao, YJ.; Zhang, L.; Mitani, M. et al. (Oct 2011). "Novel Chromosomal Rearrangements and breakpoints at the t(6;9) in Salivary Adenoid Cystic Carcinoma: association with MYB-NFIB chimeric fusion, MYB expression, and clinical outcome.". Clin Cancer Res. doi:10.1158/1078-0432.CCR-11-1870. PMID 21976542.