Polymorphous adenocarcinoma

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Polymorphous adenocarcinoma
Diagnosis in short

Polymorphous adenocarcinoma. H&E stain.

LM low-grade cytology - nuclei ovoid & small, small nucleoli, powdery chromatin (papillary thyroid carcinoma-like appearance); eosinophilic cytoplasm; variable architecture - often small nests, classically has whorling ("eye-of-storm") pattern and single file pattern
LM DDx adenoid cystic carcinoma, pleomorphic adenoma, cribriform adenocarcinoma of the minor salivary gland
IHC S-100 +ve, CK7 +ve, vimentin +ve
Site oral cavity, salivary gland

Prevalence uncommon (varies by study)
Prognosis good

Polymorphous adenocarcinoma, abbreviated PAC, is a rare malignant salivary gland tumour.

It was previously known as polymorphous low-grade adenocarcinoma, abbreviated PLGA.[1]

General

  • Female:male ~= 2:1.
  • Older people ~50-70 years old.
  • Large variably in the prevalence reported - suggests a lacking of reproducibility in the diagnosis.[2]
  • Slow growing - metastases rare - prognosis good.[3][4]

Gross

Microscopic

Features:[6]

  • Architecture: often small nests, may be targetoid.
    • Classically has whorling with eye-of-storm & single file.
  • Cytologically monotonous (uniform) with variable architecture - key feature.
  • Indistinct cell borders.

Note:

  • Always a low-grade tumour - by definition.

DDx:

Images

IHC

Features:[2]

  • S-100 +ve.
  • CK7 +ve.
  • Vimentin +ve.

Others:

  • GFAP +ve/-ve.
  • BCL2 +ve/-ve.
  • Generally negative for myoepithelial markers (calponin, actin) - useful if negative.

See also

References

  1. "Polymorphous adenocarcinoma of the salivary glands: reappraisal and update". Eur Arch Otorhinolaryngol 275 (7): 1681–1695. July 2018. doi:10.1007/s00405-018-4985-5. PMID 29761209.
  2. 2.0 2.1 de Araujo, VC.; Passador-Santos, F.; Turssi, C.; Soares, AB.; de Araujo, NS. (2013). "Polymorphous low-grade adenocarcinoma: an analysis of epidemiological studies and hints for pathologists.". Diagn Pathol 8: 6. doi:10.1186/1746-1596-8-6. PMID 23320410.
  3. 3.0 3.1 Paleri, V.; Robinson, M.; Bradley, P. (Apr 2008). "Polymorphous low-grade adenocarcinoma of the head and neck.". Curr Opin Otolaryngol Head Neck Surg 16 (2): 163-9. doi:10.1097/MOO.0b013e3282f70441. PMID 18327037.
  4. Fife, TA.; Smith, B.; Sullivan, CA.; Browne, JD.; Waltonen, JD.. "Polymorphous low-grade adenocarcinoma: a 17 patient case series.". Am J Otolaryngol 34 (5): 445-8. doi:10.1016/j.amjoto.2013.03.012. PMID 23618791.
  5. Andreu-Barasoain, M.; Vicente-Martín, FJ.; Gómez de la Fuente, E.; Salamanca-Santamaría, J.; Pampín-Franco, A.; López-Estebaranz, JL. (2013). "Polymorphous low-grade adenocarcinoma in the upper lip: a well-described but infrequently recognized tumor.". Dermatol Online J 19 (8): 19265. PMID 24021444.
  6. Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 74. ISBN 978-0781765275.
  7. Skalova, A.; Sima, R.; Kaspirkova-Nemcova, J.; Simpson, RH.; Elmberger, G.; Leivo, I.; Di Palma, S.; Jirasek, T. et al. (Aug 2011). "Cribriform adenocarcinoma of minor salivary gland origin principally affecting the tongue: characterization of new entity.". Am J Surg Pathol 35 (8): 1168-76. doi:10.1097/PAS.0b013e31821e1f54. PMID 21716087.
  8. Curran, AE.; White, DK.; Damm, DD.; Murrah, VA. (Feb 2001). "Polymorphous low-grade adenocarcinoma versus pleomorphic adenoma of minor salivary glands: resolution of a diagnostic dilemma by immunohistochemical analysis with glial fibrillary acidic protein.". Oral Surg Oral Med Oral Pathol Oral Radiol Endod 91 (2): 194-9. doi:10.1067/moe.2001.111306. PMID 11174597.