Polymorphous adenocarcinoma

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Polymorphous adenocarcinoma
Diagnosis in short

Polymorphous adenocarcinoma. H&E stain.

Synonyms polymorphmous low-grade adenocarcinoma (obsolete term)

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, p40 -ve, p63 +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:

  • Pretty much always a low-grade tumour.

DDx:

Images

IHC

Features:[2]

  • S-100 +ve.
  • CK7 +ve.
  • Vimentin +ve.
  • p63 +ve (22 of 23 cases[7]).
  • p40 -ve (22 of 23 cases[7]).
    • Useful to differentiate from adenoid cystic carcinoma (AdCC); AdCC is usually p63 +ve/p40 +ve (36 or 47 cases) or p63 -ve/p40 -ve (10 of 47 cases).

Others:

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

See also

References

  1. 1.0 1.1 Vander Poorten V, Triantafyllou A, Skálová A, Stenman G, Bishop JA, Hauben E, Hunt JL, Hellquist H, Feys S, De Bree R, Mäkitie AA, Quer M, Strojan P, Guntinas-Lichius O, Rinaldo A, Ferlito A (July 2018). "Polymorphous adenocarcinoma of the salivary glands: reappraisal and update". Eur Arch Otorhinolaryngol 275 (7): 1681–1695. 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. 7.0 7.1 Atiq A, Mushtaq S, Hassan U, Loya A, Hussain M, Akhter N (October 2019). "Utility of p63 and p40 in Distinguishing Polymorphous Adenocarcinoma and Adenoid Cystic Carcinoma". Asian Pac J Cancer Prev 20 (10): 2917–2921. doi:10.31557/APJCP.2019.20.10.2917. PMC 6982655. PMID 31653135. //www.ncbi.nlm.nih.gov/pmc/articles/PMC6982655/.
  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.