Breast malignant, children, males
Rare subtypes, WHO classified
Polymorphous carcinoma

Author: Emily S. Reisenbichler, M.D. (see Authors page)

Revised: 8 February 2018, last major update January 2018

Copyright: (c) 2003-2018,, Inc.

PubMed Search: Breast polymorphous carcinoma

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Cite this page: Reisenbichler, E.S. Polymorphous carcinoma. website. Accessed January 23rd, 2019.
Definition / general
  • Primary breast tumor with morphology similar to that of polymorphous low grade adenocarcinoma of the salivary glands
  • "Low grade" terminology not used in these tumors due to reported case with widespread metastases
Essential features
  • Very rare tumor; only 3 reported cases, first described in 2006 (Virchows Arch 2006;448:29)
  • Similar to tumors of the salivary glands; they are composed of monotonous cells arranged in nests and cords
  • Difficult to know prognosis of such a rare tumor but shows slow, aggressive growth with metastatic potential
Clinical features
  • The rare reported cases all presented as:
    • Palpable masses
    • 1.5 - 4 cm in greatest dimension (mean 3 cm) with infiltrative borders
    • Patient mean age 55 (range 37 - 74)
    • No axillary metastases reported but one patient developed distant metastases within 3 years
  • All reported cases were treated with surgical resection (plus radiotherapy if breast conserving surgery) and axillary dissection
Microscopic (histologic) description
  • Monotonous proliferation of neoplastic cells arranged in varying architectural patterns including tubules, trabeculae, alveolar, cribriform and solid nests
  • Nuclei are round to ovoid with vesicular chromatin, moderate mitotic activity without necrosis
  • Central and peripheral areas of the tumor may demonstrate differing architectural and immunohistochemical features
Microscopic (histologic) images

Images hosted on PathOut server:

Images contributed by Emily S. Reisenbichler, M.D.
Missing Image

Salivary gland equivalent polymorphous low grade adenocarcinoma

Positive stains
Negative stains
Differential diagnosis
  • Adenoid cystic carcinoma: both have cribriform and alveolar growth with possible basal lamina-like material and are triple negative (ER / PR / HER2)
    • Adenoid cystic carcinoma has two cell types with a population of actin positive cells that are absent in polymorphous adenocarcinoma
  • Invasive lobular carcinoma: both can have single file pattern of growth but polymorphous adenocarcinoma has membranous E-cadherin and is negative for ER / PR and AR
  • Salivary tumor metastatic to the breast: clinical history of a salivary neoplasm
Board review question #1
    What receptor profile is expected in a primary polymorphous adenocarcinoma of the breast?

  1. ER+, PR+, HER2- (Luminal A)
  2. ER-, PR-, HER2- (Basal-like)
  3. ER-, PR-, HER2+ (HER2 positive)
  4. ER+, PR+, HER2+
Board review answer #1
B. Like many of the salivary gland-like tumors of the breast, polymorphous adenocarcinoma is a triple negative, basal-like tumor (Appl Immunohistochem Mol Morphol 2013;21:283). Unlike the poor prognosis seen in many triple negative breast tumors, salivary gland-like tumors, including polymorphous adenocarcinoma, may have a more favorable prognosis.