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PubMed Search: Breast polymorphous carcinoma

Emily S. Reisenbichler, M.D.
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Cite this page: Reisenbichler ES Polymorphous. website. Accessed July 6th, 2022.
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

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 style 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 style answer #1
B. Like many of the salivary gland-like tumors of the breast, polymorphous adenocarcinoma is a triple negative, basal-like tumor. Unlike the poor prognosis seen in many triple negative breast tumors, salivary gland-like tumors, including polymorphous adenocarcinoma, may have a more favorable prognosis. (Appl Immunohistochem Mol Morphol 2013;21:283)

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Reference: Polymorphous carcinoma
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