Invasive breast carcinoma of no special type and variants


Topic Completed: 1 August 2012

Minor changes: 4 March 2021

Copyright: 2001-2021,, Inc.

PubMed search: oncocytic [title] carcinoma breast

Monika Roychowdhury, M.D.
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Cite this page: Roychowdhury M Oncocytic. website. Accessed October 25th, 2021.
Definition / general
  • Composed of 70%+ oncocytic cells
  • Also called malignant oncocytoma
  • Very rare (< 20 cases reported), usually age 60+ years
Prognostic factors
  • Usually high grade (grade 3)
Case reports
Microscopic (histologic) description
  • Well circumscribed, abundant granular eosinophilic cytoplasm and low grade nuclei with conspicuous nucleoli (Am J Surg Pathol 1998;22:221)
  • Similar to apocrine carcinoma on H&E, but different staining pattern
  • No / rare mitotic figures
Positive stains
Negative stains
Electron microscopy description
  • Numerous mitochondria dispersed throughout cell, occupying 60%+ of cytoplasm
Differential diagnosis
Additional references
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