Breast

• Uncommon variant of adenosis with proliferation of epithelial and myoepithelial cells

Images hosted on other servers:

• 17 year old girl with a palpable lump (Turk Patoloji Derg 2017;33:240)
• 35 year old woman with adenomyoepithelial adenosis associated with breast cancer (Springerplus 2013;2:50)
• 46 year old woman with a palpable mass (Breast Care (Basel) 2008;3:427)
• Malignant progression of adenomyoepithelial adenosis of breast (Pathol Int 1994;44:475)

• May form a firm mass with circumscribed or ill defined borders or may be grossly indistinguishable from surrounding fibrotic breast tissue

Contributed by Julie M. Jorns, M.D. and Kristen E. Muller, D.O.

The breast lesion pictured (H&E and p63 IHC, 20x) is most difficult to distinguish from which of the following lesions on core biopsy?


1. Adenomyoepithelioma
2. Invasive ductal carcinoma
3. Microglandular adenosis
4. Phyllodes tumor

A. Adenomyoepithelioma. The pictured lesion is adenomyoepithelial adenosis, an uncommon variant of adenosis with a prominent myoepithelial component. This benign lesion may be difficult to distinguish from adenomyoepithelioma, which forms a circumscribed tumor but has similar microscopic features. Adenomyoepithelial adenosis, like other adenosis variants, may have similar features to microglandular adenosis or low grade invasive ductal carcinoma; however, these lesions lack myoepithelium, which is readily evident in adenomyoepithelial adenosis. Phyllodes tumor is a fibroepithelial neoplasm with dissimilar features, namely stromal proliferation with a resulting leaf-like growth pattern.

Comment Here

Reference: Adenomyoepithelial adenosis