Breast - nonmalignant
Inflammatory / infectious
Lymphocytic mastitis (mastopathy)

Author: Hind Nassar, M.D. (see Authors page)

Revised: 25 April 2018, last major update April 2010

Copyright: (c) 2002-2018,, Inc.

PubMed Search: Lymphocytic mastitis breast [title]

Cite this page: Lymphocytic mastitis (mastopathy). website. Accessed July 23rd, 2018.
Definition / general
  • Uncommon finding associated with type I diabetes
  • Also called lymphocytic mastopathy, diabetic mastopathy
  • Called sclerosing lymphocytic mastitis / lobulitis if prominent fibrosis
Clinical features
  • Rarely associated with DCIS
  • No increased risk of lymphoma
Radiology images

Images hosted on PathOut server:

Mammogram, courtesy of Dr. Mark R. Wick

Images hosted on other servers:

Various images

Case reports
Gross description
  • Clinically palpable mass, usually subareolar
  • Gray white, smooth cut surface
  • Often bilateral
Microscopic (histologic) description
  • Ill defined lesion of dense intralobular, perilobular and perivascular lymphocytes
  • Also lobular atrophy and sclerosis (keloidal fibrosis), B cell lymphoepithelial lesions, lymphoid follicles with germinal centers
  • Also histiocytes and fibroblasts
  • Epithelioid fibroblasts may be mistaken for carcinoma or granular cell tumor (Mod Pathol 1994;7:49)
  • Variable fat necrosis and noncaseating granulomas
  • No changes in overlying epidermis
Microscopic (histologic) images

Images hosted on PathOut server:

Courtesy of Dr. Mark R. Wick

Perivascular lymphocytic infiltrate sparing lobules

Case of the Week #337:

51 year old diabetic woman - various images

Images hosted on other servers:

Keloid-like fibrosis

Lymphoepithelial lesion

CD20+ / CD3- lymphocytes (B, not T cells)

Various images

Findings in men: periductal lymphocytes and dense collagenous stroma

Type I diabetes for 20 years, 5 cm large, moderately coarse nodes, H&E

Cytology description
  • Clusters of ductal cells, lymphocytes and epithelioid fibroblasts in fragments of dense connective tissue (Acta Cytol 1997;41:1349)
Positive stains
  • B cell markers
Molecular / cytogenetics description
Differential diagnosis