Breast Carcinoma with Osteoclast-like Giant Cells

Definition

Background carcinoma is otherwise unremarkable
- Most types of carcinoma have been reported
  - Infiltrating ductal most common
  - Lobular, adenoid cystic, cribriform, tubular, papillary also reported
Multinucleated giant cells associated with the carcinoma
- 3-50 nuclei
  - Cytologically bland
    - May have prominent nucleoli
  - No mitotic activity in giant cells
- Usually located in stroma
  - Usually immediately adjacent to nests of carcinoma cells
  - Frequently associated with prominent thin walled vessels and hemosiderin
- Occasionally located within lumens formed by carcinoma cells
Gross appearance frequently spongy and brown/red
Must not have sarcomatous or metaplastic stroma

Richard L Kempson MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342