Prostatic Basal Cell Carcinoma

Definition

Malignant epithelial neoplasm of the prostate composed primarily of basaloid cells

Composed primarily of basaloid cells
- Hyperchromatic nuclei and high N:C ratio give an overall dark or blue appearance
- Lumens if present may be lined by eosinophilic cells
Stroma usually desmoplastic or myxoid
Exhibits a variety of architectural patterns, frequently mixed
- Adenoid cystic-like is most common
  - Rounded nests
  - Invaginations of stroma form pseudocribriform pattern
  - Frequent perineural invasion
- Small solid nests with peripheral palisading
  - May form lumens
- Basal cell hyperplastic-like
  - Glands lined by multiple layers of cells
  - Central ductal lumens
  - Infiltrative pattern
- Small tubules with hyalinized luminal rims
  - May have intermingling cords of cells
- Large solid nests
  - May have nuclear atypia and mitotic figures
  - May have central necrosis
  - Most aggressive type
Histologic features that help in distinction from benign basal cell hyperplasia
- Infiltration between benign glands
- Extraprostatic invasion (fat, bladder neck)
- Perineural invasion
- Tubules or nests with lumens lined by eosinophilic cells
- Adenoid cystic pattern
- Desmoplastic or myxoid stroma
- Ki67 >20%
- Strong diffuse bcl2 staining

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