Prostatic Basal Cell Carcinoma

Definition

• Malignant epithelial neoplasm of the prostate composed primarily of basaloid cells

Diagnostic Criteria

• 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

Original posting/last update: 6/1/12

Supplemental Studies

Immunohistology

• High molecular weight cytokeratin (HMWCK) and p63 positive vary from negative/rare cells to outer layer only to multiple layers
• Negative cases mostly with large nests and necrosis pattern
• Ki67 >60% associated with aggressive behavior
• Ki67 >20% supports carcinoma over hyperplasia
  • Usually <5% in hyperplasia
• bcl2 expression is not seen in basal cell hyperplasia
• Data from Ali 2007

Clinical

• Only a minority of cases behave aggressively
  • Local recurrence in 20%
  • Metastases in 12%
    • All in cases with large nests with central necrosis
• Extraprostatic extension does not appear to be associated with adverse outcome
• It is not clear that prostatectomy affects outcome
  • Most cases diagnosed on TURP
• Not associated with elevated PSA or PAP

Classification/Lists

Prostatic Carcinomas

• Adenocarcinoma (usual type, acinar)
  • Includes variant patterns:
    • Pseudohyperplastic carcinoma
    • Foamy gland carcinoma
    • Atrophic carcinoma
    • Microcystic carcinoma
    • PIN-like and stratified carcinoma
• Basal cell carcinoma (adenoid cystic)
• Ductal adenocarcinoma
• Intraductal adenocarcinoma
• Mucinous adenocarcinoma
• Signet ring adenocarcinoma
• Small cell carcinoma
• Urothelial/transitional cell carcinoma involving prostatic ducts

Prostatic Benign Lesions/Patterns Simulating Carcinoma

• Adenosis (atypical adenomatous hyperplasia)
• Basal cell hyperplasia
• Clear cell cribriform hyperplasia
• Partial atrophy
• Post-atrophic hyperplasia
• Sclerosing adenosis

Other Lesions

• Atypical small acinar proliferation
• High grade prostatic intraepithelial neoplasia (PIN)

Bibliography

• The entire January 2012 issue of Histopathology is devoted to reviews on prostate cancers:
  • Montironi, R., Scarpelli, M., Mazzucchelli, R., Cheng, L. and Lopez-Beltran, A. (2012), The spectrum of morphology in non-neoplastic prostate including cancer mimics. Histopathology, 60: 41–58.
  • Humphrey, P. A. (2012), Histological variants of prostatic carcinoma and their significance. Histopathology, 60: 59–74.
  • Egevad, L. (2012), Handling of radical prostatectomy specimens. Histopathology, 60: 118–124.
• Two recent reviews in Archives of Pathology:
  • Brian Robinson, Cristina Magi-Galluzzi, Ming Zhou , (2012) Intraductal Carcinoma of the Prostate. Archives of Pathology & Laboratory Medicine: April 2012, Vol. 136, No. 4, pp. 418-425.
  • Lars Egevad, Roberta Mazzucchelli, Rodolfo Montironi , (2012) Implications of the International Society of Urological Pathology Modified Gleason Grading System. Archives of Pathology & Laboratory Medicine: April 2012, Vol. 136, No. 4, pp. 426-434.
• Eble JN, Sauter G, Epstein JI, Sesterhenn IA (Eds): World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs. IARC Press. Lyon 2004.
• Ali TZ, Epstein JI. Basal cell carcinoma of the prostate: a clinicopathologic study of 29 cases. Am J Surg Pathol. 2007 May;31(5):697-705
• Yang XJ; McEntee M; Epstein JI. Distinction of basaloid carcinoma of the prostate from benign basal cell lesions by using immunohistochemistry for bcl-2 and Ki-67. Human Pathology, 1998 Dec, 29(12):1447-50.