Final Diagnosis -- Basal Cell Carcinoma of Prostate


DISEASE FACT SHEET

Extremely rare malignant neoplasm of prostate arising from basal cells of the prostatic acini or ducts [1]

Approximately 99 cases reported as per PubMed dataset

Epidemiology

Primarily affects elderly men with a wide age range (28-89 years)

Synonyms

Basal cell carcinoma (BCC): resembles BCC of skin
Adenoid cystic carcinoma (ACC): resembles ACC of salivary glands or other sites
Adenoid cystic-like tumor of prostate

Clinical Presentation

Patients present with obstructive urinary symptoms, perianal pain and tend to have normal serum PSA level except in patients with concurrent prostatic adenocarcinoma who tend to have elevated PSA levels

Gross

Tan-white fleshy infiltrative mass with focal micro-cystic areas corresponding to the adenoid cystic morphology seen on histology.

Site: Most BCCs arise in the transitional zone with variable extension into peripheral zone, bladder neck or extra-prostatic adipose tissue.

Histopathology

Basaloid tumor cells with high nuclear cytoplasmic ratio, scant to absent cytoplasm with oval to angulated nuclei. Two main histologic subtypes are BCC pattern and ACC pattern with up to 80% cases showing variable proportion of both patterns [2-3].

Similar to BCC of skin the BCC pattern is characterized by solid nests of basaloid tumor cells with peripheral palisading with or without central necrosis. Similar to ACC of salivary gland or other sites the ACC pattern is characterized by nests of basaloid tumor cells with prominent cribriform architecture with or without surrounding hyaline basement membrane like material. The lumen may contain basophilic secretions.[4-6]

Both patterns are associated with desmoplastic stromal response (important to distinguish from basal cell hyperplasia without desmoplasia) and variable presence of perineural invasion, angiolymphatic invasion, necrosis or extraprostatic extension to involve bladder neck, adipose tissue or seminal vesicle

Rarely other histologic features like sebaceous, or squamous cell differentiation may be present.

Gleason grade

Gleason grading is not applicable for this variant

ANCILLARY TESTS

Immunohistochemistry [7-15]

Basal cell markers: p63+, High molecular weight cytokeratin/HMWCK (34?E12)+

Bcl-2: Strong and diffuse +

Prostate markers: Prostate specific antigen (PSA) -, prostate specific acid phosphatase (PSAP)-, ERG -, androgen receptor (AR) +/-, alpha-methylacyl co-A racemase (AMACR) -/+

Cytokeratin stains: cytokeratin (CK) 7+ and CK 20-: CK7 stains luminal cells in ACC pattern where as CK 7 is negative in pure solid basal cell nests

Neuroendocrine markers: Synaptophysin -/+, chromogranin -

Ki-67: High proliferation index of >20%

Molecular

Negative for t(6;9) MYB-NFIB translocations seen in ACC of salivary, skin adnexa, or lung

No ERG re-arrangements reported [16-17]

Prognosis and treatment

Clinical behavior varied from indolent to aggressive. Certain features like presence of central necrosis, high proliferation index and lack of reactivity for basal cell markers are associated with aggressive clinical behavior.

Local recurrence, metastasis occur in 30-50%

Surgery: TURP or radical prostatectomy

Advanced cases may need adjuvant radiotherapy and chemotherapy

DIFFERENTIAL DIAGNOSES

  1. Basal cell hyperplasia: smaller nests, not infiltrative, maintained lobular architecture, low proliferation index (generally <5%), no perineural or vascular invasion, no desmoplasia, less BCL-2 expression
  2. Poorly differentiated adenocarcinoma of prostate: Prostate carcinomas with basaloid or atrophic morphology sometimes may show aberrant p63 expression
  3. Small cell carcinoma (primary/metastatic): Nuclear molding, salt and pepper chromatin, abundant necrosis, and crush artifact. Positive neuroendocrine markers and negative basal cell markers.
  4. Poorly differentiated urothelial carcinoma: Tumor cells with abundant cytoplasm and marked pleomorphism; positive for p63 or HMWCK like BCC/ACC
  5. Cloacogenic carcinoma of anal canal and ACC of Cowper's gland: Morphologic and immunostain overlap so distinction is based on epicenter of the tumor.

SUMMARY

BCC/ACC of prostate is an extremely rare entity. This case highlights an unusual presentation with hematospermia in a young man with normal serum PSA level along with associated Müllerian duct cyst. Prostate biopsy showed basal cell carcinoma with unusual focal CK20 positivity. Patient was treated with radical prostatectomy given the uncertain potential for local recurrence or distant metastasis.

REFERENCES

  1. McKenney JK, Amin MB, Srigley JR, Jimenez RE, Ro JY, Grignon DJ and Young RH: Basal cell proliferations of the prostate other than usual basal cell hyperplasia: A clinico- pathologic study of 23 cases, including four carcinomas, with a proposed classification. Am J Surg Pathol 28: 1289-1298, 2004.
  2. Iczkowski KA, Ferguson KL, Grier DD, Hossain D, Banerjee SS,McNeal JE and Bostwick DG: Adenoid cystic/basal cell carcinoma of the prostate: Clinicopathologic findings in 19 cases. Am J Surg Pathol 27: 1523-1529, 2003.
  3. Ayyathurai R, Civantos F, Soloway MS and Manoharan M: Basal cell carcinoma of the prostate: Current concepts. BJU Int 99:1345-1349, 2007.
  4. Begnami MD, Quezado M, Pinto P, Linehan WM and Merino M:Adenoid cystic/basal cell carcinoma of the prostate: Review and update. Arch Pathol Lab Med 131: 637-640, 2007.
  5. Ali TZ and Epstein JI: Basal cell carcinoma of the prostate:A clinicopathologic study of 29 cases. Am J Surg Pathol 31:697-705, 2007.
  6. Komura K, Inamoto T, Tsuji M, Ibuki N, Koyama K, Ubai T, Azuma H and Katsuoka Y: Basal cell carcinoma of the prostate:Unusual subtype of prostatic carcinoma. Int J Clin Oncol 15: 594-600, 2010.
  7. X.J. Yang, M. McEntee, J.I. Epstein Distinction of basaloid carcinoma of the prostate from benign basal cell lesions by using immunohistochemistry for bcl-2 and Ki-67 HUM PATHOL, 29 (1998), pp. 1447-1450
  8. Bohn OL, Rios-Luna NP, Navarro L, Duran-Peņa A andSanchez-Sosa S: Basal cell carcinoma of the prostate gland: A case report and brief review of the basal cell proliferations of the prostate gland. Ann Diagn Pathol 14: 365-368, 2010.
  9. Ahuja A, Das P, Kumar N, Saini AK, Seth A and Ray R: Adenoid cystic carcinoma of the prostate: Case report on a rare entity and review of the literature. Pathol Res Pract 207: 391-394, 2011.
  10. Tuan J, Pandha H, Corbishley C and Khoo V: Basaloid carcinoma of the prostate: A literature review with case report. Indian J Urol 28: 322-324, 2012.
  11. Stearns G, Cheng JS, Shapiro O and Nsouli I: Basal cell carcinoma of the prostate: A case report. Urology 79: e79-e80, 2012.
  12. Chang K, Dai B, Kong Y, Qu Y, Wu J, Ye D, Yao X, Zhang S,Zhang H, Zhu Y, et al: Basal cell carcinoma of the prostate: Clinicopathologic analysis of three cases and a review of the literature. World J Surg Oncol 11: 193, 2013.
  13. Tsuruta K, Funahashi Y and Kato M: Basal cell carcinoma arising in the prostate. Int J Urol 21: 1072-1073, 2014.
  14. Segawa N, Tsuji M, Nishida T, Takahara K, Azuma H and Katsuoka Y: Basal cell carcinoma of the prostate: Report of a case and review of the published reports. Int J Urol 15: 557-559, 2008.
  15. Bassily NH, Vallorosi CJ, Akdas G, Montie JE and Rubin MA: Coordinate expression of cytokeratins 7 and 20 in prostate adenocarcinoma and bladder urothelial carcinoma. Am J Clin Pathol 113: 383-388, 2000.
  16. Simper NB, Jones CL, MacLennan GT, Montironi R,Williamson SR, Osunkoya AO, Wang M, Zhang S, Grignon DJ, Eble JN, et al: Basal cell carcinoma of the prostate is an aggressive tumor with frequent loss of PTEN expression and overexpression of EGFR. Hum Pathol 46: 805-812, 2015.
  17. Montironi R, Epstein JI, Iczkowski KA. Basal cell carcinoma. WHO Classification of the urinary system and male genital organs. 4th Edition; Lyon, 2016; Page 171.

Contributed by Swati Satturwar MD, Rajiv Dhir MD, MBA




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