Basal Cell Carcinoma of Prostate With MSMB–NCOA4 Fusion and a Probable Basal Cell Carcinoma In Situ: Case Report

Basal cell carcinomas of prostate (BCCP) are very rare. Most arise in the transition zone and thus are associated with lower urinary tract symptoms and rarely associated with elevated prostate-specific antigen (PSA). These features make diagnosis/early diagnosis difficult because of the routine protocols followed. Basal cell carcinomas have distinctive histopathological, immunohistochemical, and to some extent also different molecular characteristics. Basal cell carcinoma in situ (BCCIS) is a nonexistent histological lesion as per the current literature, but here is an attempt to describe it through this case. A 74-year-old man presented with hematuria and previous diagnosis of prostatic hyperplasia. Based on this history, he underwent a prostatectomy ad modum Freyer. Pathological examination surprisingly revealed a diffusely infiltrative tumor with nonacinar adenocarcinoma morphology and many glandular structures probably representing BCCIS. Tumor was diagnosed as BCCP. Patient presented with metastasis to the abdominal wall 8 months postprostatectomy. BCCP is an aggressive type of prostate cancer, which might be challenging to diagnose based on routine protocols. This results in delayed diagnosis and treatment and thus poor prognosis. Furthermore, patients with this subtype of prostate cancer need appropriately designed, and maybe a totally different follow-up regimen as PSA is of no use for BCCP patients. Finally, diagnosis of BCCIS, if agreed upon its existence needs to be studied in larger cohorts as a precursor lesion.