Encountering A Rare Entity: A Case Report of Prostatic Sarcomatoid Adenocarcinoma.

Sarcomatoid carcinoma of the prostate is a rare and aggressive malignancy characterized by biphasic differentiation with epithelial and mesenchymal components. Diagnosing this entity is challenging due to its overlapping histological features with other prostatic neoplasms. We report a case of an elderly patient who presented with acute urinary retention and a history of lower urinary tract symptoms, including difficulty in micturition and poor urinary stream. A transrectal ultrasound-guided biopsy was performed for an ill-defined lesion in the right lobe of the prostate with an elevated PSA level of 30 ng/mL. A bone scan revealed metastatic lesions. Histopathological examination confirmed sarcomatoid carcinoma with a Gleason score of 8 (Grade Group 4). The tumor exhibited a biphasic morphology, with malignant spindle cells interspersed with a high-grade carcinoma component. Immunohistochemistry demonstrated vimentin, smooth muscle actin (SMA), and SATB2 positivity in the sarcomatoid component, while the carcinomatous component showed positivity for pan-cytokeratin (pan-CK), CK7, and CK20. PSA was negative in both components. This case highlights the aggressive nature of sarcomatoid carcinoma and highlights the essential role of histopathology and immunohistochemistry in its accurate diagnosis and differentiation from other spindle cell tumors.