Radiation-induced sarcomatoid malignancy of the prostate – A case report

Abstract

Sarcomatoid carcinoma of the prostate accounts for less than 0.1% of all prostatic malignancies. We present the case of a highly-aggressive radiation-induced sarcomatoid malignancy in a 76-year-old man with a significant past history of low-grade prostate adenocarcinoma treated with radiotherapy six years prior. Imaging performed to investigate perianal pain revealed a 160 mm polypoidal mass involving the bladder, prostate and urethra. Microscopic analysis of the transurethral tumour resection specimen revealed a malignant spindle cell tumour with high mitotic activity, cytological atypia, and extensive necrosis. A month later, the patient proceeded to a pelvic exenteration, examination of which showed involvement of bladder, prostate, penis and anus by tumour. Three weeks following this operation, the patient represented with bowel obstruction and urosepsis. Repeat imaging showed a large recurrent tumour mass extending into the anterior abdominal wall and involving small bowel. The patient was palliated and succumbed shortly thereafter. Despite extensive sampling of both transurethral resection and pelvic exenteration specimens, no definite tumour epithelial component was identified morphologically or immunohistochemically. Nevertheless, a diagnosis of sarcomatoid carcinoma was favoured over undifferentiated sarcoma based on the clinical history and visceral tumour location. Clinicopathological features of this case and the relevant research literature will be discussed.