A rare case report: atypical epithelioid leiomyosarcoma of urinary bladder

Abstract

Background Benign and malignant mesenchymal tumours of the urinary bladder are rare. Non-epithelial tumours account for 1–2% of all primary urinary bladder neoplasms. Among them, leiomyosarcoma is the most common type, representing only 0.1% of bladder cancers. It has three distinct histological variants: the classical spindle cell subtype, the myxoid subtype and the rare epithelioid subtype.1 Case report A 54-year-old female became increasingly symptomatic with urge incontinence and gross haematuria associated with significant weight loss. Abdominal ultrasound showed a large mass in urinary bladder. Core biopsy and then radical cystectomy show sheets of atypical cells which are mostly epithelioid or polygonal in shape. The main differentials include epithelioid leiomyosarcoma, sarcomatoid carcinoma and other sarcomas. Immunostains for smooth muscle markers, calponin, h-caldesmon, SMA, cytokeratin stains, S100 stains, HMB45, c-kit and myoglobin stain were performed. Other immunomarkers of epithelioid tumours were also checked. Overall features are consistent with an epithelioid leiomyosarcoma with urinary bladder involvement. Discussion Epithelioid leiomyosarcoma is a very rare tumour of the urinary bladder. The use of immunohistochemical staining is of value in assisting diagnosis.