SARCOMATOID UROTHELIAL CARCINOMA OF BLADDER - A RARE HISTOLOGICAL VARIANT

Introduction: Urothelial carcinoma (UC) is the most common histological type of bladder cancer. Around 75% of bladder cancers are classified as pure UC, and 25% are urothelial and nonurothelial histological variants. Sarcomatoid UC is a rare variant, accounts for 0.1%–0.3% of all urothelial carcinomas of bladder. It is a biphasic malignant neoplasm with morphologic and immunohistochemical evidence of both epithelial and mesenchymal differentiation. Objective: To study the histomorphological and immunohistochemical features of sarcomatoid urothelial carcinoma. Methods: We received TURBT (Trans Urethral Resection of Bladder Tumor) specimen for histopathological evaluation in the department of pathology, DY Patil medical college, Kolhapur. Routine tissue processing of bits was done and H & E stained sections were subjected for detailed microscopic evaluation and various immunohistochemical markers were applied on the paraffin embedded tissue blocks. Results: A95years old female patient presented with hematuria and anemia.On cystoscopy polypoidal lesion seen in the lateral wall of urinary bladder.No history of previous surgery on urinary bladder.TURBT done. On gross, there were multiple, irregular, grey white strips of tissue altogether weighing 160gms. On microscopy, neoplasm with papillary architecture was seen invading lamina propria. Chondromyxoid, rhabdoid and malignant fibrohistiocytic tumor like areas noted. Immunohistochemical workup revealed positive staining with cytokeratin, vimentin and GATA3 and negative with H-Caldesmon, SMA and Myogenin. Conclusion: Sarcomatoid UC is seen in elderly. Morphologically, the lesion mimics sarcoma, immunohistochemistry workup aids in definitive diagnosis, as it has poor prognosis compared to pure UC.