High-Grade Urothelial Carcinoma of Bladder Transforming to Micropapillary Variant on Follow-Up.

Micropapillary variant of urothelial carcinoma (UC) of the bladder is an aggressive tumour, comprising 0.6-6% of all UC. It generally presents with high-grade and stage, and has been reported as having a worse prognosis when compared to traditional UC. We report the case of a 58-year-old man who presented with macroscopic haematuria. The patient was diagnosed with high-grade urothelial carcinoma and returned with recurrence after 16 months. Histopathology after transurethral biopsy revealed a non-muscle invasive high-grade bladder tumour at first presentation, whereas tumour recurrence was reported after 1.5years. The histopathology at recurrence revealed a high-grade, muscle invasive, micropapillary variant of urothelial carcinoma with focal adenomatous morphology. Immunohistochemical expression of CK7/CK20 in tumour cells and negativity for PSA, AMACR, and CDX2 in paraffin section helped in identifying the tumour as primary in the urinary bladder. Radical cystectomy was performed and the patient has no distant metastases on follow-up. The specific morphology even within the high-grade urothelial cancer cases is important to discern for proper treatment.