AbstractA rare case of retroperitoneal transitional cell carcinoma arising from primitive urogenital remnants is described in a 50‐year‐old female. The patient had a 15 × 12 cm firm to cystic mass in the left iliac fossa which was markedly adherent to retroperitoneal structures and which could not be excised. Biopsy from the mass revealed transitional cell papillary carcinoma. Intravenous pyelogram and cystoscopy were normal. Cystogram done postoperatively did not show any communication with any adult organ. Radiotherapy resulted in only partial regression, and the patient died about 2 years l