Squamous cell carcinoma arising from keratinizing desquamative squamous metaplasia of renal pelvis and double paraneoplastic syndrome: Association of two rare entities.

Keratinizing desquamative squamous metaplasia (KDSM) of the upper urinary tract is a rare entity. The present case is of a 45-year-old female patient with an 8-month history of abdominal lump, recurrent right lumbar pain, intermittent fever, and oliguria. Computed tomography kidney, ureter, and bladder revealed a grossly enlarged right kidney along with heterogeneously enhancing soft tissue density mass and internal septations. A differential diagnosis of renal cell carcinoma, urothelial carcinoma, tuberculosis, and pyonephrosis of the kidney was considered as per the clinical and radiological presentation. Intraoperatively, thick fluid was seen in the kidney and its pedicle was seen adhered to duodenum. Partial nephrectomy was done and on microscopic examination squamous cell carcinoma (SCC) was seen arising in the setting of KDSM. Postoperatively, the patient showed an exponential rise of total leukocyte count (100/153 × 103/μl) and serum calcium levels (10.1/17.2/20.4 mg/dl); eventually started deteriorating and later succumbed to illness. We report this rare association of SCC of the renal pelvis arising in KDSM along with the double paraneoplastic syndrome.