Squamous cell carcinoma of the renal pelvis associated with kidney stones: a case report.

A 70-year-old female with a long-standing history of kidney calculi presented with vague abdominal pain. Work-up included a CT and MRI of the kidneys. A mass was demonstrated in the superior pole of the left kidney. The mass was biopsied percutaneously under CT guidance. Pathology revealed a poorly differentiated carcinoma, but was inconclusive for a definitive cell type. The patient subsequently underwent a nephrectomy that revealed squamous cell carcinoma of the renal collecting system. She had an uneventful postoperative recovery. Chronic renal calculi pose a risk for the development of squamous metaplasia that may lead to squamous cell carcinoma. Although this malignancy is rare in the upper urinary tracts, patients with long-standing nephrolithiasis should be monitored. This diagnosis should be included in one's differential when evaluating a renal mass that is associated with chronic inflammatory conditions.