BACKGROUND Chromophobe renal cell carcinoma is a rare subtype of renal cell carcinoma which accounts for 4% to 6% of renal cell carcinoma subtypes. These tumors generally have a good prognosis. Typical radiological features include a well-defined homogeneous mass and a hypo-vascular soft tissue enhancement. Cystic chromophobe renal cell carcinoma is a very rare entity in which the overall estimated cystic renal cell carcinoma of all subtypes account for 4%. We describe a rare presentation of chromophobe renal cell carcinoma presenting as a unilocular cystic mass with mural nodules. CASE REPORT A 28-year-old healthy male presented with a history of right upper quadrant fullness and discomfort. Hepatomegaly was expected on examination. Ultrasonographic assessment revealed a normal liver size and echo texture. However, a large cystic mass measuring 15.7×12.8 cm was found arising from the right kidney which showed no internal vascularity but turbid fluid and debris within the dependent regions of the mass. Multiphase computed tomography scan showed a large unilocular cystic mass with enhancing mural nodules. There was no lymphovascular or peri-renal invasion. The patient underwent uneventful total right renal nephrectomy. Histological examination revealed a chromophobe renal cell carcinoma of grade II. CONCLUSIONS Cystic renal neoplasm differential diagnosis varies from benign entities to malignant neoplasms. Knowledge of the variable common features for each renal cell carcinoma subtypes can aid in narrowing the differential diagnosis and prompt appropriate surgical management since a possibility of nephron sparing technique might still take place in suspected cystic chromophobe renal cell carcinoma but never for cystic clear cell renal cell carcinoma.

The American journal of case reports. 2019 May 01*** epublish ***

Maram H AlGhamdi, Nayef A AlShabyli, Abdullah Alayed

Department of Radiology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.