A RARE METASTATIC SITE OF RENAL CELL CARCINOMA WITH A RARE PATHOLOGY

Renal cell carcinoma (RCC) is a heterogeneous disease with several different histological variants and associated molecular genetic changes.Unclassified RCC is a diagnostic category for those tumours that do not fit into any of the four known common categories of RCC namely, clear-cell, papillary, chromophobe, or collecting duct carcinoma. The frequency of this type of RCC is quite variable, accounting for 0.7 - 5.7 percent of all RCCs . This category is associated with unfavourable histological features and aggressive behavior. RCC has widespread and unpredictable metastatic potential. The most common metastatic sites are the lungs, lymph nodes, bones, liver, and brain.In several autopsy series, about 0.4 percent of cases with RCC had skeletal muscle metastases . we report a rare case of RCC with unclassified histology with metastasis in gluteal region.A 56 years old male presented with right loin mass,loin pain and hematuria for 3 months duration.CT KUB showed an enhancing renal mass replacing whole of right kidney sparing the lower pole.MRI Abdomen and pelvis done to evaluate a soft tissue swelling in the right gluteal region suggestive of metastasis.Cytoreductive nephrectomy with excision of the gluteal mass was done.Final diagnosis came out as unclassified renal cell carcinoma Furhmann grade III and gluteal mass showed secondary carcinomatous deposits.