Cytologic features of renal medullary carcinoma: A study of three cases

BACKGROUND. Renal medullary carcinoma is a rare tumor that is most common in young black men with sickle cell disease or trait. Patients often present with advanced disease at the time of diagnosis, and their prognosis is poor, even with aggressive therapy. The clinical and pathologic features of renal medullary carcinoma have been described in several articles, but reports describing the cytologic features are rare. METHODS. In the current report, the authors describe the cytologic features of three cases of renal medullary carcinoma. The patients were young black men with sickle cell trait ages 20 years, 33 years, and 33 years. RESULTS. All three patients presented with hematuria, flank pain, and a renal mass. The cytologic specimens from all three patients showed primarily cohesive groups of cells with vacuolated cytoplasm that often displaced or indented the nuclei. The nuclei often had irregular membranes, coarse or vesicular chromatin, and prominent nucleoli. Both of the two patients who were tested with fluorescence in situ hybridization were negative for the bcr/abl rearrangement. CONCLUSIONS. Renal medullary carcinoma should be considered in the differential diagnosis of patients who present with hematuria or a renal mass, especially in young black men with sickle cell disease or trait. Cytologically, renal medullary carcinoma cells appear similar to the cells in high-grade carcinoma. Immunohistochemical studies can be helpful in distinguishing renal medullary carcinoma from other poorly differentiated kidney tumors, except for collecting duct carcinoma. The clinical findings are key to diagnosing renal medullary carcinoma.