Renal cell carcinoma with rhabdoid features: an aggressive neoplasm with overexpression of p53.

CONTEXT: Adult renal cell carcinoma (RCC) with rhabdoid features is a recently recognized morphologic variant of kidney carcinoma. To date, only very few studies have been published on this subject and p53 was not previously studied.

OBJECTIVE: To evaluate clinical attributes, morphology, and immunohistochemistry in RCC with rhabdoid component.

DESIGN: Reviewing a consecutive series of 310 RCCs, we identified 14 cases of RCC with rhabdoid features. All cases were reviewed and subjected to detailed clinical and pathologic studies with immunohistochemical evaluation of p53.

RESULTS: All tumors were clear RCCs with rhabdoid component representing from 5% to 50% of the tumor volume. Rhabdoid cells were large with a central eosinophilic intracytoplasmic inclusion and an eccentric atypical nucleus. Tumor necrosis was common (13/14) and sometimes extensive. Nine of 14 tumors were staged pT3, 4 of 14 were pT2, and only 1 tumor was pT1. On immunohistochemistry, rhabdoid cells were positive for vimentin (14/ 14), epithelial membrane antigen (11/14), and cytokeratin (9/14). Desmin and smooth muscle actin were always negative. p53 was positive in 10 of 14 tumors in the rhabdoid areas (5%-50% of tumor cells stained) but only in 5 of 14 cases in usual clear renal cell areas. In the follow-up, 10 of 14 patients developed metastases and 6 of 14 died of the disease. The median of survival was 8 months.

CONCLUSIONS: We showed that RCC with rhabdoid features is a very aggressive neoplasm with a poor prognosis. We observed an overexpression of p53 in the rhabdoid component that may be implicated in the tumor dedifferentiation.