Renal carcinoma with (6;11)(p21;q12) translocation: report of an adult case.

An extremely rare adult example of renal carcinoma with t(6;11)(p21;q12 or q13) is presented here. The tumor of a 45-year-old Japanese male, excised under the diagnosis of renal cell carcinoma, was a well circumscribed 7 cm mass with light brown sectioned surfaces. Histologically, it was composed of a major population of large polygonal epithelioid cells in a nested alveolar growth and a subpopulation of smaller cells clustering around hyaline basement membrane material. The former cells possessed ample, clear to eosinophilic granular cytoplasm with well-defined cell borders and the latter was frequently accompanied by psammomatous calcification. These tumor cells exhibited immunoreactivity for melanoma markers, transcription factor EB and cathepsin K, but were not reactive for epithelial markers and transcription factor E3. While pulmonary metastatic foci that were noted preoperatively progressed rapidly following interferon-based therapy, subsequent sunitinib malate yielded a partial response and stabilized the lung metastasis for 6 months after surgery. We could trace 20 cases of 6p21 translocation renal carcinoma, among which only four were in individuals older than 40 years. Description of a new case like this is important since little is known about the prognosis and treatment of adult patients with this condition.