Clear cell tumor of the lung: surgical and immunohistochemical findings.

We encountered a clear cell tumor of the lung (CCTL) that was located peripherally, adjacent to the visceral pleura. The tumor could be directly observed during surgery. We believe that this case report describing the surgical and related pathological findings is highly informative. A chest radiograph during routine examination of an asymptomatic 65-year-old woman being treated for hypertension and hyperlipidemia revealed a nodular shadow in the left lung field. Wedge resection was performed by video-assisted thoracic surgery. The in vivo color of the tumor was red, suddenly changing to white after the tumor was clamped. Pathology examination showed a uniform pattern consisting of large clear cells without cytologic atypia or increased mitotic activity. Immunohistochemistry revealed tumor cells positive for vimentin and melanocytic markers (HMB-45 and melan-A) and negative for epithelial membrane antigen and cytokeratin. With the absence of clinical findings in both kidneys, the tumor was diagnosed as a benign CCTL.