The histologic spectrum and significance of clear‐cell change in lung carcinoma

We reviewed 348 consecutive cases of lung carcinoma to determine the incidence and significance of clear‐cell carcinoma. Areas composed of clear cells were common in all types of lung carcinoma except small cell carcinoma. The clear cytoplasm in most cases contained glycogen. We found only one tumor fulfilling the World Health Organization (W.H.O.) criteria for clear‐cell carcinoma. There were 14 other tumors which contained over 50% clear cells and therefore could be considered clear‐cell carcinomas by some published criteria. Ten of these tumors also showed foci of epidermoid differentiation while four showed gland formation. The prognosis of tumors containing even large areas of clear cells does not appear to differ from that reported for the common lung carcinomas. We feel that clear‐cell carcinoma should not be considered a distinct clinicopathologic entity. Rather, tumors composed even predominantly of clear cells should be classified according to the major W.H.O. categories.