Second primary bronchogenic carcinomas after small cell carcinoma. Report of two cases and review of the literature.

Second primary carcinomas of the lung are well described. However, their occurrence following initial diagnosis of small cell lung carcinoma is rare. The development and antemortem diagnosis of metachronous second primary bronchogenic carcinomas in two long-term (more than four years) survivors of small cell lung cancer is described. The histologic types of the second carcinomas were mucoepidermoid and bronchoalveolar. On the basis of a review of the literature, only eight similar cases have been reported; none of the second primaries was mucoepidermoid or bronchoalveolar. The question of whether second primaries after small cell lung cancer represent true metachronous carcinomas, different degrees of differentiation of the same tumor, or the emergence of a previously unrecognized synchronous tumor is discussed. The need for awareness of this complication and the necessity for life-long follow-up in long-term survivors of small cell lung cancer is emphasized.