Co-occurrence of giant cell carcinoma and adenocarcinoma of the lung accompanied by multifocal micronodular pneumocyte hyperplasia associated with tuberous sclerosis

Multifocal micronodular pneumocyte hyperplasia (MMPH) is a rare pulmonary manifestation of tuberous sclerosis complex (TSC). We report the case of a patient who developed lung giant cell carcinoma and adenocarcinoma accompanied by MMPH associated with TSC. Although she received chemotherapy postoperatively, she died of relapse of the pulmonary giant cell carcinoma 7 months after diagnosis of the lung carcinomas. This case indicates the possibility that MMPH, like atypical adenomatous hyperplasia, can occur as a preneoplastic lesion of lung adenocarcinoma and that a TSC gene mutation might be involved in the pathogenesis. In addition, co-occurrence of these two rare diseases, MMPH and giant cell carcinoma, may facilitate understanding of the pathogenesis of giant cell carcinoma, and suggests involvement of a TSC gene mutation.