Tuberous Sclerosis Complex Gene Abnormalities in 2 Patients with Lymphangioleiomyomatosis and Lung Cancer

Background. Lymphangioleiomyomatosis (LAM) is associated with abnormalities of the tuberous sclerosis complex (TSC) tumor suppressor gene, which is characterized by lymph vessel neogenesis. Futhermore, LAM concomitant with lung cancer is rare. Cases. Case 1: A tumor shadow was detected in the right upper lung field of a 64-year-old woman, with multiple cysts in bilateral lungs. Resected lung specimen tests indicated lung cancer (adenocarcinoma) in the right S1 to S3 areas and secondary regional lymph node metastasis. Furthermore, multiple cystic lesions were considered to be LAM. In addition, multifocal micronodular pneumocyte hyperplasia (MMPH) was suspected. Gene analysis confirmed the presence of TSC1 gene abnormalities in the LAM and MMPH lesion sites. Case 2: Pulmonary tumor shadows were detected in the left S3 and S6 areas in a 73-year-old woman, with multiple cysts in bilateral lungs. Resected lung specimen tests indicated double lung cancer (both adenocarcinoma) and secondary regional lymph node metastasis. Furthermore, the multiple cystic lesions were considered to be LAM. Gene analysis showed TSC2 gene abnormalities in 1 lung cancer and the LAM lesion sites. However, their respective gene patterns differed. Conclusion. We report 2 rare cases in which lung cancer and LAM simultaneously occurred. However, the possibility of the involvement of TSC gene abnormalities in the pathogenesis of lung cancer was considered to be low.