A case of micronodular pneumocyte hyperplasia diagnosed through lung biopsy using thoracoscopy.

We present a case of a 39-year-old woman with sporadic tuberous sclerosis (TSC), whose chest radiograph demonstrated bilateral diffuse nodular shadowing. A transbronchial lung biopsy specimen revealed the possibility of multiple atypical adenomatous hyperplasia (AAH), which had not been reported in TSC. Thoracoscopic lung biopsy was, therefore, performed. The specimens revealed the characteristic histological and immunohistochemical features of micronodular pneumocyte hyperplasia, which has been reported as an extremely rare pulmonary manifestation of TSC. In addition, no evidence of AAH or any other pulmonary involvements of TSC including lymphangioleiomyomatosis were detected in biopsy specimens obtained at thoracoscopy.