[A case of multifocal micronodular pneumocyte hyperplasia without clinical findings of tuberous sclerosis].

A 30-year-old woman was referred because of multiple ground-glass opacities (GGOs) on chest CT examination. Lung biopsy was performed. Histologically, multifocal well-demarcated nodular lesions comprising proliferation of type II pneumocytes with mild fibrous thickening of the alveolar septa were observed in the lung tissue. We made a histopathologic diagnosis of multifocal micronodular pneumocyte hyperplasia (MMPH). Neither the clinical findings nor the family history of the patient suggested tuberous sclerosis (TSC). MMPH is a pulmonary manifestation of tuberous sclerosis, together with lymphangioleiomyomatosis (LAM). MMPH should be considered as a differential diagnosis of multiple GGOs in the lung even when findings of TSC and LAM are not recognized.