Unusual cystic hamartomatous lung lesion with clinical manifestation of subpleural bullae in a woman of reproductive age: A case report.

Pulmonary hamartoma is a common benign lung disorder, and most cases show solid nodules. Here, we documented the clinicopathological features of a growing, bulla-like, multilocular hamartomatous lung lesion in a woman of reproductive age. To the best of our knowledge, this disorder has not been reported in the literature to date. An asymptomatic 29-year-old Japanese woman with no significant past medical history was referred to our institution for surgical treatment of a bullous lesion in the right upper lobe because the pulmonary lesion had enlarged to multilocular cysts, including a giant bulla, within 1 year, leading to compression of the right lung. The bullous lesion, which was projected from the apex of the lung via a narrow stalk, showed nonemphysematous, multiloculated tissue. The wall mimicked a bronchiolar structure with ciliated, nonatypical epithelium and layers of nonatypical spindle cells that were positive for smooth muscle markers and sex steroid hormone receptors. No cartilage was included in the lesion. We believe that this may be a novel form of hamartoma. This disorder may be included in a differential diagnosis of subpleural bullous diseases in women of reproductive age.