Inverted intercostal hernia of soft tissue manifested as slow-growing chest wall tumor after thoracotomy.

An 80-year-old woman had an asymptomatic chest wall tumor. She had undergone thoracotomy to treat a benign lesion 11 years previously. Chest computed tomography revealed a convex lens-shaped mass 7 cm in diameter in the chest wall. Positron emission tomography demonstrated mild accumulation of F-deoxyglucose. We performed an exploratory thoracotomy; however, no mass lesion was found. Therefore, we thought that the soft tissue of the back was drawn into the pleural cavity through the widened intercostal space during the previous thoracotomy. We simply aligned the ribs using heavy surgical sutures. The patient has experienced good recovery, with no recurrence since the surgery.