[An hourglass type intrathoracic lipoma--a case report of surgical treatment]

We report a rare case of hourglass type intrathoracic lipoma. Until now, there are 114 reported cases on intrathoracic lipoma in Japanese literature, among which 22 are hourglass type. The patient was a 43-year-old woman, who was found to have a pleural tumor on her chest X-ray examination for healthy check-up. Computed tomography showed that it had intra- and extrathoracic portion with almost the same density as the subcutaneous fat tissue. The tumor was excised along with pleura, periostia and intercostal muscle approximately 1 cm apart from it. It was dumbbell-shaped and weighed 30 grams. Microscopically it was found to be intramuscular lipoma. According to Fletcher, intramuscular lipoma was classified into two groups of infiltrative and non-infiltrative type. In their cases, infiltrative intramuscular lipomas recurred up to 19%, mainly secondary to incorrect resection. Our case corresponds to infiltrative type. We consider that intrathoracic lipoma, though benign, have to be resected radically with utmost care.