[Hourglass Transmural Lipoma;Report of a Case]

This case report describes a 73-year-old male with an hourglass-type transmural lipoma who was referred because of an abnormal chest shadow. Computed tomography showed a well-defined fatty mass within the intra-and extra-thorax at the right 3rd intercostal portion. Magnetic resonance imaging showed a high-intensity mass that had the same signal level as fat tissue. Therefore, the tumor was diagnosed as an hourglass transmural lipoma. Tumor resection was performed with video-assisted thoracic surgery, and 3rd intercostal muscle tissue approximately 1cm from the tumor border was also resected. The tumor was 6.5×4.5×3.0 cm in size, and histologically diagnosed as an intramuscular lipoma-infiltrating type, without malignancy. Since infiltrating types of intramuscular lipoma often cause recurrence without malignant appearance, tumor specimens require careful examination. Thoracoscopic surgery was useful to determine the excision line from the intra-thorax, for complete resection of the hourglass tumor.