Abstract
BACKGROUND: Cholesterol granuloma in the mediastinum is rarely observed, accounting for 1% of all mediastinum tumors. There have been only a few reports of multifocal cholesterol granulomas of the thymus. We herein report a rare case of multifocal cholesterol granuloma in the thymus that was incidentally detected during follow-up of an aortic aneurysm. CASE PRESENTATION: The patient was a 70-year-old man with dyslipidemia and hypertension who was referred to our hospital to undergo an operation for chest aortic aneurysm. Preoperative computed tomography (CT) showed 4 lesions in the anterior mediastinum measuring up to 4 cm in size with slight contrast enhancement and spotty calcification. Therefore, a thymoma, bronchogenic cyst, or lymphangioma were considered as the preoperative diagnosis. The patient underwent total thymectomy under thoracotomy followed by aortic arch replacement for the aortic aneurysm. The pathological diagnosis was multifocal cholesterol granulomas in the thymus. CONCLUSIONS: Cholesterol granulomas should be included in the differential diagnosis of cystic tumor in the mediastinum, especially in patients with basal disease such as dyslipidemia and hypertension, which may lead to aortic aneurysm. Furthermore, complete surgical resection and a detailed histological evaluation are important for the accurate diagnosis and treatment.