Abstract Introduction Thymolipoma is a rare benign tumor of the anterior mediastinum, accounting for approximately 2-9% of all thymic neoplasms. Composed of mature adipose and thymic tissue, it typically exhibits slow growth and is often discovered incidentally. Because of its indolent course, symptoms usually occur only when the mass becomes large enough to compress adjacent cardiopulmonary structures. The nonspecific respiratory manifestations can lead to misdiagnosis as asthma or recurrent pneumonia. We present a case of a 17-year-old male with chronic cough and recurrent respiratory symptoms ultimately diagnosed with a giant thymolipoma. Case Presentation A 17-year-old male was evaluated for an abnormal chest radiograph obtained at an outside facility. His mother reported recurrent episodes of cough, shortness of breath, and fatigue, often diagnosed as pneumonia. He experienced six to seven such episodes over several years, with partial improvement after albuterol inhaler use. He denied fever, chills, or sputum production.On examination, he appeared well, with stable vital signs. Breath sounds were decreased over the left hemithorax, without wheezes or crackles. The remainder of the examination was unremarkable. Pulmonary function testing revealed a mild restrictive defect: FEV1 2.95 L (74% predicted), FVC 3.43 L (74% predicted), and FEV1/FVC 86%. Chest X-ray showed an enlarged cardiac silhouette with elevation of the left hemidiaphragm and left lower-lobe atelectasis. Echocardiography was normal.Chest CT demonstrated a large, fat-containing anterior mediastinal mass with soft-tissue components measuring 9.6 × 15.3 × 17.3 cm, occupying most of the left hemithorax and encasing the cardiac silhouette—features consistent with thymolipoma. The patient underwent left thoracotomy with complete resection. Grossly, the mass measured 27.5 × 17.5 × 7.8 cm and weighed 1.5 kg. Histopathology confirmed thymolipoma. The postoperative course was uneventful, with full resolution of respiratory symptoms. Discussion Fewer than 300 cases of thymolipoma have been reported. The tumor may grow to fill an entire hemithorax and cause lung compression or mediastinal shift. Imaging typically reveals a well-circumscribed, fat-density anterior mediastinal mass that can mimic cardiomegaly, effusion, or liposarcoma. Complete surgical excision is curative, and recurrence or malignant transformation has not been described.This case underscores the importance of considering thymolipoma in adolescents with chronic respiratory symptoms and large mediastinal masses, as timely surgical management is both diagnostic and curative. This abstract is funded by: University Of Missouri Kansas City
Karrar et al. (Fri,) studied this question.