Long-term follow-up after surgical removal of thymolipoma

The thymus is the largest lymphoid tissue of the human body, located in the superior mediastinum, growing until puberty and then involuting to nearly disappear around 18 years [1]. It can be affected by benign and malignant neoplasms. Thymolipoma, comprising 2–9% of thymic neoplasms, is a rare benign neoplasm of the thymus composed of mature adipose and thymic tissue [1]. Less than 200 cases had been reported in the literature by 2015 [2]. Although rare, it should be considered in the differential diagnosis for any anterior mediastinal mass with fat density.
A 22-year-old man was admitted to Ghaem teaching hospital, Mashhad, Iran with 3 months history of dyspnea on exertion and chest heaviness. He had no other chest, constitutional symptoms or signs of autoimmune disorders. On physical examination the only abnormal finding was complete absence of vesicular breath sounds in the left hemithorax. Posteroanterior chest radiograph revealed a huge fat density obscuring the left heart and mediastinal border (Figure 1).
Chest computed tomography (CT) showed a large mass (22 × 19 × 17 cm) with fat density admixed with soft tissue strands occupying the anterosuperior mediastinum extending to the left hemithorax (Figure 2). Laboratory tests were not remarkable. The patient was scheduled for surgical resection with a primary diagnosis of thymolipoma. Care was taken as regards malacia or external pressure of the left main bronchus. Partial sternotomy was accompanied with left thoracotomy through the fifth left intercostals space. The tumor (31 × 15 × 12 cm) resided left of the pericardium without any invasion to pericardial or lung tissue (Figure 3).Dehiscence of the tumor by blunt and sharp dissection was easily done with care about preservation of the left phrenic nerve.
A large encapsulated tumor with a yellowish elastic surface and soft yellowish fatty tissue by incision was removed (Figure 4). Histopathological examination revealed mature adipose tissue and hyperplastic thymic structures with Hassel’s corpuscles identified as a benign thymolipoma.
The postoperative period was uneventful, and the patient was discharged on the 5th postoperative day with good general condition. Frequent yearly visits until 10 years showed no symptom or sign of recurrence or any clue in favor of autoimmune disorders.
Lange reported the first case of thymolipoma in 1612, but the term of thymolipoma was used many years later by Eid et al. in 2017 [3]....


View full text...