Thymolipoma: clinicopathologic review of 33 cases

The clinical, radiologic, and pathologic features of 33 cases of mediastinal thymolipoma are presented. The patients' ages ranged from 2 to 64 (mean, 33) years; 18 were male and 15 were female. Clinically, the majority of patients (18 cases) were asymptomatic. Five patients presented with upper respiratory symptoms, two patients presented with chest pain, two patients with myasthenia gravis, and one patient with a neck mass; no clinical information was available in four patients. All the tumors were located in the anterior mediastinum and in all cases complete surgical resection of the mass was accomplished. Radiographically, 20 cases showed an anterior mediastinal tumor; when available, computed tomography and/or magnetic resonance imaging demonstrated a mixture of fat and soft tissue elements in these tumors. Grossly, the tumors were described as fairly well-circumscribed, soft, yellowish, fatty tumors with focal solid areas. The tumors varied in size from 4.5 to 36 cm in greatest dimension. Histologically, they were characterized by the presence of abundant mature adipose tissue admixed with areas containing remnants of thymic tissue. The fatty tissue consisted of mature adipocytes devoid of atypia, and the thymic tissue component varied from strands of atrophic thymic epithelium to large areas containing thymic parenchyma showing the typical mixed epithelial/lymphocytic architecture with numerous Hassall's corpuscles. Areas of calcification and cystic degeneration of Hassall's corpuscles were quite prominent in a large number of cases. Our study shows that thymolipomas span the age ranges from the very young to adult individuals with a slight prevalence for patients under the age of 40.(ABSTRACT TRUNCATED AT 250 WORDS)