2019 Volume 33 Issue 2 Pages 156-160
Among anterior mediastinal tumors, reports of multiloculated tumors are relatively limited, and a multilocular thymic cyst is one of the rare diseases.
In this report, a multilocular thymic cyst is presented, which required differentiation from malignant lymphoma.
The patient was a 40-year-old man, with a BMI of 44.1%. Multiple anterior mediastinal tumors were confirmed by chest CT during follow-up for a left adrenal tumor, sleep apnea syndrome, and bronchial asthma. All of the tumor markers and autoantibodies were negative, FDG-PET/CT showed low accumulation (3 to 4) of SUVmax in the tumor, and T2-weighted chest MRI revealed a multilocular tumor with fluid inside. The tumor was huge, and malignant lymphoma was also suspected. Owing to marked obesity, the patient could not undergo resection of the tumor under single-lung ventilation. So, a surgical biopsy was performed with a 5-cm skin incision in a supine position under two-lung ventilation. The tumor was diagnosed as thymic cysts by rapid pathologic examination. In the resected materials, the cyst walls were thymic tissue, and hyperplasia of lymph follicles was also diagnosed. The surface layer was covered with squamous epithelium. Pathologically, there were cholesteric crystals, atypical giant cells, granulation tissue, hyalinization of the cystic walls, and infiltration of lymphocytes and plasma cells. Currently, the patient shows neither malignancy nor autoimmune diseases. The postoperative course has been uneventful.
