[Micronodular Thymoma with Lymphoid Stroma;Report of a Case].

We report a surgical case of micronodular thymoma with lymphoid stroma (MNT), which is a rare type of thymoma. A 66-year-old man was referred to our hospital for further examination and treatment of a nodule in the mediastinum. Computed tomography(CT) showed a 20-mm nodule in the anterior mediastinum, and positron emission tomography-CT showed slight uptake in the same region. Thymoma was suspected and videoassisted thymectomy was performed. Histopathological findings showed spindleshaped tumor cells forming storiform, with the background of lymphoid stroma, and the tumor was diagnosed as MNT. The long-term outcome after resection of MNT currently remains unclear, and accumulation of further cases is required.