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Vol.59 No.5 contents | Japanese/English |
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- Case Report -
A Case of Sclerosing Thymoma with Myasthenia Gravis
Hayato Mine1, Naoyuki Okabe1, Hironori Takagi1, Satoshi Fukai1, Yoshiko Yamaguchi2, Hiroyuki Suzuki11Department of Chest Surgery, Fukushima Medical University, Japan, 2Department of Pathological Diagnosis, Takeda General Hospital, Japan
Background. Thymomas are the most frequent mediastinal tumors, accounting for about 20% of all cases. Sclerosing thymoma, which was first reported by Kuo in 1994, is a relatively rare subtype. Case. A 67-year-old man was diagnosed with myasthenia gravis. He received steroid pulse therapy and intravenous immunoglobulin. Because thoracic computed tomography (CT) showed a 38-mm soft tissue lesion in the anterior mediastinum, we suspected thymoma and performed extended thymectomy. Microscopically, the specimen was characterized by extensive areas of sclerotic fibrocollagen. The pathological diagnosis was sclerosing thymoma, type B1, Masaoka stage I, pT1N0M0, stage I. Conclusions. We concluded that there are certain features characteristic of sclerosing thymoma as a subtype of thymoma by consulting previous reports. Compared with the features of general thymomas, however, we found no distinct differences in terms of the clinical background, such as the gender, age, symptoms, or size of tumors. We also found a slightly higher tendency (35.3%) for merger rate of myasthenia gravis against sclerosing thymoma. In addition, no marked difference in the histology of sclerosing thymoma was found depending on the presence of myasthenia gravis, including in previously reported cases. In the present case, steroid pulse therapy and high-dose intravenous immunoglobulin were administered before surgery, and it has been reported that preoperative treatment affects the histology of thymoma, with strongly convoluted hyalinized fibrosis being a characteristic of sclerosing thymoma. The further accumulation of data and consideration of findings is needed in order to understand the definite clinical features.
key words: Sclerosing thymoma, Anterior mediastinum tumor, Masaoka classification, WHO classification, Myasthenia gravis
Received: January 21, 2019
Accepted: June 14, 2019
JJLC 59 (5): 467-470, 2019
