Ectopic cervical thymoma accompanied by Good's syndrome.

Ectopic cervical thymoma (ECT) is a rare tumor that is frequently misdiagnosed as a thyroid tumor or other malignancy. A 34-year-old male with a right palpable neck mass had been mistakenly diagnosed with T-cell lymphoblastic lymphoma even after an open biopsy. The atypical clinical course, including hypogammaglobulinemia, led us to the correct diagnosis; ECT accompanied by Good's syndrome (GS). After the intravenous infusion of gammaglobulin, tumor resection and a subsequent video-assisted thoracoscopic extended thymectomy were performed. The final diagnosis was type AB thymoma, Masaoka stage I. This report is, to the best of our knowledge, the first description of this extremely rare combination.