Thymoma of the middle mediastinum: 11C-acetate positron emission tomography imaging.

Thymomas arising outside the anterior mediastinum are very rare. Their occurrence is likely to be related to ectopic thymus tissue. We report a case of thymoma in the middle mediastinum, right paratracheal region. There have been few reports of middle mediastinal thymoma. In the present case, (11)C-acetate positron emission tomography (PET) was useful for a preoperative suggestive diagnosis. Recently, (11)C-acetate has been reported to be a more sensitive PET tracer than (18)F-fluorodeoxyglucose and may be a promising tracer for complementing the deficiency of (18)F-fluorodeoxyglucose in PET imaging.