[Successful thoracoscopic surgery for mediastinal parathyroid tumor with preoperative intravenous methylene blue infusion; report of a case].

A 56-year-old woman was referred to our hospital presenting high serum levels of calcium (Ca) and intact-parathyroid hormone (PTH) and an anterior mediastinal nodule of 18×13 mm in size on chest computed tomography (CT). Tumor was suspected of a parathyroid tumor. 99mTc-methoxy-isobutylisonitrile( MIBI) scintigram showed abnormal radioactive tracer accumulation in the lesion. 3 ml/kg of methylene blue was administered intravenously an hour before surgery, and the stained tumor was successfully resected by thoracoscopic surgery. Pathological diagnosis was parathyroid hyperplasia. Postoperative course was uneventful and serum levels of Ca and intact-PTH returned to normal ranges.