2016 Volume 30 Issue 1 Pages 92-95
The patient, a woman in her 30s, exhibited gestational hypertension and hypercalcemia in her 33rd gestational week. She underwent detailed testing after giving birth in her 34th gestational week. High serum calcium and intact parathyroid hormone levels were observed, and a computed tomography scan showed a 13-mm mass in the anterior mediastinum. Tc-99 m methoxyisobutylisonitrile scintigraphy revealed an uptake consistent with the mass in the anterior mediastinum. The patient was diagnosed with ectopic parathyroid adenoma, and thoracoscopic surgery was performed. Immediately prior to surgery, methylene blue was administered in an intravenous drip and monitoring was conducted using near infrared spectroscopy. After administering methylene blue, oxygen saturation decreased to within the 80% range; however, there was no change in the regional saturation of oxygen. A blue-stained tumor was noted in the thymus and extracted. Histologically, no malignant findings were noted in the ectopic parathyroid adenoma. When administering methylene blue, we observed pseudohypoxemia, wherein a pulse oximeter showed decreased oxygen saturation despite a normal arterial oxygen pressure. In this case, surgery was performed safely using near infrared spectroscopy.
