The role of 18F-FDG PET/CT and single isotope 99mTc-tetrofosmin scintigraphy combined with SPECT in diagnosis of multiple endocrine neoplasia type 1 syndrome.

We present a case of a 47-year-old woman with type 1 multiple endocrine neoplasia, primary hyperparathyroidism, insulinoma, and nonfunctioning pituitary adenoma. In July 2017, the patient was referred to the Department of Nuclear Medicine of St George University Hospital in Plovdiv for a PET/CT scan because of persistent hypoglycemic episodes and high serum insulin levels. A whole-body PET/CT examination was performed 65 min after intravenous application of 188 MBq 18F-FDG on a hybrid PET/CT scanner (Biograph mCT 64, Siemens). We detected a low metabolically active lesion 10 mm in diameter (SUVmax - 2.00), located below the left thyroid lobe suspicious for parathyroid adenoma. In the remaining scanned areas there were no PET/CT data for other areas with increased glucose metabolism with malignant characteristics that could be associated with the underlying disease.