Localization of mediastinal parathyroid adenoma by Tl-201 scintiscan and SPECT

Summary A 64-year-old female patient was admitted to our department for fatigue, pain in the right upper abdomen, obstipation, and meteorism. The laboratory findings showed total calcium and ionized calcium elevated, phosphate close to lower limit, and parathyroid hormone increased. Tl-201/Tc-99m subtraction scintiscan of the neck and upper mediastinal region did not give any evidence of isolated enhanced uptake suggesting the presence of parathyroid adenoma. After further increases in calcium and parathyroid hormone level Tl-201 whole-body scan and single photon emission computed tomography of the thoracic region were performed. These revealed a circumscribed Tl-201 uptake in the mediastinum immediately cranial ventral to the heart base. The postcontrast transmission computed tomography of this area confirmed the finding of the Tl-201 scintigraphy with a 4×3×2 cm tumor. After sternotomy and surgical removal of the mediastinal parathyroid adenoma (chief cell adenoma), calcium and parathyroid hormone levels returned to normal values.Abbreviations Ca total calcium - Ca²⁺ ionized calcium - DSA digital subtraction angiography - hPTH human parathormone - MBq mega-Becquerel - mg milligram - MRI magnetic resonance imaging - mval millival - Ph phosphate - pmol picomol - RIA radioimmunoassay - SPECT single photon emission computed tomography - Tc-99m technetium 99m - TCT transmission computed tomography - Tl-201 thallium 201