BACKGROUND/AIMS: Although magnetic resonance imaging (MRI) is a good visual modality for the evaluation of pituitary lesions, it has limited value in the diagnosis of mixed nodules and some cystic lesions. We evaluated the usefulness of 18F-fluorodeoxyglucose positron emission tomography (FDG PET) for patients with pituitary lesions. METHODS: 18F-FDG PET and MRI were performed simultaneously in 32 consecutive patients with pituitary lesions. The relationships between FDG uptake patterns in PET and MRI findings were analyzed. RESULTS: Of 24 patients with piuitary adenomas, 19 (79.2%) showed increased uptake of 18F-FDG in the pituitary gland on PET scans. All patients with pituitary macroadenomas showed increased 18F-FDG uptake on PET scans. Meanwhile, only five (50%) of the 10 patients with pituitary microadenomas showed positive PET scans. Interestingly, of two patients with no abnormal MRI findings, one showed increased 18F-FDG uptake on PET. For positive 18F-FDG uptake, maximum standardized uptake values (SUVmax) > 2.4 had 94.7% sensitivity and 100% specificity. In addition, SUVmax increased in proportion to the size of pituitary adenomas. Most cystic lesions did not show 18F-FDG uptake on PET scans. CONCLUSIONS: About 80% of pituitary adenomas showed positivity on PET scans, and SUVmax was related to the size of the adenomas. PET may be used as an ancillary tool for detection and differentiation of pituitary lesions.
Adenoma/pathology/*radionuclide imaging ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Female ; Fluorodeoxyglucose F18/*diagnostic use ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Pituitary Gland/pathology/*radionuclide imaging ; Pituitary Neoplasms/pathology/*radionuclide imaging ; *Positron-Emission Tomography ; Predictive Value of Tests ; Radiopharmaceuticals/*diagnostic use ; Tumor Burden ; Young Adult

Zollinger-Ellison syndrome (ZES) is characterized by gastrinoma and resultant hypergastrinemia, which leads to recurrent peptic ulcers. Because gastrinoma is the most common pancreatic endocrine tumor seen in multiple endocrine neoplasia type I (MEN 1), the possibility of gastrinoma should be investigated carefully when patients exhibit symptoms associated with hormonal changes. Ureteral stones associated with hyperparathyroidism in the early course of MEN 1 are known to be its most common clinical manifestation; appropriate evaluation and close follow-up of patients with hypercalcemic urolithiasis can lead to an early diagnosis of gastrinoma. We report a patient with ZES associated with MEN 1, and urolithiasis as the presenting entity. A 51-year-old man visited the emergency department with recurrent epigastric pain. He had a history of calcium urinary stone 3 years ago, and 2 years later he had 2 operations for multiple jejunal ulcer perforations; these surgeries were 9 months apart. He was taking intermittent courses of antiulcer medication. Multiple peripancreatic nodular masses, a hepatic metastasis, parathyroid hyperplasia, and a pituitary microadenoma were confirmed by multimodal imaging studies. We diagnosed ZES with MEN 1 and performed sequential surgical excision of the gastrinomas and the parathyroid adenoma. The patient received octreotide injection therapy and close follow-up.
Gastrinoma/metabolism/pathology/ultrasonography ; Gastrins/metabolism ; Humans ; Immunohistochemistry ; Liver/radiography ; Magnetic Resonance Imaging ; Male ; Mesenteric Artery, Superior/radiography ; Middle Aged ; Multimodal Imaging ; Multiple Endocrine Neoplasia Type 1/complications/*diagnosis/radiography ; Pancreas/radiography/radionuclide imaging ; Pituitary Gland/radiography ; Positron-Emission Tomography ; Radiopharmaceuticals/diagnostic use ; Thyroid Gland/ultrasonography ; Tomography, X-Ray Computed ; Urolithiasis/*diagnosis/etiology ; Zollinger-Ellison Syndrome/complications/*diagnosis