PITUITARY ADENOMA
62-year old man with history of subungual melanoma history left index hand finger surgery in July 2001 with left axillary sentinel node positive and negative lymphadenectomy. Non-Hodgkin lymphoma of the scalp, neck and lung stage IV diagnosed in April 2004. He received 4 cycles of chemotherapy (CHOP followed by Mabthera). Follow up biopsy : NHL large cell B immunophenotype, CD30 negative. Gallium 67 scintigraphy : within normal limits. CT abdomen: nodular right lung base of just over 1 cm, two nodular lesions approximately 1.5 cm in the left perirenal space, possible metastatic lesions, hypodense left renal cortical nonspecific 1 cm. Brain CT: normal. Afterwards MRI shows what would be a pituitary adenoma. PET-FDG shows increased uptake suggestive of pituitary adenoma (arrows). The rest of the study was normal. Unfortunately, patient died 3 years later from metastatic melanoma.
Hyun et al. found 0.8% of incidental pituitary uptake with macroadenomas, microadenomas and malignancy. Incidental pituitary uptake is an unusual finding, SUV over 4 warrant further diagnostic evaluation (1).
References:
1 Hyun SH,
Choi JY, Lee KH, Choe YS, Kim BT. Incidental focal 18F-FDG uptake in the
pituitary gland: clinical significance and differential diagnostic criteria. J
Nucl Med. 2011 Apr;52(4):547-50.