FDG-PET/CT in the detection of pituitary stalk ACTH-secreting adenoma

Excerpt

A 50-year-old male diagnosed with an adrenocorticotropic hormone (ACTH)–dependent Cushing syndrome, and inferior petrosal sinus sampling displayed an ACTH concentration 4 times higher than that of peripheral blood. MRI demonstrated abnormal signal at posterior pituitary as well as thickening at pituitary stalk. The patient underwent transnasal endoscopic pituitary lesion resection, but immunohistochemistry demonstrated negative ACTH, and no significant clinical improvement was observed. The patient was admitted to our hospital and whole-body FDG-PET/CT was performed. Cranial FDG-PET/CT showed a 0.5 × 0.5-cm lesion at pituitary stalk with radioactivity (SUVmax 3.2, arrow noted), and no abnormal FDG uptake was found in the chest cavity or other part of the body. The patient was considered having a pituitary stalk ACTH-secreting adenoma, and a craniotomy for pituitary stalk lesion was performed. Pathology confirmed ACTH-secreting adenoma (ACTH-positive for immunohistochemistry), and patient displayed significant clinical improvement. …