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Abstract: A 34-year-old woman who presented with severe psychosis and clinical features of Cushing syndrome underwent 18 F-FDG PET/CT that revealed hypermetabolic lung lesion along with predominantly increased metabolism of bilateral basal ganglia, a scintigraphic correlate of acute psychosis. The lesion was surgically excised and histopathologically proven to be adrenocorticotropic hormone-producing lung carcinoid. Posttreatment 18 F-FDG PET scan showed restoration of normal brain metabolism with complete reversal of psychosis. Even though rare, one should be aware of psychosis as an initial presentation of Cushing syndrome and use of 18 F-FDG PET/CT for mapping brain metabolism as shown in this case., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Paragangliomas (PGLs) due to succinate dehydrogenase subunit B (SDH-B) mutation can be aggressive. A 40-year-old woman with normetanephrine-secreting, extra-adrenal, abdominal PGL due to SDH-B genetic mutation underwent surgical excision of primary, followed by whole-body I-MIBG scan after 6 months, which showed no abnormality. However, Ga-DOTANOC and F-FDG PET/CT scans showed primary site recurrence, hepatic and skeletal metastasis, with latter scan revealing more lesions. We suggest that F-FDG PET should be done in all patients with PGL due to SDH-B mutations, as it may show additional unsuspected lesions that may be missed by other tracers.

A 37-year-old woman with clinical and biochemical features of ectopic adrenocorticotropic hormone (ACTH) syndrome underwent 68Ga DOTANOC PET/CT to localize the source of ectopic ACTH secretion. The images showed 35 × 45-mm retroperitoneal mass with significantly increased tracer uptake. Plasma-free metanephrines and serum chromogranin levels were normal. Whole-body 131I-MIBG scan including the retroperitoneal mass did not show any abnormal uptake. On excision, histopathology of this paravertebral abdominal mass revealed carcinoid tumor. We suggest the use of 68Ga DOTANOC PET/CT as a first-line imaging modality for localization of source of ACTH secretion in ectopic ACTH syndrome.

A 60-year-old woman with clinical and biochemical features suggestive of adrenal insufficiency was found to have bilateral adrenal masses on CT scan and was subjected to F-FDG PET scan. The scan showed hypermetabolic mediastinal nodes in addition to intense tracer uptake in bilateral adrenal masses. CT-guided adrenal biopsy grew Histoplasma capsulatum on Sabouraud dextrose agar culture. A second F-FDG PET scan after 6 months of appropriate antifungal therapy showed a significant decrease in intensity of uptake consistent with the clinical outcome.