68ga-dotanoc and ACTH-Syndrome--Ectopic

Malignant tumors account for most sources of ectopic ACTH Cushing syndrome (EA-CS). Early localization of the source and complete removal can be curative and also prevent metastasis. Diagnostic CT is known to perform better than PET/CT (low dose) in characterizing lung pathologies. However, bronchial carcinoids, a common source of EA-CS, may be difficult to detect on chest CT scan especially when it is small and located close to the hilar region. We present a case of EA-CS due to bronchial carcinoid, which was easily seen on Ga DOTANOC PET/CT after a diagnostic chest CT was reported as normal.

Topics: ACTH Syndrome, Ectopic; Bronchial Neoplasms; Carcinoid Tumor; Cushing Syndrome; Female; Humans; Middle Aged; Organometallic Compounds; Positron Emission Tomography Computed Tomography; Radiopharmaceuticals

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.

Topics: 3-Iodobenzylguanidine; ACTH Syndrome, Ectopic; Adult; Carcinoid Tumor; Female; Humans; Multimodal Imaging; Organometallic Compounds; Positron-Emission Tomography; Retroperitoneal Neoplasms; Tomography, X-Ray Computed

We report a rare case of ectopic adrenocorticotropic hormone (ACTH) syndrome caused by a metastatic neuroendocrine tumor (NET) of the pancreas detected by PET/CT using different tracers. A 43-year-old female patient with Cushing syndrome (CS) by suspected ectopic ACTH secretion underwent a 68Ga-DOTANOC and a 18F-FDG PET/CT. Both these functional imaging techniques revealed increased tracer uptake in a pancreatic mass and multiple liver metastases. Histology showed the presence of a mildly differentiated pancreatic NET. 68Ga-DOTANOC PET/CT may be a useful functional imaging method, complementary to 18F-FDG PET/CT, in detecting ACTH-secreting pancreatic NETs.

Topics: ACTH Syndrome, Ectopic; Adult; Cell Differentiation; Female; Fluorodeoxyglucose F18; Glucose; Humans; Multimodal Imaging; Neoplasm Metastasis; Neuroendocrine Tumors; Organometallic Compounds; Pancreatic Neoplasms; Positron-Emission Tomography; Tomography, X-Ray Computed

Ectopic adrenocorticotropic hormone (ACTH)-secreting tumors account for approximately 10% of Cushing's syndrome (CS). We present an extremely rare case of a patient with CS caused by an ectopic ACTH-secreting pituitary adenoma (EAPA) of the ethmoid sinus. The tumor was identified by positron-emission tomography-computed tomography (PET/CT) using the somatostatin receptor analogue Ga-68-DOTANOC. Transnasal endoscopic resection was performed and the patient showed significant clinical improvement with normalization of the endocrine pituitary axis. Immunostaining showed a somatostatin receptor 2 and 5-positive ACTH-producing adenoma. In patients with ectopic ACTH secretion, Ga-68-DOTANOC-PET/CT may play an important role in the localization of EAPA. Transnasal endoscopic resection is the therapy of choice.

Topics: ACTH Syndrome, Ectopic; ACTH-Secreting Pituitary Adenoma; Adenoma; Adrenocorticotropic Hormone; Diagnosis, Differential; Gallium Radioisotopes; Humans; Male; Middle Aged; Multimodal Imaging; Organometallic Compounds; Paranasal Sinus Neoplasms; Positron-Emission Tomography; Tomography, X-Ray Computed