Objectives: Paraneoplastic Cushing syndrome is a rare condition, representing a small fraction of the adrenocorticotropic hormone (ACTH)-dependent cases of Cushing syndrome Methods: Four case descriptions and literature review, highlighting the diagnostic challenges and treatment options are presented.
Results: Different tumor types can be associated with ectopic ACTH secretion. The most common types are bronchial carcinoids and small cell lung carcinoma (SCLC). However, in approximately 10 to 20% of the cases, no overt tumor (occult tumor) can be found. The diagnosis is made in a multistep process. Firstly, hypercortisolemia and adrenocorticotropin hormone dependency have to be confirmed. Distinction between a pituitary or ectopic cause can be cumbersome. MRI of the pituitary gland, a corticotropin releasing hormone stimulation test and a sinus petrosus sampling can be used. Treatment options consist of tumor management, somatostatin analogs, steroidogenesis inhibitors, and bilateral adrenalectomy.
Conclusion: Clinicians should consider the diagnosis, and opt for specific treatment, especially in patients with a history of neuroendocrine tumors.
Keywords: 68-Ga-Dotatoc: somatostatin receptor ligand DOTA-D-Phy1-Tyr3-octreotide labeled with gallium-68; ACTH: adrenocorticopic hormone; CRH: corticotropin releasing hormone; CT-scan: computed tomography; Cushing syndrome; FDG-PET: fluorodeoxyglucose-positron emission tomography; MRI: magnetic resonance imaging; SCLC: small cell lung carcinoma; carcinoid; ectopic ACTH secretion; hypercortisolemia; neuro-endocrine tumor; paraneoplastic; small cell lung carcinoma; steroidogenesis inhibitors.