N-of-1 trials can serve as useful tools in managing rare disease. We describe a patient presenting with a typical clinical picture of Cushing's Syndrome (CS). Further testing was diagnostic of ectopic Adrenocorticotropic Hormone (ACTH) secretion, but its origin remained occult. The patient was offered treatment with daily pasireotide at very low doses (300 mg bid), which resulted in clinical and biochemical control for a period of 5 years, when a pulmonary typical carcinoid was diagnosed and dissected. During the pharmacological treatment period, pasireotide was tentatively discontinued twice, with immediate flare of symptoms and biochemical markers, followed by remission after drug reinitiation. This is the first report of clinical and biochemical remission of an ectopic CS (ECS) with pasireotide used as first line treatment, in a low-grade lung carcinoid, for a prolonged period of 5 years. In conclusion, the burden of high morbidity caused by hypercortisolism can be effectively mitigated with appropriate pharmacological treatment, in patients with occult tumors. Pasireotide may lead to complete and sustained remission of hypercortisolism, until surgical therapy is feasible. The expression of SSTR2 from typical carcinoids may be critical in allowing the use of very low drug doses for achieving disease control, while minimizing the risk of adverse events.
Keywords: Carcinoid; Ectopic Cushing’s syndrome; Lung carcinoid; Pasireotide; Thoracic neuroendocrine tumor.