A challenging case of ectopic ACTH-dependent Cushing's syndrome due to medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is an infrequent neoplasm originating from thyroid parafollicular cells. Calcitonin production is its distinguishing feature [1]. Due to its neuroendocrine provenience, MTC can release different active agents. Uncommonly, it can be a source of adrenocorticotropic hormone (ACTH), accounting for about 2% of ectopic Cushing's syndrome (CS) [1]. We present a case of a 45-year-old male with an ectopic ACTH-dependent CS induced by MTC. The patient, with a history of recent diabetes and hypertension, suspicion of CS. He complained of increasing weakness, resonance imaging 2 years prior to admission.