Objective: Ectopic adrenocorticotropic hormone secretion/syndrome (EAS) is caused by excess secretion of ACTH leading to hypercortisolism by non-pituitary, commonly malignant origins. We present a rare case of esthesioneuroblastoma (ENB) complicated by EAS in the follow-up period.

Methods: A child presented with nasal obstruction at the age of 10 months. Polypoid mass obstructing the right nasal passage was detected. Magnetic resonance imaging (MRI) showed a lesion limited within the nasal cavity. The lesion was completely removed by nasal endoscopic surgery. The pathologic examination revealed a diagnosis of esthesioneuroblastoma. It was confined to the nasal cavity so chemotherapy/radiotherapy was not administered and began to follow up. At 28 months of age, he presented with rapid weight gain. Laboratory data were consistent with Cushing's syndrome (CS). High-dose dexamethasone suppression test and imaging studies led us to think of ectopic ACTH syndrome originated from ENB relapse. After partial resection of the tumor, ketoconazole treatment was started along with chemotherapy. Hypercortisolemia was kept under control with ketoconazole treatment as long as the treatment was maintained.

Conclusions: Cushing syndrome is a rare endocrine disorder. Adrenal sources of hypercortisolism and ectopic sources of ACTH overproduction should be investigated especially in young children.