Adrenocorticotropic hormone--producing thymic carcinoid in a teenager.

Carcinoid of the thymus rarely occurs during childhood. The authors identified eight cases in patients younger than 17 years of age. All were associated with Cushing syndrome. Adrenocorticotropic hormone (ACTH) produced by the tumor may be released intermittently, delaying the findings of Cushing syndrome. The authors describe a case of ectopic ACTH production in a teenaged boy who had longstanding hyperpigmentation, increased ACTH levels, and normal cortisol levels. Magnetic resonance imaging of the pituitary had normal findings. Subsequently, severe Cushing syndrome developed. Computed tomography (CT) scans of the chest showed a mediastinal mass that proved to be a thymic carcinoid. The lesion was inoperable. Radiation and chemotherapy were of limited benefit. Metyrapone was used to control hypercortisolism. The patient died with extensive metastases 6 years after initial presentation. CT scans of the chest should be performed in an attempt to localize ectopic ACTH-producing tumors. Surgical excision of the lesion is the treatment of choice. Control of hypercortisolism is essential.