Ectopic thymic carcinoid masquerading as a thyroid nodule.

A 26-year old woman presented with a thyroid nodule. Ultrasound and scintigraphy confirmed the presence of a 3.5-cm non-functioning mass in the left lobe. A fine needle aspiration demonstrated unusual, malignant-appearing cells, and thyroidectomy was performed. At gross pathological sectioning, the lesion was clearly attached to, but not part of, the thyroid. Microscopic features indicated an atypical carcinoid arising in a cervical remnant of the thymus. This appears to be the first case of ectopic thymic carcinoid presenting as a thyroid nodule.