A Case of Ectopic Hamartomatous Thymoma Occurring in the Neck

Abstract

Ectopic hamartomatous thymomas (EHT) is an extremely rare disorder. We report herein on a case of EHT occurring in the neck with a review of the literature. A 35 year-old man first noticed a swelling in his left cervical region at the beginning of March, 2005, and he came for a checkup in our department in March. In the initial examination, palpation revealed a 3×5 cm soft mass with a somewhat indistinct border in the left pars supraclavicularis plexus brachialis. There was no subjective symptom except swelling, and palpation revealed no anomaly in the cervical lymph nodes, and no other lesion was seen in the head and neck area. A tumor was present within the sternocleidomastoid muscle outside the left lobe of the thyroid gland, and the MRI imaging did not show any involvement of the thyroid gland. We performed a tumorectomy under general anesthesia. There was a tumor right under the sternocleidomastoid, there was no adhesions seen at the periphery of the tumor, and tumor removal went smoothly. The histological diagnosis was an ectopic hamartomatous thymoma. In 1984, Rosai et al. proposed the concept of the EHT as a lesion having the character of both a hamartoma and a tumor also comprising cervical ectopic thymic tissue. No recurrence has been reported in cases where the tumor has been totally extirpated. In our present case, no recurrence has been seen in a 7-year postoperative follow-up.