Graves' disease in the cervical thyroid and thyroglossal duct remnant: case report and review of literature.

OBJECTIVE: To describe a patient with a rare presentation of Graves' disease in the cervical thyroid and thyroglossal duct remnant.

METHODS: We present a detailed case report, including initial manifestations, laboratory findings, and radiologic evaluation of a patient with Graves' disease. A review of the relevant medical literature is included. A search for articles in the MEDLINE database from 1966 to November 2003 was performed with use of the following key words: thyroglossal duct remnant, thyroglossal duct cyst, thyrotoxicosis, Graves' disease, hyperthyroidism, and ectopic thyroid tissue. The reference lists from the articles obtained from the MEDLINE database were then reviewed for other pertinent articles. English abstracts of non-English articles were also reviewed.

RESULTS: A 63-year-old woman presented with thyrotoxicosis. Examination of her neck was notable for a 3.5-cm soft, mobile midline mass overlying the thyroid cartilage. She had no extrathyroidal manifestations of Graves' disease. The rest of the physical examination was unremarkable. Laboratory studies revealed a thyrotropin (thyroid-stimulating hormone) level of 0.01 microIU/mL (normal range, 0.3 to 6.6) and free thyroxine level of 4.7 ng/dL (normal range, 0.6 to 1.5). An ultrasound study showed a normal-appearing thyroid and an infrahyoidal neck mass (3.0 by 1.7 cm). A radioiodine (123I) thyroid scan demonstrated diffuse homogeneous uptake throughout the gland in conjunction with 66.6% uptake at 24 hours. In addition, a large rounded area of increased activity slightly left of the midline was noted. The left anterior oblique image showed that this area was not continuous with the left upper pole. We thought that this finding represented a hyperfunctioning thyroglossal duct cyst or remnant tissue. Our patient subsequently underwent radioiodine therapy with 15.56 mCi of 131I. A review of the English-language literature revealed only rare case reports of thyrotoxicosis in ectopic thyroid tissue.

CONCLUSION: Although the occurrence of thyrotoxicosis is common, to the best of our knowledge this is only the second case of Graves' disease involving the thyroglossal duct remnant reported in the English literature.