Thyroglossal Duct Remnants
Pathology and Clinical Manifestations
The thyroid gland buds off the foregut diverticulum at the base of the tongue in the region of the future foramen cecum at 3 weeks of embryonic life. As the fetal neck develops, the thyroid tissue becomes more anterior and caudad until it rests in its normal position. The "descent" of the thyroid is intimately connected with the development of the hyoid bone. Residual thyroid tissue left behind in the migration may persist and subsequently present in the midline of the neck as a thyroglossal duct cyst. The mass is most commonly appreciated in the 2- to 4-year-old child when the baby fat disappears and irregularities in the neck become more readily apparent. Usually the cyst is encountered in the midline at or below the level of the hyoid bone, and moves up and down with swallowing or with protrusion of the tongue. Occasionally it presents as an intrathyroidal mass. Most thyroglossal duct cysts are asymptomatic. If the duct retains its connection with the pharynx, infection may occur, and the resulting abscess will necessitate incision and drainage, occasionally resulting in a salivary fistula. Submental lymphadenopathy and midline dermoid cysts can be confused with a thyroglossal duct cyst. Rarely, midline ectopic thyroid tissue masquerades as a thyroglossal duct cyst, and may represent the patient's only thyroid tissue. Therefore, if there is any question regarding the diagnosis or if the thyroid gland cannot be palpated in its normal anatomic position, it is advisable to obtain a nuclear scan to confirm the presence of a normal thyroid gland. Although rarely the case in children, in adults the thyroglossal duct may contain thyroid tissue that can undergo malignant degeneration. The presence of malignancy in a thyroglossal cyst should be suspected when the cyst grows rapidly, or when the ultrasound demonstrates a complex anechoic pattern or the presence of calcification.
If the cyst presents with an abscess, treatment should consist of drainage and antibiotics. Following resolution of the inflammation, resection of the cyst in continuity with the central portion of the hyoid bone and the tract connecting to the pharynx, in addition to ligation at the foramen cecum (the Sistrunk operation) is curative. Lesser operations result in unacceptably high recurrence rates, and recurrence is more frequent following infection. According to a recent review, factors predictive of recurrence included more than two infections prior to surgery, age under 2 years, and inadequate initial operation.
in all photos attachments : carcinoma arising in thyroglossal duct
Schwartz's Surgery 8e