A thyroglossal cyst is a smooth, painless, subcutaneous lump which usually lies on the thyroid cartilage just to one side of the midline (G, Fig. 21-13). These cysts occur in both sexes equally, usually between the ages of 15 and 40, and are formed from the epithelial pouch that gives rise to the thyroid gland. This runs from the junction between the anterior two-thirds and the posterior third of the tongue (the foramen caecum, 21-13), to the pyramidal lobe of the thyroid, just above the isthmus. Cysts sometimes occur within the pyramidal lobe, or in relation to the hyoid bone.
Excision is usually not difficult. Occasionally, however, an extension of the cyst goes up to and through the hyoid bone, which may need to be divided, so refer the patient if you can. If you cannot refer him, proceed as follows.
THYROGLOSSAL CYST ANAESTHESIA. (1) General anaesthesia with intubation (A 13.1). (2) Intravenous ketamine (A 8.2). (3) Local anaesthesia (A 5.4).
INCISION. Make a 6[nd]8 cm transverse incision in a skin crease over the swelling. Separate the tissues between the patient's strap muscles in the midline longitudinally. If exposure is inadequate, divide these muscles transversely. Also divide the pretracheal fascia covering the cyst. Dissect it out with scissors.
Close the wound in layers. Approximate his strap muscles with 3/0 plain catgut, and his skin with 3/0 or 4/0 monofilament. Remove the sutures on the 5th day.
If an extension of the cyst extends up into his neck through his hyoid bone (uncommon), follow it upwards and divide his hyoid bone if necessary. No vital structures are in the way, and his divided hyoid does not need repair. If a remnant is left behind the cyst may recur.