Thyroglossal duct cyst and second branchial anomalies are the most important congenital malformations of the neck with the leading symptoms 'tumors, cysts and sinuses of the neck' in childhood.

1. They disturb esthetic appearance;
2. may lead to carcinophobia of the parents;
3. are prone to complications, such as recurrent infections with abscess, hindering total excision.
4. Cancer in these malformations has been observed in adulthood.

They are vestigial elements of important developmental structures.

History: During the first year of life the parents observe a mass in the midline near the thyroid gland = thyroglossal duct cyst. During infancy or later a mass or a small opening with or without discharge of a watery secretion is observed along the sternocleidomastoid muscle = second branchial anomalies. Less often the general practitioner is consulted due to a localized infection mostly in the midline of the neck = infected thyroglossal duct cyst. Findings: Useful are the site and the findings on inspection and palpation of the present lesion. Midline location or lateral location from the earlap to the supraclavicular region.

In a supine position with a roll under the neck and the head inclined backward a tight cystic mass of the size of a hazel-nut up to a plum can be found near the hyoid or less frequent below it which moves during swallowing or sticking out the tongue. In acute or going down infection the local findings of the thyroglossal duct cyst may be blurred and there are local signs of infection or a secondary sinus. A small opening at the anterior border of the sternocleidomastoid muscle may be recognizable which delivers spontaneously or following striking out with a finger a watery mucus and which may be cannulated with a probe upward. Or a cystic mass without or combined with a sinus may be visible underneath the sternocleidomastoid muscle.

The cysts and sinuses do not disappear spontaneously. The former may become larger and all these anomalies are prone to lifelong complications.

Besides the individual local findings and the differentiation between congenital and acquired lesions the localization medially or laterally may be helpful in the differential diagnosis.
Midline: Epidermoid and dermoid cysts, cleft of the neck and ectopic thyroid gland at the base of the tongue are examples of congenital malformations; and pathologies of the thyroid gland especially in teenagers are examples of acquired midline lesions. Laterally to the midline: Preauricular sinuses and tags (the latter also at the neck), cystic lymphangioma and ectopic thymus belong to the congenital malformations, lesions of the salivary glands and lymphadenopathies to the acquired lateral lesions.

Often an ultrasound with Doppler is sufficient for work-up. A scintigraphy is necessary if there is no thyroid gland at the normal site, in case of hypothyroidism or a suspected neoplasm. In obscure local findings or cysts and sinuses of anusual localization (as in first branchial anomalies) a MRI is useful and a visualization of a sinus with a radiopaque fluid may be necessary.

Following diagnosis of a thyroglossal duct cyst or a second branchial anomaly a total excision is indicated, which belongs to a pretentious surgery; some important principles and the possible anatomical variants of these malformations have to be considered. In case of an inflammation antibiotics are necessary to avoid an incision; excision should be performed in the first infection-free period as in-patient in a tertiary center. Considerations of differential diagnosis (see differential diagnosis) may also lead to an indication for surgery.

Recurrences only in cases of previous infections and following inappropriate surgery (with resection of the hyoid only 1.8 percent recurrence. Bruns U et al. Otorhinolaryngol Nova /:155,1997).11