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Congenital neck masses: thyroglossal duct cyst, branchial remnants and lymphatic malformations
The site of the mass gives away its origin: midline and rising on tongue protrusion — thyroglossal duct cyst (Sistrunk operation); at the anterior border of the sternocleidomastoid — a second branchial arch remnant; and on the left with recurrent thyroiditis — a pyriform sinus fistula.
Why it matters in the exam
Thyroglossal duct cyst is the commonest congenital midline mass; it moves up on swallowing and tongue protrusion because of its link to the hyoid bone. Before surgery, ultrasound confirms a normal thyroid gland in place. The operation is Sistrunk — excision of the cyst, the middle part of the hyoid bone and the tract to the tongue base; excising the cyst alone leads to recurrence. In about 1% a carcinoma is found (usually papillary). A dermoid cyst also lies in the midline but does not move with the tongue.
Second branchial arch remnants are the commonest (about 95%): a mass or opening at the anterior border of the sternocleidomastoid, with a tract that climbs between the internal and external carotid arteries, over nerves XII and IX, to the tonsillar fossa. First arch remnants lie near the ear and the angle of the mandible (Work type I and II), and their relation to the facial nerve requires care in surgery. Third and fourth arch remnants present as a pyriform sinus fistula, almost always on the left, with neck abscesses or recurrent acute thyroiditis; treatment is endoscopic cautery of the opening.
A lymphatic malformation ("cystic hygroma") is a soft mass present at birth or in the first two years; the macrocystic form responds well to sclerotherapy (OK-432 or doxycycline), and the microcystic form is treated with sirolimus or surgery. In a child with a neck mass the commonest cause is a reactive lymph node; warning signs of malignancy: a mass over 2 to 3 cm, a supraclavicular site, a hard fixed mass, systemic symptoms, rapid growth or no improvement after 6 weeks. Atypical mycobacteria: a toddler with a painless node and violaceous skin over it — the preferred treatment is excision.
Key points
- Midline and rising with the tongue — thyroglossal, Sistrunk.
- Anterior border of the sternocleidomastoid — second arch.
- Left with thyroiditis — pyriform sinus.
- Lymphatic malformation — sclerotherapy or sirolimus.
- Warning signs: over 2 to 3 cm, supraclavicular, 6 weeks.
Summary table
| Mass | Site and clue | Treatment |
|---|---|---|
| Thyroglossal duct cyst | Midline, rises on tongue protrusion | Sistrunk after thyroid ultrasound |
| Dermoid cyst | Midline, does not move with the tongue | Excision |
| Second arch remnant | Anterior border of the sternocleidomastoid | Excision of cyst and tract |
| First arch remnant | Near the ear and the angle of the mandible | Excision with facial nerve identification |
| Pyriform sinus fistula | Left side, recurrent abscesses and thyroiditis | Endoscopic cautery |
| Lymphatic malformation | Soft mass from birth | Sclerotherapy, sirolimus or surgery |
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Sources
- Cummings Pediatric Otolaryngology, 2nd edition (2021) — Congenital and acquired neck masses in children
- Nelson Textbook of Pediatrics, 22nd edition (2024) — Neck masses
- ISSVA Classification of Vascular Anomalies, 2018 — Lymphatic malformations
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.