Neck cysts and paraganglioma
- Lesion
Lumps unique to the neck: embryonic remnant cysts at the side or midline, and paragangliomas at the carotid bifurcation.
What it is
Most neck masses are lymph nodes, thyroid or skin lesions covered elsewhere. A few lesions are particular to the neck: branchial cleft cysts on the lateral neck, thyroglossal duct cysts in the midline, and paragangliomas of the parasympathetic paraganglia, the carotid body tumour being the typical one. In adults, a lateral cystic neck mass must be distinguished from a cystic metastasis of HPV-positive carcinoma.
Structure
- Branchial cyst: well-circumscribed cyst of a few centimetres, watery or mucoid content, lymphoid wall.
- Thyroglossal cyst: cyst lined by squamous or respiratory epithelium, thyroid follicles in the wall in some.
- Carotid body tumour: red-pink to brown, well-vascularised mass enveloping the carotid bifurcation.
- Zellballen: rounded nests of chief cells with clear or granular cytoplasm, separated by delicate vascular septa, rimmed by sustentacular cells.
Step by step
- Incomplete obliteration of the second branchial cleft leaves an epithelial remnant that fills with fluid later in life.
- The thyroglossal duct normally disappears after the thyroid descends; a persisting segment forms a cyst.
- Paraganglia are neuroendocrine cells of neural crest origin that sense oxygen (carotid body).
- Loss of succinate dehydrogenase causes succinate to accumulate and mimics hypoxia (pseudohypoxia), driving chief cell growth.
- Chronic hypoxia (high altitude) is also associated with carotid body hyperplasia and tumours.
Congenital and neuroendocrine neck masses
| Lesion | Position | Origin | Key feature |
|---|---|---|---|
| Branchial cleft cyst | Lateral, anterior to sternocleidomastoid | Second branchial cleft | Lymphoid tissue in the wall |
| Thyroglossal duct cyst | Midline, near the hyoid | Thyroid descent tract | Moves with swallowing |
| Carotid body paraganglioma | Carotid bifurcation | Paraganglion (neural crest) | Zellballen; SDH mutations |
Markers
- Chromogranin
- Synaptophysin
- S-100 (sustentacular cells)
- SDHB
Clinical notes
- A lateral neck cyst in an adult over 40 is a cystic nodal metastasis (often HPV-positive oropharyngeal SCC) until proven otherwise.
- Thyroglossal cysts may become infected; surgery removes the cyst with the middle of the hyoid (Sistrunk).
- Carotid body tumours are painless, pulsatile, mobile side to side but not up and down; rarely secrete catecholamines.
Test yourself
Think of the answer, then tap the question to see it.
Where does a thyroglossal duct cyst occur and why does it move with swallowing?
In the midline near the hyoid bone; it is attached to the tract of thyroid descent and to the hyoid, so it rises with swallowing and tongue protrusion.
What are zellballen?
Nests of neuroendocrine chief cells separated by delicate vascular septa, the typical pattern of paraganglioma.
Which gene family is mutated in hereditary head and neck paragangliomas?
The succinate dehydrogenase (SDH) genes; SDHB mutations carry the highest risk of metastasis.
Elsewhere in DurgiPedia
- Branchial cleft cysts, sinuses and fistulas
- Thyroglossal duct cyst and ectopic thyroid
- Pharyngeal clefts and membranes: external ear and cervical sinus
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Hereditary paraganglioma-pheochromocytoma: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2025); Lymphadenopathy (StatPearls (NCBI Bookshelf), 2025).
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Representative model, for educational purposes only.