An infected branchial cyst complicated by retropharyngeal abscess, cervical osteomyelitis and atlanto-axial subluxation.

We present a case of a 44-year-old man who visited his general practitioner for recurrent neck swelling, which was found to be a neck abscess. It was aspirated, later recurred, and then surgically excised. Histology was consistent with an infected branchial cyst. Eight months after discharge, the patient presented with a history of progressive neck pain and stiffness and eventually bilateral upper limb weakness. MRI demonstrated a prevertebral abscess complicated by cervical osteomyelitis and atlanto-axial instability. The abscess was drained and appropriate antibiotic treatment was administered. The patient responded well with full recovery of his upper limb strength and resolution of the abscess. However, he had mild persistent neck stiffness.