Lyre sign – Where schwannoma mimics a carotid body tumour

Abstract

Nerve sheath tumours arising from the sympathetic chain are extremely rare and present a diagnostic challenge. We report the case of a 31-year-old man who presented with an asymptomatic right cervical swelling. He was evaluated with sonography, CT, MR and angiography. Surgical excision of the lesion was performed, and histological examination revealed a schwannoma. The differential diagnosis of such tumours and their management are discussed. Imaging features of carotid body tumours and parapharyngeal schwannomas can be similar, as both can cause splaying of the carotid bifurcation, resulting in the lyre sign. This is illustrated by the case of a 42-year-old female who presented with a left neck swelling. Tumour was surgically excised, and histologic examination confirmed a schwannoma.

Contribution: This article highlights another cause of the lyre sign besides carotid body tumours and their relationship to carotid bifurcation on radiological imaging.