Pseudo-Lyre Sign

Abstract

To study the causes of the Pseudo- Lyre sign which is radiologically demonstrated in tumours other than the carotid body tumour. The study is based on an unusual case of neurofibroma of the cervical sympathetic chain presenting as a pulsatile mass in the carotid triangle in a 34 years female. Radiological investigation pointed to a diagnosis of a carotid body tumour because of typical splaying of the internal and external arteries causing the Lyre sign. At surgery, the tumour which was arising from the cervical sympathetic chain (CSC) was excised with minimum blood loss and histopathology confirmed it to be neurofibroma. This, we presume is the first ever report of a neurofibroma of the cervical sympathetic chain causing Lyre sign which we have referred to as Pseudo-Lyre sign. The various investigations which help in diagnosing the cause of Pseudo-Lyre sign have been discussed. All tumours causing Lyre sign on radio-imaging are not carotid body tumours. Other masses mostly neurogenic can demonstrate this sign and an attempt should be made preoperatively to confirm the diagnosis.

Keywords: Cervical sympathetic chain; Horner's syndrome; Lyre sign; Neurofibroma.

Fig. 1

CT Angigraph showing the Lyre’s sign. Inset: The Lyre

Fig. 2

Intra-operative view of the tumour splaying the ECA and ICA

Fig. 3

Intraoperative view after tumour removal

Fig. 4

The tumour after removal. The nerve (CSC) exiting the tumour (arrow)

Fig. 5

Post-operative photograph of the patient showing right-sided miosis and mild ptosis (Horner’s syndrome)