Dear Sirs,

I read with great interest the recent article by Islam et al. on aberrant anatomy of the hypoglossal nerve.Reference Islam, Walton and Howe¹ Interestingly, one rare and often overlooked cause of hypoglossal paresis is Collet–Sicard syndrome.

This syndrome involves unilateral cranial nerve palsies affecting the IXth to XIIth nerves. It may occur secondary to malignancies such as fibro-sarcoma.Reference Petrovic, Grozdanovic, Kovacevic, Visnjic and Petrovic² Similarly, schwannomas of the cranial nerves, such as the hypoglossal nerve, can cause Collet–Sicard syndrome. There have been reports of this syndrome occurring secondary to glomus tumours.Reference Garcia-Escriva, Pampliega, Martin-Estefania and Botella³ Metastasis to the skull base can result in the rapid development of Collet–Sicard syndrome. It may occur secondary to neck trauma;Reference Jimenez-Caballero, Marsal-Alonso, Mendez-Cendon and Alvarez-Tejerina⁴ for instance, Battaglia et al.Reference Battaglia, Martini and Tannier⁵ recently described the case of a 57-year-old man with neck trauma who developed Collet–Sicard syndrome secondary to dissection of the carotid artery. The syndrome may also occur secondary to infectious agents; for instance, untreated otitis media can spread to the cervical region, resulting in cervical instability and Collet–Sicard syndrome.

Patients with Collet–Sicard syndrome usually complain of dysphagia with concurrent hoarseness of voice. Unilateral neck pain may be present. Rarely, Collet–Sicard syndrome may be the initial presentation that leads to the diagnosis of an underlying malignancy. For instance, Villatoro et al.Reference Villatoro, Romero and Rueda⁶ recently described the case of a 70-year-old man found to have Collet–Sicard syndrome, which on further evaluation was revealed to be secondary to metastatic prostatic carcinoma. Absence of sympathetic system features helps to distinguish Collet–Sicard syndrome from other syndromes such as Villaret syndrome.Reference Lucato, Passos, Campos, Conforto and McKinney⁷

Computed tomography imaging goes a long way in making the current diagnosis. Magnetic resonance imaging gives an even better idea of the extent of the underlying lesion.Reference Climans, Melanson and Desai⁸ Surgical removal of the underlying tumour may result in resolution of symptoms. Long-term antibiotic therapy may be needed in infectious cases. Sibai et al.Reference Sibai, Ben-Galim, Eicher and Reitman⁹ recently reported the case of a 56-year-old man with infectious Collet–Sicard syndrome who required simultaneous posterior cervical debridement.

As is obvious from the above discussion, Collet–Sicard syndrome is a rare but serious cause of hypoglossal paresis. Clinicians should keep it high on the differential diagnosis when encountering patients with new hypoglossal nerve symptoms.