Not Just a Birthmark: A Case Report of a Subtle Port-Wine Stain Heralding Sturge-Weber Syndrome

Sturge-Weber syndrome is a rare neurocutaneous disorder due to a somatic GNAQ mutation, which is characterised by facial capillary malformation, leptomeningeal angiomatosis, and possible ocular involvement. Identifying these faint birthmarks is important because even mild skin involvement may indicate significant underlying intracranial vascular malformations and early neurological complications. We report a seven-year-old boy with focal seizures beginning at two years of age, often progressing to generalised tonic-clonic events, and associated with intermittent left-sided headaches. Examination revealed a faint reddish discolouration over the left face, unnoticed previously by the parents. EEG demonstrated left temporoparietal epileptiform discharges, while MRI showed ipsilateral cerebral atrophy, leptomeningeal and pachymeningeal enhancement, choroid plexus enlargement, and cortical calcifications, confirming the diagnosis of Sturge-Weber syndrome. The patient was optimised on antiseizure medication and scheduled for annual ophthalmological surveillance. This case underscores the importance of considering SWS even when facial vascular lesions are minimal, as early recognition facilitates timely seizure management, counselling, and prevention of long-term neurological and ocular complications.