Introduction: Post-traumatic leptomeningeal cysts are sequel of growing skull fractures (GSFs). Incidence is 0.05% to 0.1% of skull fractures. Intractable seizure, focal neurological deficits may be associated. This study elucidates clinicoradiological presentation of leptomeningeal cyst. Case Report: A 7year old female child presented with history of head injury on left side at 3months of age following which she developed swelling in left side of scalp. On eliciting history child had developed early left handedness. A localized well defined soft spherical swelling present in left parieto-occipital region on scalp about 3x4cm, nontender, nonpulsatile with a gap in between fractured bony margins. Skull xray showed lytic lesion with irregular sclerotic margins. CT showed hypodense lesion protruding through the calvarial break in left temporo-parietal region. MRI brain showed well defined cystic lesion with bevelled edges communicating with ipsilateral dilated occipital horn of lateral ventricle. The lesion is extending within the calvaria and extra-calvarially. Conclusion: Simple linear skull fracture in young children can produce GSF as late complication. Recognizing this rare unusual progression is crucial as early treatment prevents irreversible neurological sequel like seizures, paresis
