Leptomeningeal cysts secondary to trauma represent an extremely rare complication of calvarial fractures experienced during childhood. The early diagnosis and surgical treatment of such cysts can serve to prevent neurological sequelae. A 23-year-old male from a remote region attended the neurosurgery department complaining of headache, insomnia, and slowly progressing swelling over the right frontal region.The patient reported experiencing trauma (cow horn) in the same region of the head some 15 years previously.Non-contrast cranial computed tomography showed a lytic calvarial lesion with a large cystic area in the right frontal bone. Further, brain magnetic resonance imaging (MRI) revealed hyperintensity on the T2-weighted MRI and no enhancement on the T1-weighted post-contrast images. Moreover, there was no restricted diffusion corresponding to the cystic lesion in the frontal region. The dura mater and the bone gap were repaired using titanium mesh. The patient, whose headache and insomnia symptoms had completely disappeared, was discharged five days after the operation.