Unusual pattern of leptomeningeal cyst with herniation of porencephalic cyst

Abstract

BackgroundGrowing skull fracture or leptomeningeal cyst is an uncommon occurrence after severe head trauma in childhood. It is mostly observed in infants and children less than 3 years of age. Another uncommon complication of head trauma is development of porencephalic cyst.Case presentationWe present an unusual case of post-traumatic type III leptomeningeal cyst in a 9-month-old infant with history of head trauma 3 months ago. CT and MR imaging revealed widening of bony defect compared to previous imaging, and herniation of porencephalic cyst through the defect, leading to formation of a large cystic swelling in scalp. The 3 month delay in evaluation of the scalp swelling was due to lack of patient education after trauma, and no subsequent follow-up.ConclusionsKnowledge about etiopathogenesis and risk factors of leptomeningeal cyst development after head trauma ensures that close follow-up is done in such cases for early detection and management of growing skull fracture.