Occipital post-traumatic intradiploic arachnoid cyst converted to pseudomeningocele after re-trauma: a rare complication of rare pathology.

Background: Growing skull fracture (GSF)/pseudomeningocele is a rare complication of head injury in children. Post-traumatic intradiploic arachnoid cyst (PTIAC) is a variant but it is extremely rare. PTIACs are usually asymptomatic or with mild symptoms like headache. The rupture of PTIAC due to re-trauma leading to pseudomeningocele formation has not been seen or reported before.
Patient and Method: We present a case of occipital PTIAC where pseudomeningocele developed after re-trauma, and discuss the pathogenesis and management.
Result: En masse removal of the ruptured PTIAC was performed along with dural-defect repair. The post-operative recovery was good.
Conclusion: PTIAC is an extremely rare occurrence as a variant of GSF. It is usually asymptomatic, but it may rupture with trivial trauma due to a thinned-out outer table and then converts into pseudomengocele. En masse excision with dural-defect repair gives good results in cases of ruptured PTIAC due to re-trauma.