Multiple extradural arachnoid cysts: report of two operated cousin cases.

Study Design: Report of 2 operated cousin cases of the multiple spinal extradural arachnoid cysts.
Objective: To report the operative findings of cousin cases of the multiple spinal extradural arachnoid cysts and analyze a genetic etiology with the pedigree of all family members.
Summary of Background Data: Spinal extradural arachnoid cyst is a relatively rare condition that occupies the intraspinal space and sometimes causes neurologic disturbances. The exact etiology is unknown since most reported cases are sporadic. Minimally invasive treatments have been recently applied to a single extradural arachnoid cyst. However, it is still unknown which minimally invasive treatments can be applied to the multiple extradural arachnoid cysts.
Methods: We experienced 2 cousin cases of multiple spinal extradural arachnoid cysts. Operative findings were described. The pedigree of all family members was made, and a genetic etiology was discussed.
Results: Minimally invasive treatment was tried in Case 1. However, it failed to remove all cysts completely. Each cyst had each stalk communicating with subarachnoid space in both cases. Pedigree showed that the mode of inheritance was likely autosomal dominant.
Conclusion: When the cysts are multiple, it is necessary to identify a dural defect in each cyst. The etiology of the multiple extradural arachnoid cysts may be hereditary.