Postlaminectomy ossified extradural pseudocyst. Case report. A large ossified spurious meningocele accompanied by recurrent lumbar disc herniation occurred 7 years after posterior intervention for laminectomy and discectomy in a 53-year-old man. The cyst wall, histologically composed of mature bone tissue, was sparsely covered with connective tissue and lined with fibrocyte- or fibroblast-like cells on the inside. The ossified pseudocyst was presumed to have originated from a minute defect in the dura mater which occurred at the time of the first operation. 