Lumbar and sacral cysts of meningeal origin.

Abstract

An infrequent cause of low back pain, only recently described, is the presence of a meningeal cyst within the lumbar or sacral canal. Although spinal extradural cysts causing cord compression were reported in the literature as far back as 1898 (4), no reference to meningeal cysts in the sacral and lumbar regions appeared prior to 1951. This is due probably to a lack of cognizance of such lesions or to a failure to appreciate the significance of minor myelographic defects which were not compatible with herniated disk or tumor. In 1951, Schreiber and Haddad (5) reported 4 cases of lumbosacral cyst which produced pain. In 2 of these, however, the diagnosis is inacceptable: histologic examination of one specimen revealed it to be a nerve root swollen by hemorrhage, while in the other instance the lesion was described by the surgeon as “a bruised swelling in the nerve.” Thus only 2 of the cases were actually meningeal cysts. Much earlier than this report, another entity was described which, though different, might well be confused with a meningeal cyst. Tarlov, in 1938 (6), described a pathologic entity which he called “perineurial cyst.” Ten years later (7) he reported a case with a typical disk syndrome relieved by excision of a perineurial cyst of the second sacral posterior nerve root and ganglion. We have recently encountered 5 examples of lumbar and sacral meningeal cysts, 4 of which were proved by surgery. The symptoms were vague, and no typical clinical picture could be constructed. Case I: M. O., a 36-year-old Negro male, was admitted to Montefiore Hospital on Oct. 27, 1950. He had been well until January 1948, when he twisted his back while at work. He immediately suffered sharp, severe, low back pain, which persisted. It was relieved by bed rest and aggravated by standing. On occasion, bending over caused pain down the back of both lower extremities. Examination showed forward flexion of the spine to be moderately limited. Straight leg raising was unimpaired but painful on the left side. Percussion over the sacrum produced local pain. No reflex or sensory changes could be demonstrated. Myelography, Oct. 28, 1950, revealed asymmetry of the extreme caudal end of the sac in both anteroposterior and right posterior oblique studies. Compression of the left side of the column was demonstrable in the latter view (Fig. 1). The defects were thought to be due to extrinsic pressure and the presence of a sacral perineurial cyst was considered. On Nov. 1, 1950, a sacral laminectomy was performed. The sacral canal was found to be widened, and a cyst measuring approximately 1.5 cm. in its greatest diameter was uncovered.