J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.31.2.106 on 1 April 1968. Downloaded from J. Neurol. Neurosurg. Psychiat., 1968, 31, 106-109 Intramedullary cystic lesions of the conus medullaris SAMI I. NASSAR, JAMES W. CORRELL, AND EDGAR M. HOUSEPIAN From the Department of Neurosurgery, College ofPhysicians and Surgeons, Columbia University, and the Neurological Institute of the Columbia-Presbyterian Medical Center, New York, U.S.A. Intramedullary cystic lesions of the conus medullaris of the aetiology, these cysts may simulate the clinical are rare. Although an extensive literature describes picture of syringomyelia. syringomyelia as being a frequent basis for cystic The cases of cysts of the conus medullaris re- cervico-thoracic lesions it is apparent that this ported here simulated the clinical picture of does not occur frequently in the lumbosacral region syringomyelia, tumour, or lumbar disc disease. (Kirgis and Echols, 1949; Netsky, 1953; Rand and The radiographic findings in each case were inter- Rand, 1960; Love and Olafson, 1966). Poser (1956), preted as indicating the presence ofan intramedullary in a review of 234 cases of syringomyelia, found tumour. The correct diagnosis was made in each that the cavity extended into the lumbosacral region case only at operation. in only 12-6% and in only five cases were the Protected by copyright. cavities restricted to the lumbosacral segments. Some authors (Thevenard, 1942; Andre, 1951) CASE REPORTS question the occurrence of syringomyelia in the lower spinal cord. Nevertheless a high incidence CASE 1 (F.T., NO. 179 16 92) A 22-year-old negro male of constitutional defects has been noted among was admitted complaining of weakness and pain in the syringomyelia patients and members of their legs for three years. The pain began in the right foot and of which are bifida progressed in nine months to involve both lower limbs. families, the most frequent spina There was an associated feeling of numbness of both feet. occulta,pes cavus, syndactylism, andchestdeformities One year before admission he complained of persistent (Henneberg and Koch, 1923; Chavany and Thiebaut, low backache which radiated to the right thigh and calf. 1933; Thevenard and Coste, 1935; Jackson, 1949). This was followed by difficulty in voiding. The patient These defects have been found to occur at times with also observed a progressive bilateral deformity of the cystic cavitations of the lumbosacral region, lending feet (pes cavus). His past medical history contributed support to the developmental aetiology of at least nothing. some intramedullary cysts. General physical examination was normal. On neuro- Localized cysts of the conus and epiconus have logical examination this asthenic young man was found also been reported in association with trauma, to have bilateral foot drop. There was diffuse weakness http://jnnp.bmj.com/ and of both lower extremities, most marked in the calf tumours, and vascular disease (Kirgis Echols, muscles. There was wasting of the small muscles of both 1949; Netsky, 1953; Hughes, 1966). Haemorrhage feet, more pronounced on the right. The Achilles reflexes into the substance of the-cord has been described were absent. The appreciation of pain and light touch as a cause of cavitary disease following severe was decreased up to the level of L3 bilaterally, but the trauma. Liquefaction of the haemorrhage results third to the fifth sacral dermatomes were spared. Labora- in the formation of a fluid-filled cavity that may tory studies were normal. The cerebrospinal fluid remain unchanged or slowly enlarge at the expense contained 17 mg protein 100/ml./cu.mm and 1 W.B.C. offunctioning neural elements. Sudden haemorrhage, Pantopaque myelography showed evidence of an on September 28, 2021 by guest. of course, results in a rapid progression of neuro- intramedullary tumour of the conus (Fig. la). At laminec- of haemato- tomy (Tl1-LI) a 2 x 2 cm intrinsic mass ofthe conus was logical symptoms and the syndrome found ending in the filum (Fig. lb). The nerve roots were myelia. stretched over the mass, which was cystic. A number 26 Cavitations may also be produced by vascular needle was inserted into the mass and 4 ml. of colourless impairment to the cord structure from extraneural fluid was aspirated. The mass collapsed and the nerve inflammatory or compressive pathology. Another roots became relaxed. A 1 cm linear incision made in the process of cyst formation may be ischaemic necrosis dorsal midline of the conus allowed inspection of the of the cord with resulting liquefaction. Irrespective cavity in which there was no gross evidence of tumour, 106 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.31.2.106 on 1 April 1968. Downloaded from Intramedullary cystic lesions of the conus medullaris 107 FIG. la. Case 1: myelographic demonstration of the FIG. lb. Casel:anintrinsiccysticmassoftheconuswith intramedullary mass defect at the level of T12-LL. the stretched nerve roots overlying it exposed at operation. Protected by copyright. http://jnnp.bmj.com/ FIG. 2a. Case 2: myelographic demonstration of a FiG. 2b. Operative photograph showing a cyst of the on September 28, 2021 by guest. fusiform intramedullary tumour at the level of T12-LJ conus which has been opened and its cavity exposed. with a complete block to the flow ofPantopaque above. and cell block of the cyst fluid was negative for tumour CASE 2 (C. D., NO. 174 92 23) A 51-year-old woman was cells. No biopsy of the cyst wall was done. The post- admitted because ofepisodic low back pain with radiation operative course was uneventful. A follow-up of seven to the right lower extremity for eight years. In December months showed an improvement in motor, sensory, and 1963 the patient noted weakness in the right leg. In 1964 bladder function. a 'disc operation' carried out in another hospital was J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.31.2.106 on 1 April 1968. Downloaded from 108 Sami l. Nassar, James W. Correll, and Edgar M. Housepian followed by temporary alleviation of the low back pain but she continued to complain of weakness in the right leg and began to have numbness of the right foot and toes. Several months before this admission the patient also complained of pain in the left leg. Her past medical history contributed nothing. On physical examination there was flattening of the lumbar lordosis with moderate paraspinous spasm and tendemess in the lumbar region. There was a right foot drop with wasting of the anterior and posterior tibial peronei and extensor hallucis longus muscles on the right. Hypaesthesia was noted in the L5 dermatome in the right foot. The right Achilles tendon reflex was absent. The rest of the neurological examination was normal. Laboratory data were normal. A radiograph of the spine showed slight narrowing of the lumbosacral inter- space. The cerebrospinal fluid protein level was 28 mg/ 100 ml. W.B.C. 1; R.B.C. O/cu.mm. A Pantopaque myelogram revealved a large tumour of the conus with complete block at T12-L1 (Fig. 2a). At laminectomy (Ti1-LI) a large cyst of the conus medullaris was found. The cyst was entered through a thinned portion of the conus and 15 ml. of clear, colour- less watery fluid was drained. Careful inspection of the FIG. 3. Case 3: operative exposure ofa rounded lobulated cavity failed to reveal evidence of tumour (Fig. 2b). cystic mass adherent to the inferior aspect of the conus Biopsy of the cyst wall was negative for tumour and medullaris. Protected by copyright. showed only fragments of white matter. In the post- operative period, numbness and pain gradually disap- rounded opening, suggesting a greatly dilated central peared. The strength of the right leg improved with canal, in the conus medullaris. A subtotal excision of the physiotherapy. The patient is doing well one year after cystic lesion was done and the conus medullaris and operation. cauda equina were decompressed. Microscopic examination of the cyst removed at CASE 3 NO. 158 operation showed that the wall of the cyst was formed by (A. L., 74 76) A 16-year-old boy was a of noted to have a mild thoraco-lumbar scoliosis at the age layer ependymal cells situated along one surface of of 3. He was well and engaged in various narrow bands of glial tissue and it was concluded,that sport activities this was a cystic congenital malformation of the filum until he was 14 years old when the scoliosis progressed terminale. rapidly. In June of 1962 a spinal fusion from T6 to T11 The was done. On the second post-operative day the patient post-operative course was uneventful except for was unable to move his lower limbs: there was diffuse a urinary tract infection. Post-operatively the boy was weakness and spasticity of the muscles of the lower able to walk unassisted for short distances. In December extremities, most marked in the of 1966 the patient was reported to be attending college. quadriceps, hamstrings Although a leg brace was used he was able to carry out and iliopsoas on the left and the plantar and dorsiflexor http://jnnp.bmj.com/ muscles of the left foot were profoundly weak. There all desired activities. were bilateral Babinski signs and unsustained ankle clonus on the right. Position and vibration sense were DISCUSSION asymmetrically reduced in the lower extremities. The patient required bladder drainage. These patients presented with interesting and similar The cerebrospinal fluid protein level was 51 rng/ features. All three had lumbar pain and paresis 100 ml., and 1 W.B.C. and 5 R.B.C./cu.mm. Radio- of the lower extremity, thought to be related to graphs of the vertebral column showed marked right tumour, intervertebral disc disease, and syringo- T11-12 scoliosis.