History A 32 year old man was referred for consultation after three months of conservative treatment had failed to relieve low back pain with left sciatic pain to the toes. He denied any bowel orbladder control problems.
Fig. 1: Lumbar spine (9/18/84).
On initial physical examination, he had low back muscle tenderness without spasm. Straight leg raising on the left side produced left sciatic pain at 40° of elevation. The left Achilles tendon reflex was absent. Sensation on the lateral aspect of the left foot and calf was decreased. Motor examination was inconclusive.
The lumbar spine x-ray film showed no bone abnormalities or disc space narrowing (Fig. I ). A CT scan starting at the lower half of the body of L3 and continuing through the upper sacrum showed a slight central bulge at the L5-SI level (Fig. 2).
Fig. 2: CT scan (9/18/84).
Nonoperative treatment of restricted activities, nonsteroid anti-inflammatory drugs, and muscle relaxants were continued. Symptoms progressively improved and, six weeks later the patient was without symptoms and the straight leg raising test no longer produced sciatic pain but did produce back pain. The left Achilles tendon reflex was still absent and appreciation to light touch was still decreased on the lateral aspect of the left foot. The patient had returned to his sedentary occupation.
About three months after the initial consultation, the patient experienced an episode of lower back pain radiating to the left foot brought on by laughter. On closer questioning he admitted having had a vague uncomfortable feeling in the lower back for the past several weeks as well as pain in the anal area when coughing. He had had some problems sleeping at night because of back discomfort. Over the prior two weeks he admitted to having some problems initiating micturition.
Physical Examination The patient was in severe pain and had paraspinal muscle spasm as well as tenderness of the lumbosacral musculature. Straight leg raising reproduced the left sciatic pain at 30° of elevation and there was a positive crossover with straight leg raising on the right. Bowstring test was positive. He had decreased sensation of the lateral side of the foot as well as in the perineal area. Left Achilles tendon reflex was absent. No definite muscle weakness was detected.
Laboratory Studies Postvoiding residual determined by catheterization was 350 cc of urine.
A metrizamide myelogram done at this time showed an intradural filling defect, measuring 2.5 cm x 1.8 cm. at the level of the L3 vertebral body (Fig. 3). Metrizamide-enhanced CT confirmed the presence of this lesion (Fig. 4).
Treatment The diagnosis of an intradural extramedullary spinal cord tumor, thought to be a meningioma, a neurofibroma, or possibly an ependymoma, was established.
Neurosurgical consultation was obtained, and on surgical exploration, a firm, encapsulated reddish-brown lesion measuring about 2.5 cm in diameter was encountered (Fig. 5). A nerve fascicle was intimately attached to the capsule and had to be teased off Fig. 6). This lesion was then sectioned in the operating room. The gross inspection of the surgical pathology indicated that it was an encapsulated hematoma (Fig. 7). Histology confirmed this diagnosis.
Fig. 3: AP and lateral myelogram (12/84).
A young person presenting with low back and sciatic pain with appropriate neurologic effects leads the physician to think immediately of a herniated lumbar disc syndrome. This presumptive diagnosis should not lull one into not considering neurodiagnostic evaluation. In a neurosurgical practice a primary neurologic tumor is seen about four times a year, with intracranial tumors outnumbering intraspinal tumors by 10 to 1. A practical classification is to consider these tumors as extradural, intradural-extramedullary, or intradural-intramedullary. Each has a characteristic presentation and radiographic appearance on myelogram. The types of tumors that may be encountered at each level are summarized in the Table.
Extradural spinal cord tumors are encountered in more than 50% of cases . In descending order of frequency, they are found in the thoracic and lumbar areas. Most are metastatic from primary carcinoma of breast, lung, prostate, GI, renal and thyroid, and invade from surrounding tissue. Myeloma is notorious for direct invasion.
Fig. 4: CT scan (12/84).
Fig. 5: Intradural mass.
Fig. 6: Nerve fascicle and mass.
Fig. 7: Gross specimen.
Pain is the principal symptom and is described as aching and interfering with sleep. This pain indicates bone involvement. Nerve root compression occurs weeks to months later a manifested by focal weakness, numbness, atrophy and fasciculations.
SPINAL CORD TUMORS
The myelogram shows a characteristic pattern of a complete block with a paint-brush-stroke appearance. Treatment is decompression, with specific treatment for the individual tumor.
The intradural-extramedullary tumors comprise about 35% of spinal canal tumors. Meningiomas and neurofibromas are most frequently encountered. Ependymoma had a propensity for the lumbar spine. These tumors are associated with radicular and night pain. The tumors are slowly progressive, with the appearance of signs and symptoms being delayed. A myelogram shows the nerve root stretched out and in direct contact with a mass, causing a block. Treatment is total excision with the prognosis dependent on the tumor.
The intradural-intramedullary tumor occurs in about 15% of cases. The usual tumor is an ependymoma, astrocytoma, or glioma. Metastatic carcinoma can also be intradural and intramedullary. The hallmark of these tumors is a segmental differential sensory deficit, which is explained by the anatomic crossover of pain and temperature fibers and the ipsolateral pathway of proprioception and light touch. The course is insidious and usually painless. Myelography shows a characteristic diffuse dilation of the cord. Surgery is aimed at preserving function by removing the tumor mass.
The lesion encountered in this case was that of an intraduralextramedullary tumor. Histologic section showed an organized hematoma, which is a very rare tumor. In a recent review of the literature, only 85 cases have been reported, most in relation to a bleeding intraspinal neoplasm. Our case is especially unusual because there was no clotting abnormality or repeated lumbar punctures or arteriovenous malformation.
This case also points out the necessity of a complete physical examination. A CT scan was initially negative because the scan started just below the tumor, hence it was never visualized. Metrizamide myelogram followed by the enhanced CT scan provides a more complete diagnostic study. In this patient's case, the CT scan would have led to inappropriate therapy, whether lumbar laminectomy or chemonucleolysis.
1 . Connoly ES: Spinal cord tumors in adults, in Yowmans JR (ed): Neurological Surgery, ed 2, Philadelphia, WB Saunders Co1 1982. pp 3196-3214.
2. Davis RA, Washburn PL: Spinal cord meningiomas. Surg Gynecol Obstet 1970; 131:15-21.
3. Roscoe MW. Barrington TW: Acute spinal subdural hematoma: A case report and review of literature. Spine 1984; 9:672-675.
4. Rothman RH, Simeone FA, Bemini PM; Lumbar disc disease, in 7"Ai Spine, vol I. Philadelphia. WB Saunders Co, 1982. pp 508-645.
5. Simeone FA. Lawncr PM: Intraspinal neoplasms, in The Spine, vol 2. Philadelphia, WB Saunders. 1982. pp 1041-1054.
Section Editor: Eugene J. Dabezies, MD