Fifty-nine cases of vertebral hemangioma were seen at the Mayo Clinic between 1980 and 1990. Vertebral hemangiomas were discovered incidentally in 35 patients, while pain was the presenting complaint in 13 patients. Five patients presented directly with progressive neurological deficit requiring surgery, and six patients had surgery elsewhere for spinal cord compression and were referred for follow-up evaluation. To better define the natural history of these lesions, a historical review of these patients was conducted; progression of an asymptomatic or painful lesion to neurological symptoms was found in only two cases (mean follow-up period 7.4 years, range 1 to 35 years). New-onset back pain followed by subacute progression (mean time to progression 4.4 months, range 0.25 to 12 months) of a thoracic myelopathy was the most common presentation for patients with neurological deficit. Initially, all 11 patients with spinal cord compression underwent decompressive surgery with full neurological recovery. Recurrent neurological symptoms were observed in three of six patients following subtotal tumor resection and postoperative administration of 1000 cGy or less radiation therapy (mean follow-up period 8.7 years, range 1 to 17 years). No recurrences were noted in four patients who had subtotal excision plus radiotherapy between 2600 and 4500 cGy. One other patient had gross total tumor removal without radiotherapy and has not had a recurrence. Based on these patients and a review of the literature, the authors recommend annual neurological and radiological examinations for patients with hemangiomas associated with pain, especially young females with thoracic lesions in whom spinal cord compression is most likely to develop. Radiation therapy or embolization is an effective therapeutic alternative for patients with severe medically refractory pain. Regular follow-up monitoring for patients with asymptomatic lesions is unnecessary unless pain develops at the appropriate spinal level. It is concluded that management of patients with a progressive neurological deficit should include preoperative angiography and embolization, decompressive surgery with the approach determined by the degree of vertebral involvement and site of spinal cord compression, and postoperative radiation therapy in patients following subtotal tumor removal. Operative management and complications are discussed.

The study involved 77 myxopapillary ependymomas of the spinal cord encountered during a 60-year period (1924-1983). This variant of ependymoma was, with few exceptions, limited to the lumbosacral region, particularly the filum terminale. The ma1e:female ratio was 1.7:1, and the mean age at diagnosis was 36.4 years (range, 6-82); a t presentation, 15 (19%) of the patients were in the first two decades of life. The duration of symptoms ranged from 1 month to 30 years; the most frequent complaint was low-back pain, and eight patients had undergone prior "disc surgery." Generally, myelographic block was disclosed. Preoperative cerebrospinal fluid protein levels averaged 2462 mg/dl. M yxopapillary ependymomas are slow-growing tumors that show no significant tendency to histologic dedifferentiation. Despite some variation in cytologic features and the presence of atypia and modest mitotic activity in most cases, the gross characteristics of the tumors appear to be of greater prognostic significance than the histologic features. Tumors that were encapsulated (25%) and amenable to intact, total surgical removal had a recurrence rate of lo%, whereas those that were removed either piecemeal (34%) or subtotally (41%) had recurrence rates of 19%. Overall survival, however, was more closely related to residual disease; total removal of tumor, whether intact (encapsulated) or piecemeal, resulted in longer survival (19 years) than did subtotal resection (14 years). Patients who died (6.5%) did so after a prolonged course marked by multiple recurrences. Radiotherapy may be of particular benefit to patients whose tumors are not amenable to intact total removal. Comer 56:883-893, 1985. PENDYMOMAS are uncommon intracranial lesions, E comprising approximately 5 % to 6% of all brain tumors.'*' In the spinal cord, however, they represent approximately 63% of all parenchymal tumors, although figures have ranged from 30%3-5 to 88%.lV6,' In 1932, Kernohan' divided his large series of spinal ependymo-mas into epithelial, cellular, and myxopapillary types, reflecting the morphologic spectrum of ependymal differentiation. Since that time, it has been repeatedly observed that the papillary pattern predominates among tumors of the filum terminale and conus medullaris.' Most such tumors demonstrate characteristic penvascular and intercellular accumulation of mucin as well as vascular hyalinization. This distinctive variant, the myxopapillary ependymoma, is almost exclusively observed in this location, although occasional examples are encountered at other spinal levels or intra~ranially.'~'~ Although likely to recur locally, myxopapillary ependy-momas primary in the cauda equina region rarely From the Departments of *Pathology and tNeurologic Surgery, Mayo Clinic and Mayo Foundation, Rochester. Minnesota. Address for reprints: Bernd W. Scheithauer, MD, Department of Pathology, Mayo Clinic, Rochester, MN 55905.

The nature of perineurioma, variably termed "localized hypertrophic neuropathy," "intraneural neurofibroma," and "hypertrophic interstitial neuritis" has long been an issue of contention. Most authors consider it a neoplasm, but some a reactive process. Eight clinically and morphologically typical perineuriomas were studied by histologic, immunohistochemical and ultrastructural methods. One perineurioma was subject to tissue culture and cytogenetic study and another to fluorescence in situ hybridization (FISH) analysis. The patients, 3 males and 5 females, ranged in age from 11 to 38 years. All tumors were intraneural, and involved extremities (2 sciatic, 1 median, 1 femoral, 1 peroneal, 1 brachial plexus, 1 ulnar, and 1 radial). Neurologic symptoms, motor in all cases and sensory in 4, were present from 1 month to 7 years (mean 1.2 years). Fusiform, segmental nerve enlargement was clinically apparent in only two patients, but was evident on MRI in five of eight patients. Lesion length ranged from 3.5 to 30 cm, the largest involving the sciatic nerve from the obturator foramen to the knee. One lesion involved two nerve roots, but no association with a phakomatosis was noted. Treatment consisted of biopsy in six cases and resection in two cases. Histologically, pseudo-onion bulbs composed of epithelial membrane antigen-reactive, S-100 protein-negative perineurial cells surrounded myelinated or nonmyelinated nerve fibers. Many were accompanied by their S-100 protein-positive Schwann sheaths. Some whorls lacked a central axon. A single mitosis was noted in one case. The MIB-1 antigen labelling index ranged from 4% to 17%. Staining for p53 antigen in six cases showed no (2 of 6), rare (2 of 6), or scattered (2 of 6) immunoreactive nuclei. Cytogenetic analysis in one case demonstrated a chromosomally abnormal clone. Each of 16 metaphases was abnormal; the tumor cells appeared to be homozygously deficient for the region 22q11.2qter. In another case, 53% of interphase nuclei showed three FISH signals with a chromosome 14/22 probe, thus suggesting either monosomy for the centromere of chromosome 14 or that of chromosome 22.(ABSTRACT TRUNCATED AT 400 WORDS)

One hundred twenty-four patients with degenerative lumbar stenosis underwent decompression with fusion (32 patients) and without fusion (92 patients) during a 30-month period between 1986 and 1988. Patient-reported satisfaction at a mean follow-up period of 5.8 years (range 4.6-6.8 years) revealed a 79% good or fair outcome and a 21% poor outcome (26 patients). Seven patients (6%) developed lumbar instability, three patients (2%) developed new stenosis at an adjacent unoperated level, and three patients (2%) developed a new disc herniation between 2 and 5 years after surgery. Progressive postoperative spondylolisthesis occurred in 31% of patients with normal preoperative alignment (mean 7.8 mm, range 2-20 mm) and in 73% of patients with preoperative subluxation (mean 5.1 mm, range 2-13 mm) in whom fusion was not attained. Radiological progression did not correlate well with patient-reported outcome. The major conclusions from this study are the following: 1) the majority of patients respond well to this surgery, but complication (22%) and late deterioration (10%) rates are not insignificant; 2) radiological instability is common after decompression for degenerative lumbar spinal stenosis, but this correlates poorly with clinical outcome; 3) there are no definitive clinical or radiological factors that preoperatively predict patients at risk for a poor outcome; 4) post-operative radiological instability is more likely to occur when the following criteria are present: preoperative spondy-degenerated L-4 or a markedly degenerated L-3 disc; and when a radical and extensive decompression greater than one level is planned; and 5) the group at greatest risk for a poor outcome consists of those patients with normal preoperative alignment who do not suffer slippage following surgery.

An unusual fibrocalcifying lesion of the neural axis was identified in 14 cases. The radiographic appearance was that of a mass, which in some instances was calcified. The surrounding structures were compressed and the adjacent bone was involved. Histologically, the process was basically a granulomatous one. The granulomas were either nodular or confluent, producing a large mass with peripheral lobular configuration. Epithelioid cells and giant cells bordered the granulomas. Most of the granulomas were composed of fibrochondrocalcifying material. The lesion was particularly dangerous when located in a strategic site, such as the foramen magnum or the base of the skull. Two of the 14 patients with this pseudotumor died, and the other 12 have done well. Complete ablation, marginal or even intralesional, assures control of the lesion. The lesion is probably reactive rather than neoplastic.