Ligamentum flavum cysts causing incapacitating lumbar spinal stenosis.

BACKGROUND: Cysts of the ligamentum flavum are rare and unusual causes of spinal compression. METHODS: We report our experience of four cases of ligamentum flavum cysts occurring in the lumbar spine and discuss some of the possible etiologies and pathophysiologic mechanisms according to the available literature. CONCLUSION: This entity is clearly different from the synovial facet-joints or ganglion cysts.

Brain metastases in patients with ovarian carcinoma: prognostic factors and outcome.

Between January 1975 and April 2001, 8,225 patients with ovarian cancer were seen at The University of Texas M.D. Anderson Cancer Center. Brain metastases developed in 72 of these patients (0.9%). The medical records of these patients were reviewed to assess the incidence of these metastases and their correlates of survival, as well as to describe the various treatment modalities used against them and their respective outcomes. The mean age of patients at the time of brain metastasis diagnosis was 53.7 years. The median interval between the diagnosis of the primary cancer and brain metastasis was 1.84 years. Neurological deficit, headache, and seizure were the most common symptoms. The brain was the only site of metastasis in 43% of patients. Multiple metastases were seen in 65% of them, although this may be a slight underestimate, as brain metastases in 17% of patients were evaluated prior to the magnetic resonance imaging era. The median survival time after the diagnosis of brain metastases was 6.27 months (95% CI, 4.48-8.06 months). The combination of surgical resection and whole-brain radiation therapy (WBRT) resulted in a longer survival time (median, 23.07 months) than did WBRT alone (median, 5.33 months) or surgery alone (median, 6.90 months) (p < 0.01 in both instances, multivariate Cox proportional hazards model analysis). The prognosis for patients with brain metastases from ovarian cancer appears to be poor. The existence of systemic dissemination at the time of brain metastasis was associated with a worse survival trend. The only significant predictor of survival in our series was the treatment modality. In particular, the resection of brain metastasis from ovarian cancer followed by WBRT appeared to be superior to resection alone or WBRT alone.

Spinal cord ependymoma: radical surgical resection and outcome.

OBJECTIVE: Several authors have noted increased neurological deficits and worsening dysesthesia in the postoperative period in patients with spinal cord ependymoma. We describe the neurological progression and pain evolution of these patients over the 1-year period after surgery. In addition, our favored method of en bloc tumor resection is illustrated, and the rate of complications, recurrence, and survival in this group of patients is addressed. METHODS: We operated on 26 patients (12 male and 14 female) with low-grade spinal cord ependymomas between 1975 and 2001. The median age at diagnosis was 42 years. Tumors extended into the cervical cord in 13 patients, the thoracic cord in 7 patients, and the conus medullaris in 6 patients. Eleven patients had previous surgery and/or radiation therapy. RESULTS: We achieved a gross total resection in 88% of patients, whereas 8% had a subtotal resection and 4% had a biopsy. Only 1 patient developed a recurrence over a mean follow-up period of 31 months. CONCLUSION: We conclude that radical surgical resection of spinal cord ependymomas can be safely achieved in the majority of patients. A trend toward neurological improvement from a postoperative deficit can be expected between 1 and 3 months after surgery and continues up to 1 year. Postoperative dysesthesias begin to improve within 1 month of surgery and are significantly better by 1 year after surgery. The best predictor of outcome is the preoperative neurological status.

Aberrant G protein signaling in nervous system tumors.

OBJECT: Guanosine triphosphate (GTP)-binding proteins, also known as G proteins, play important roles in the regulation of cell growth and differentiation by transmitting intracellular signals from cell surface receptors. In this paper, the authors review G protein signaling in general and its aberrations in four human nervous system tumors. METHODS: In the nervous system, four tumor types have been associated with aberrant G protein signaling. The first tumor type includes astrocytomas, which have increased levels of the activated form of the small G protein, p21-ras, without primary oncogenic p21-ras mutations. The likely source for increased p21-ras activity in sporadically occurring astrocytomas is overexpressed or constitutively activated growth factor receptors, whereas in neurofibromatosis Type 1 (NF1)-associated astrocytomas, the source is a loss of expression of neurofibromin, a major inactivator of p21-ras (ras-GTPase activating protein [GAP]). The second type of tumor associated with aberrant G protein signaling includes sporadic and NF1-associated neurofibromas and malignant peripheral nerve sheath tumors, which also have increased p21-ras activity due to a loss of neurofibromin expression. The third tumor type includes subependymal giant cell astrocytomas as part of the tuberous sclerosis complex (TSC). These tumors display a loss of tuberin expression due to germline mutations in the TSC2 gene. Tuberin functions as an inactivator of the small G protein rap1B (rap1-GAP) and, hence, loss of its expression could lead to increased rap1B activity. In addition to TSC-associated tumors, the authors demonstrate that the majority of sporadically occurring astrocytomas display either loss of tuberin or overexpression of rap1B. This suggests that increased rap1B activity, which can augment p21-ras-mediated signals, also contributes to G protein-mediated aberrant signaling in sporadically occurring astrocytomas. The fourth tumor type includes a significant subset of pituitary adenomas that show constitutive activation of the G alpha subunit of the large heterotrimeric G s protein, which is involved in hormone receptor signaling. The net result of this aberrant activation is increased cyclic adenosine monophosphate and mitogenic tumor-promoting signals. CONCLUSIONS: The authors' review of G protein signaling and aberrations in this process is made with the long-term view that increased understanding of relevant signaling pathways will eventually lead to novel biological targeted therapies against these tumors.

Sacrococcygeal ganglioneuroma.

Ganglioneuromas are benign slow-growing masses that can be treated with complete surgical extirpation without any adjuvant therapy. Such lesions involving the sacrococcygeal region are exceedingly rare. The authors present the case of a 70-year-old woman with a sacrococcygeal ganglioneuroma treated by total en bloc resection. This patient also had a previous coccygeal fracture. To the authors' knowledge, there are no other reports of ganglioneuroma in association with a history of trauma.

Misdiagnosis of olfactory neuroblastoma.

OBJECT: Olfactory neuroblastoma (ON) is a rare neoplasm arising from the olfactory epithelium and found in the upper nasal cavity. The authors studied the frequency with which ON is misdiagnosed with other tumors of the paranasal sinuses such as neuroendocrine carcinoma (NEC), pituitary adenoma, melanoma, lymphoma, and sinonasal undifferentiated carcinoma (SNUC). Based on the belief that misdiagnosis commonly occurs, they emphasized the importance of establishing the correct diagnosis, because the treatment regimens and prognosis of these tumor types are often significantly different. METHODS: Twelve consecutive patients in whom ON was diagnosed were referred to the Department of Neurosurgery at the M. D. Anderson Cancer Center between January 1998 and March 2000. Demographic data were collected, physical findings and mode of treatments were documented, and neuroimaging studies were assessed. Pathologists at the authors' institute reviewed the histological specimens. Only in two of 12 patients was the diagnosis of ON confirmed. Lesions in 10 patients were misdiagnosed; there were two cases of melanoma, three cases of NEC, three cases of pituitary adenoma, and two cases of SNUC. Eight of 10 patients in whom lesions were misdiagnosed required significant alteration in the initially proposed treatment plan. CONCLUSIONS: Neurosurgeons should be acutely aware of the variety of neoplasms that occur in the paranasal region. The correct diagnosis should be ensured before initiating treatment to provide the optimum therapy and spare the patients from needless and potentially toxic treatment.