Intraventricular meningiomas of the lateral ventricle occur relatively rarely, but they are often large at the time of detection and present more commonly on the left side. Although the ability to resect these tumors safely has greatly improved over time, standard surgical approaches often traverse cortex close to areas of specific cortical function. Precise cortical mapping of language and sensorimotor cortices can be accomplished noninvasively by using functional magnetic resonance (fMR) imaging. The authors used fMR imaging in planning the cortical incision for resection of a large intraventricular trigone meningioma in the dominant hemisphere of a patient who, postoperatively, suffered no aphasia or hemiparesis. The authors discuss the advantages of mapping cortical function preoperatively with fMR imaging when approaching intraventricular lesions.
William T. Curry Jr., G. Rees Cosgrove, Bradley R. Buchbinder and Robert G. Ojemann
William T. Curry Jr., Garth Rees Cosgrove, Fred H. Hochberg, Jay Loeffler and Nicholas T. Zervas
Object. The Photon Radiosurgery System (PRS) is a miniature x-ray generator that can stereotactically irradiate intracranial tumors by using low-energy photons. Treatment with the PRS typically occurs in conjunction with stereotactic biopsy, thereby providing diagnosis and treatment in one procedure. The authors review the treatment of patients with brain metastases with the aid of the PRS and discuss the indications, advantages, and limitations of this technique.
Methods. Clinical characteristics, treatment parameters, neuroimaging-confirmed outcome, and survival were reviewed in all patients with histologically verified brain metastases who were treated with the PRS at the Massachusetts General Hospital between December 1992 and November 2000. Local control of lesions was defined as either stabilization or diminution in the size of the treated tumor as confirmed by Gd-enhanced magnetic resonance imaging.
Between December 1992 and November 2000, 72 intracranial metastatic lesions in 60 patients were treated with the PRS. Primary tumors included lung (33 patients), melanoma (15 patients), renal cell (five patients), breast (two patients), esophageal (two patients), colon (one patient), and Merkle cell (one patient) cancers, and malignant fibrous histiocytoma (one patient). Supratentorial metastases were distributed throughout the cerebrum, with only one cerebellar metastasis. The lesions ranged in diameter from 6 to 40 mm and were treated with a minimal peripheral dose of 16 Gy (range 10–20 Gy). At the last follow-up examination (median 6 months), local disease control had been achieved in 48 (81%) of 59 tumors. An actuarial analysis demonstrated that the survival rates at 6 and 12 months were 63 and 34%, respectively. Patients with a single brain metastasis survived a mean of 11 months. Complications included four patients with postoperative seizures, three with symptomatic cerebral edema, two with hemorrhagic events, and three with symptomatic radiation necrosis requiring surgery.
Conclusions. Stereotactic interstitial radiosurgery performed using the PRS can obtain local control of cerebral metastases at rates that are comparable to those achieved through open resection and external stereotactic radiosurgery. The major advantage of using the PRS is that effective treatment can be accomplished at the time of stereotactic biopsy.
Scott R. Plotkin, Caroline C. O'Donnell, William T. Curry Jr., Catherine M. Bove, Mia MacCollin and Fabio P. Nunes
The aim of this paper was to define the clinical characteristics of spinal ependymomas associated with neurofibromatosis Type 2 (NF2).
The authors retrospectively reviewed the clinical records of patients with NF2 who had imaging findings consistent with ependymomas and were seen at Massachusetts General Hospital between 1994 and 2007. Clinical characteristics of these patients were obtained from hospital records, imaging studies, surgical reports, and pathology reports. Mutational analysis of the NF2 gene was performed in 37 of 44 unrelated patients.
Fifty-five patients met inclusion criteria for the study. The median age at diagnosis of NF2 was 21 years; the median time after diagnosis until identification of ependymomas was 5 years. Multiple ependymomas were present in 58% of patients. The most common site of involvement was the cervical cord or cervicomedullary junction (86% of imaging studies), followed by the thoracic and lumbar cords (62% and 8%, respectively). The majority of patients had no symptoms related to their tumors (42 patients [76%]). After a median follow-up of 50 months, surgery was performed in 11 patients (20%) for symptomatic progression (indications for surgery). Mutational analysis of the NF2 gene detected alterations in 28 (76%) of 37 unrelated patients, with nonsense and frameshift mutations accounting for 64% of detected mutations. The high rate of truncating mutations may help explain the high tumor burden in these patients.
Neurofibromatosis Type 2–related ependymomas exhibit an indolent growth pattern with tumor progression limited to a minority of patients. The authors believe that surveillance is reasonable for asymptomatic ependymomas, including those with cystic areas that expand the cord. For symptomatic tumors, resection may be warranted depending on age, overall clinical status, and ease of resectability.