Fulminant radiation-induced necrosis after stereotactic radiation therapy to the posterior fossa. Case report and review of the literature.

The problem of radiation-induced necrosis of normal brain surrounding the target area has been a major catalyst for the development of stereotactically focused radiation therapy. According to current opinion, the effects of stereotactic irradiation are confined to the region targeted. The authors present a case in which the administration of a conventional dose of stereotactically focused irradiation for treatment of a pilocytic astrocytoma produced fulminant necrosis that necessitated a combination of intensive surgical and medical management, after which the patient improved over the course of 1 year. Concomitant with his improvement, the initially remarkable findings on magnetic resonance imaging gradually resolved. In this presentation the authors emphasize the need to evaluate alternatives carefully before a decision is made to administer therapeutic irradiation. Furthermore, they explore the roles that target, host, and dosage factors play in hypersensitivity to radiation injury, the detection of these factors before treatment, and the administration of radioprotective agents. With the growing use of stereotactically focused irradiation as a primary treatment modality for a variety of neurosurgical conditions, it is important to be cognizant of its uncommon but potentially lethal side effects. A cooperative multicenter database in which the outcomes and morbidity following stereotactic irradiation are recorded is essential to the detection of relatively uncommon but severe complications such as those observed in this case.

Peripheral neuropathy secondary to docetaxel (Taxotere)

Docetaxel (Taxotere), a semisynthetic analogue of the antitumor agent paclitaxel, inhibits tubulin depolymerization. Paclitaxel produces a peripheral neuropathy. This study delineates clinically and electrophysiologically the characteristics of a peripheral neuropathy due to docetaxel. In 186 patients receiving docetaxel in phase I and phase II protocols, we performed serial neurologic exams. As patients became symptomatic, quantitative sensory testing and nerve conduction studies were done. Twenty-one patients developed mild to moderate sensory neuropathy on taxotere at a wide range of cumulative doses (50 to 750 mg/m2) and dose levels (10 to 115 mg/m2). Ten of these patients also developed weakness of varying degree in proximal and distal extremities. Nine of the 21 patients had received neurotoxic chemotherapy before; 16 were treated with docetaxel at a dose level of 100 to 115 mg/m2. In summary, docetaxel produced a sensorimotor peripheral neuropathy in 11% of our patient population.

MRI of radiation induced spinal cord glioma.

Radiation induced neoplasms of the spinal cord are rare lesions. This report details the MR evaluation of a patient with radiation induced astrocytoma of the cervical cord. The diagnosis of second primary neoplasm should be considered in patients with prior radiation therapy when MRI demonstrates an intramedullary lesion.