Faculty Bibliography

Seven patients with bone or soft tissue sarcomas but without metastatic CNS disease developed a chronic leukoencephalopathy after high-dose (8000-15,000 mg/m2) iv methotrexate (MTX) chemotherapy with leucovorin (LV) rescue. Approximately 12 MTX-LV treatments were administered over a 3-7 month period. None of the patients had cranial irradiation. The syndrome usually began several months after the initiation of chemotherapy with subtle personality changes followed by a progressive dementia, focal seizures, pseudobulbar palsy, spastic quadriparesis, and stupor. Computerized tomographic scans revealed diffuse white matter hypodensity in five patients and atropic changes in five patients. Serum MTX concentrations were elevated in four of six patients prior to several MTX-LV treatments, suggesting that MTX persisted in tissues for a long time. Abnormally high levels of MTX were detected in the cerebrospinal fluid of all four patients several days after an MTX-LV treatment, at a time when their encephalopathy was most severe. Pathologic brain material was obtained from three patients and revealed a spectrum of abnormalities. The syndrome observed in our patients clinically resembles the one described in children with acute lymphatic leukemia who received cranial irradiation and large cumulative amounts of low-dose (12-20 mg/m2) systemic MTX without LV

Intracarotid (i.c.) hyperosmolar mannitol enhances central nervous system (CNS) penetration of intravenous (i.v.) methotrexate (MTX) in normal adult rats. A fivefold augmentation in the CSF:serum and ipsilateral brain:serum MTX concentration ratios was observed 1 hour after drug administration. Intravenous mannitol had no such effect. Rats with meningeal carcinomatosis have a partial defect in blood-brain barrier function, and the CSF:serum MTX concentration ratio was 4.6 times higher in these animals than in normal rats prior to mannitol therapy. Intracarotid hyperosmolar mannitol further augmented the blood-brain barrier permeability to intravenous MTX. Intracarotid mannitol increased the therapeutic effect of MTX, since rats with meningeal carcinomatosis that received i.v. MTX and i.c. mannitol experienced a slight enhancement in survival

The cerebrospinal fluid (CSF) and serum of six patients with histologically verified intracranial germ-cell tumors were assayed serially for the presence of alphafetoprotein (AFP) and the beta subunit of human chorionic gonadotropin (HCG). Two patients had embryonal carcinomas, two had choriocarcinomas, and two had dysgerminomas. The marker profile for a given tumor in either CSF or serum correlated with the histological diagnosis; that is, embryonal carcinoma produced AFP and HCG, choriocarcinoma produced HCG, and dysgerminoma produced no markers. The marker levels in serum and CSF declined with therapy and rose usually prior to the development of overt clinical symptoms if the patient's tumor recurred. A CSF-to-serum gradient of the marker levels was present in three of four patients, and the serum levels were often normal when the CSF values were elevated. Ventricular marker levels were lower than the lumbar levels in two of two patients. The assay of these biological markers is a sensitive indicator of the success of therapy, and the presence of a CSF-to-serum gradient suggests that the major portion of the neoplasm rests within the central nervous system. A histological diagnosis can be inferred without the necessity of surgery in appropriate clinical contexts

Linear drift of X-ray attenuation coefficients must be corrected if quantitative comparisons are to be made between computed tomography (CT) brain scans of the same individual performed at different times. Such a correction is accomplished by comparing the low (cerebrospinal fluid) end of the attenuation coefficient frequency histograms using a percentile--percentile plot. A 'drift correction' permits serial quantitative assessments of the progression or regression of white matter hypodensity, such as occurs in drug induced leukoencephalopathy

An unusual neurological syndrome occurred in 4 of 158 patients treated for osteogenic sarcoma with combination chemotherapy. There was an abrupt onset of focal cerebral deficits approximately ten days after chemotherapy with vincristine and high-dose methotrexate plus citrovorum factor rescue. The syndrome was short lived and always occurred early in the course of treatment. Prolonged neurological deficits remained in 2 patients. When similar chemotherapy was reinstituted in the 4 patients, no further neurological complications ensued. Possible causes include a leukoencephalopathy related to methotrexate or an embolic cerebral vasculopathy related to necrotic tumor microemboli emanating from the lungs

A clinical or subclinical leukoencephalopathy occurs in some children after treatment of acute lymphatic leukemia with prophylactic cranial radiation therapy and parenteral or intrathecal methotrexate. We have observed a similar clinical leukoencephalopathy in patients with bone tumors treated with intravenous high-dose methotrexate and citrovorum factor without cranial irradiation. CT scans of such patients may indicate decreased white matter attenuation, but visual appraisal of this phenomenon is occasionally misleading. A computerized method for analyzing white matter hypodensity by determining the mean attenuation coefficient for one or several contiguous CT slices has therefore been developed. Serial comparisons of this mean attenuation coefficient appear to be more reliable than simple visual appraisal