Computer assisted tomography in primary malignant lymphomas of the brain.

Computer assisted tomography (CAT) data from 10 patients with histologically verified primary malignant lymphomas of the brain are reported. Studies both prior to and after contrast medium administration were done on nine patients. In all these patients, tumor nodules presented with slightly increased density in the precontrast scan and considerable contrast enhancement. The appearance of malignant lymphomas in the CAT scan may be similar to that of meningiomas. Pituitary adenoma, medulloblastoma, and metastasis of malignant melanoma may not be ruled out in a particular case from the CAT picture alone. Blurred margin of the tumor after contrast enhancement was found in half the patients. Diffusely growing malignant lymphomas produce low density areas in the CAT scan without contrast medium uptake.