Transient spontaneous regression of lesions was identified in four patients with intracerebral lymphoma. This finding, which may be related to cyclic changes in biological tumor activity as well as infarction and/or hemorrhage within the neoplasm, is not a good prognostic sign. Furthermore, when initial neuroradiologic studies suggest a diagnosis of lymphoma, subsequent spontaneous resolution of lesions should not be mistaken for a reliable sign of a benign, self-limiting disease. The diagnosis of this malignant neoplasm, despite regression of lesions, should be aggressively pursued early in the patient's clinical course when therapy would be most beneficial.
