Ghost and mimicry tumors - primary CNS lymphoma

In recent years, the frequency of primary cerebral lymphoma (PCNSL) has inc reased, even among immunocompetent patients. In order to treat the disease optimally, early diagnosis is important. We present three patients with aty pical courses of this disease and stress the importance of PCNSL in the dif ferential diagnosis for optimal treatment. in a 75-year-old man,a space-occ upying, radiopaque, enhancing CNS lesion disappeared completely after biops y and short steroid therapy. One year later,the tumor recurred on the other side and again regressed after steroid therapy. The first biopsy showed si gns of a papillary tumor, so a choroid plexus papilloma was suspected initi ally. A 57-year-old woman developed progressive bilateral hearing dysfuncti on. Lymphocytic pleocytosis led to a primary diagnosis of chronic lymphocyt ic meningitis. During the further course of disease, the patient developed multiple space-occupying cerebral lesions. Stereotactic biopsy revealed PCN SL. Despite combined chemo- and radiotherapy,a relapse occurred. A 49-year- old woman rapidly developed memory and concentration disturbances. Computed tomography revealed diffuse edema in both hemispheres and MRI detected sev ere, diffuse, white matter lesions. The CSF revealed lymphocytic pleocytosi s including plasma cells. Herpes encephalitis and, after lack of clinical i mprovement and progression of the MRI changes, acute disseminated encephalo myelitis (ADEM) were suspected. Corticosteroid treatment was initiated. Aft er enormous clinical improvement, a clinical relapse occurred and MRI detec ted bitemporal and singular space-occupying lesions in the corpus callosum and hypothalamus. Finally, open biopsy showed PCNSL. However,on examination of the treatment history of patient 1, the initial d iagnosis must be revised; a PCNSL seems most probable. The phenomenon of tu mor remission under steroid administration is rare. In patients 2 and 3, at ypical clinical signs and symptoms delayed diagnosis of PCNSL. This tumor c an mimic diverse neurological diseases and remit following corticosteroid t reatment alone. in unclear cerebral disease,biopsy should be performed earl y for exact diagnosis and optimal treatment.