RESUMO
BACKGROUND: Here we describe a case of PCNSL which was located peripherally as a single lesion and showed no evidence of pathological findings of lymphoma at the first biopsy. CASE DESCRIPTION: A 56-year-old man was admitted to the hospital with a talking disorder and attention deficit. The neurological examination was normal. There was a left temporoparietal, 24 x 20 mm. enhanced lesion on MRI. The patient underwent a craniotomy and the lesion was excised totally. The pathological examination revealed glial tissue which showed reactive astrocyte proliferations. A month later, an MRI was performed and a recurrent tumor was seen near the first lesion's location. The second operation was performed via the same craniotomy, the tumor was excised totally and the second pathological examination revealed diffuse large-cell, B-lymphoma. There were no pathological findings on abdominal, thoracic and bone marrow investigations. CONCLUSION: PCNSL may show various biological behaviors. Using steroids before the biopsy may lead to diagnostic and therapeutic failure.