Richter's syndrome in the brain first manifested as an ischaemic stroke.

Isolated central nervous system involvement in Richter's syndrome (RS) is extremely rare and only 6 such cases have been described, so far. We report a 60-year-old woman with B-cell chronic lymphocytic leukemia (B-CLL) heavily pretreated with cladribine based regimens and rituximab in whom RS in the brain was first manifested as a stroke. Initial cranial computed tomography (CT) revealed a hypodense area in the right parietal lobe showing no contrast enhancement. The follow-up CT done after 2 months showed an irregular, slightly hyperdense tumor surrounded by oedema with mass effect and midline shift. However, cerebrospinal fluid (CSF) examinations revealed no pathological changes. Neurosurgical operation was performed and the diagnosis of diffuse large B-cell lymphoma (DLBCL) has been established on the basis of histological and immunological investigation of the tumor. The pattern of immunoglobulin heavy chain (IgH) gene rearrangement in the patients' bone marrow aspirate and brain tumor was identical and suggested that both tumors originated from the same B-cell progenitors. The patient was then treated with brain irradiation (2000 cGy) and complete remission as assessed by MRI was achieved. Significant neurological improvement was observed and no clinical progression was stated 3 months after radiotherapy.