Intravascular CNS lymphoma: Successful therapy using high-dose methotrexate-based polychemotherapy

Intravascular lymphoma, also known as intravascular lymphomatosis or angiotropic lymphoma and formerly known as malignant angioendotheliomatosis is a rare neoplastic disorder in which tumour cells are initially confined to the vascular lumen without parenchymal infiltration. While cases of systemic intravascular lymphoma are more frequently encountered, cases of intravascular lymphoma with restricted central nervous system (CNS) involvement (cIVL) are uncommon and only few patients that had been successfully treated have been reported so far [1-4]. We here present a case with a histologically confirmed cIVL that could be successfully treated with a high-dose methotrexate (HD-MTX) and rituximab-based chemotherapy regimen.A 69-year-old male Caucasian patient presented with recurrent transient amnestic aphasia and gait ataxia. Physical examination at the time of referral did not reveal any further pathological findings. B symptoms were absent. Serum LDH levels were twice the upper limit of normal, all other serum chemistry and differential blood count was negative. Cerebrospinal fluid (CSF) analysis revealed a normal cell count, protein levels were within the reference range, no atypical cells were detected. Initial magnetic resonance imaging (MRI) revealed a contrast-enhancing lesion in the pons (Figure？1A) and additional involvement of the left temporomesial area. A stereotactic biopsy was performed and histology revealed a CD20-antigen-expressing intravascular lymphoma with high proliferative activity (Figure？2A, B). Immunohistological evaluation of B-cell differentiation markers showed a BCL-6+ and MUM-1+？status. Subsequent staging (i.e. examination of the chest, abdomen and pelvis by contrast-enhanced computed tomography (CT) scan, bone marrow biopsy, slit lamp examination of the eye, spinal tap) did not reveal any systemic or additional CNS involvement.Chemotherapy according to the Bonn protocol was initiated in combination with rituximab therapy. The Bonn protoc