Primary leptomeningeal B-cell lymphoma.

Abstract

A 47-year-old man presented with a 6-week history of left facial paraesthesia, diplopia and progressive ataxia with altered sensation in both feet. Contrast magnetic resonance imaging (MRI) of brain and spinal cord demonstrated abnormal thickening and leptomeningeal enhancement of all visible cranial nerves, most striking in cranial nerves III (top left) and V (top right). Further leptomeningeal enhancement was evident in the anterior pons, brain stem and cauda equina but no parenchymal brain or spinal cord lesions were present. Whole body positron emission tomography showed no evidence of disease elsewhere. Cerebrospinal fluid (CSF) examination showed total protein 5.25 g/l [normal range (NR) 0.1–0.5], glucose <0.3 mmol/l (NR 2.5–4.5) and elevated white cell count at 165/mm3 (NR < 10), comprising 80% lymphoid cells and 20% neutrophils. A CSF cytospin demonstrated a population of large, pleomorphic cells with prominent nucleoli on a background of small, mature T cells (bottom left). The large cells were strongly positive for CD20 and CD79a (bottom right) but negative for CD10 and terminal deoxynucleotidyl transferase. A diagnosis of primary leptomeningeal B-cell lymphoma was made. The patient commenced MATRIX (methotrexate, cytarabine, rituximab and thiotepa) immunochemotherapy with rapid improvement in symptomatology and resolution of the cranial nerve thickening on MRI. He completed 4 cycles of MATRIX followed by a thiotepa-conditioned autologous stem cell transplant and remains in complete remission 14 months after presentation.