Contributed by T. Kuhlmann1,2, S. Vogelgesang3, B. Gunawan4, J. Scheunemann5, A. Wolters5, W. Brück1
Institute of Neuropathology, University Hospital Münster, Münster, Germany,
2Department of Neuropathology, University Medical Centre, Göttingen, Germany,
3Department of Neuropathology, University of Greifswald, Greifswald, Germany,
4Department of Gastroenteropathology,
5University Medical Centre, Göttingen, Germany, Department of Neurology, University of Rostock, Rostock, Germany.
A forty-six year old female patient presented with a five month history of numbness in the toes of the right foot accompanied by numbness in the right arm since two months. She developed a paresis of the right leg and focal seizures. The MRI revealed a contrast enhancing lesion in the left occipital and parietal lobe. Three years ago a multiple myeloma (MM) (IgG, stage IIIA) was diagnosed and treated with autologous stem cell transplantation. One year later a relapse with fracture of the fourth lumbar vertebral body occurred, treated by radiation. A stereotactic biopsy of the CNS lesion was performed.
The lesion was diffusely infiltrated by lympho-mononuclear cells. Infiltrates were accentuated around small and medium-sized vessels and observed within the lesion as well as in the adjacent white matter. No fibrinoid vessel necrosis or thrombotic occlusions of vessels were observed. The infiltrates consisted of numerous macrophages, plasma cells and lymphocytes as identified by morphology and immunohistochemistry
Only single CD20-positive B cells were detected in the perivascular infiltrates, whereas numerous CD79a-positve cells were found in the parenchyma (Fig 1). The CD138-positive plasma cells had pleomorphic nuclei; and some were multi-nucleated (Fig 2, insert). Lambda as well as kappa chain-expressing plasma cells were observed. Few mitotic and apoptotic cells were observed.
Within the lesion, single cells with large pale nuclei were seen which were negative for the astrocytic and oligodendroglial makers GFAP and Nogo-A (3). Myelin stainings, such as LFB-PAS (Fig 3) or immunohistochemistry for MBP revealed an ill-defined demyelinating lesion with a relative preservation of axons and oligodendrocytes. Numerous foamy macrophages were diffusely distributed throughout the lesion containing PAS-positive myelin degradation products within their cytoplasm. Reactive GFAP-positive astrocytes were found within the lesion and the adjacent white matter. About 10 % of the infiltrating cells were proliferating as shown by immunohistochemistry with the proliferation marker Ki67. Proliferating plasma cells were also detected (Fig 4).