Artikel
Corticoid mitigated diffuse large B-cell lymphoma of the CNS with plasmacytic / plasmacytoid differentiated marginal zone lymphoma aberrantly expressing BCL6 and MUM1
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Autoren
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Ute Pohl
- Queen's Hospital BHRUT, Cellular Pathology, Romford, United Kingdom
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U.O. Igbokwe
- Queen\'s Hospital BHRUT, Cellular Pathology, Romford, United Kingdom
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C. Hemmaway
- Queen’s Hospital BHRUT, Haematology, Romford, United Kingdom
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J.R. Pollock
- Queen’s Hospital BHRUT, Neurosurgery, Romford, United Kingdom
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W. Klapper
- University of Kiel, Hematopathology, Institute of Pathology, Kiel, Germany; Netzwerk Lymphome und lymphomatoide Läsionen des Nervensystems, (NLLLN), Germany
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W. Brück
- University of Göttingen, Neuropathology, Göttingen, Germany; Netzwerk Lymphome und lymphomatoide Läsionen des Nervensystems, (NLLLN), Germany
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T. Kuhlmann
- University of Münster, Neuropathology, Münster, Germany; Netzwerk Lymphome und lymphomatoide Läsionen des Nervensystems, (NLLLN), Germany
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M. Deckert
- University of Cologne, Neuropathology, Cologne, Germany; Netzwerk Lymphome und lymphomatoide Läsionen des Nervensystems, (NLLLN), Germany
| Veröffentlicht: | 25. August 2015 |
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Gliederung
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Introduction: Primary CNS Lymphoma increasingly affects immunocompetent patients of 50-70 years. More than 95% of cases are diffuse large B-cell lymphoma (DLBCL). Here we present an as yet unreported concomitant occurrence of DLBCL and marginal zone lymphoma in the brain.
Objectives: We aimed to molecularly characterise the two clonal B-cell populations to understand the histogenesis of this complex neoplasm.
Patients and methods: A 72-year-old Caucasian man presented with left hemiparesis for 2 months. CT head revealed a right frontal lobe tumour with features of a glioma.He received low dose dexamethasone (6 mg/d) for two weeks before craniotomy. The sample was analysed by routine histology, immunohistochemistry and various molecular methods. To investigate break point regions of chromosomes 14 and 18 in interphase nuclei, dual colour dual fusion translocation probes (fragments 14q32 and 18q21) were used.Rearrangements in the B cell receptor (IgH/IgL/IgK locus) were assessed by PCR sequence analysis. The patient partially reponded to treatment that included rituximab/methotrexate.
Results: On histology, there is a perivascular and diffuse infiltrate of lymphoid cells throughout the grey and white matter. This mainly consists of small mature lymphocytes without mitoses. Focally, there are blast-like cells with frequent mitoses. Background changes consistent with steroid effect are noted.
The small lymphocytes express CD20, BCL6, MUM1, with C-MYC index up to 40% and ki-67 index <5%. The blast-like cells express CD20, BCL6, MUM1, with C-MYC index up to 80%, and ki-67 index up to 80%. The B-cells are Kappa light chain restricted by ISH. The majority of the tumour cells harbour four distinct signals, corresponding to both IgH and BCL2 alleles. No break points are seen in the BCL6 or IgH gene. EBV RNA is not detected.The small B-cells reveal a clonal rearrangement in the B-cell receptor locus IgK, but not in IgH or IgL.In contrast, the B-cell blasts reveal two clonal rearrangements in the IgK (identical) and the IgH locus, respectively.
Conclusion: The appearances are those of a corticoid mitigated DLBCL with plasmacytic / plasmacytoid differentiated marginal zone lymphoma showing aberrant expression of BCL6/MUM1, suggesting divergent differentiation. Concerning treatment, the tumour should be considered as CNS DLBCL.
