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Mann, 46 J. Exzision eines stark vergrösserten Lymphknotes vom
Kieferwinkel, schmerzfrei
- Diffuser, monotoner Zellrasen aus mittelgrossen Zellen, die in einem
Netzwerk von Kapillaren liegen, ohne kohärente Stränge zu
bilden
- Kerne rund oder ovalär, mässig irreguläre Kontur.
Feines bis grobfleckiges Chromatin, 2 - 5 Nukleoli
- Zytoplasma mittelbreit, ampho- bis basophil
- Mitosen häufig
- Einzel- oder Gruppennekrosen mit Phagozytose der Zell- und vor allem
der Kerntrümmer: "Kerntrümmer-Makrophagen"
geben auf dem Hintergrund des monotonen Zellrasens das Bild des "Sternhimmels"
Aetiologie:
Afrikanisches Burkitt-Lymphom: Assoziation mit EBV und Malaria
Besonderheiten:
Bevorzugt extranodaler Sitz: Kiefer, Ovar, Abdomen
Das Burkitt-Lymphom ist ein sogenanntes "High grade Lymphom"
46-year-old male underwent excision of an enlarged, indolent lymph node at the jaw.
- The lymph node architecture is destroyed by a monotonous population of loosely arranged intermediate-sized cells (between small lymphocytes and immunoblasts) in a capillary network.
- The cells display round to oval somewhat irregular nuclei with a fine to coarse chromatin and 2-5 prominent nucleoli.
- A moderate amount of weakly basophilic to amphophilic cytoplasm is observed.
- The high mitotic rate is characteristic of this tumor.
- Death of single or groups of cells leads to the concomitant presence of tissue macrophages containing cellular debris (Kerntrümmer-Makrophagen).
At lower magnification, the so-called “starry sky” pattern can be appreciated which is created by the lightly stained macrophages surrounded by clear spaces.
Etiology:
Three distinct clinical forms of Burkitt lymphoma are distinguished.
1) Endemic Burkitt lymphoma: Burkitt lymphoma is endemic especially in malarious parts of Africa. Typically, tumor cells in virtually all patients harbor the EBV genome.
2) Sporadic Burkitt lymphoma: In the US, Burkitt lymphoma accounts for less than 1% of non-Hodgkin lymphomas in adults, but for about 30% of non-Hodgkin lymphomas in children.
3) Immunodeficiency-associated Burkitt lymphoma: Burkitt Lymphoma accounts for about 20% of all lymphomas in patients with AIDS. It is rarely seen in the setting of other immunodeficiencies. Only 50% of HIV-associated Burkitt lymphomas are positive for EBV.
Localization:
Extranodal sites are frequently affected (ovaries, bone marrow, GI-tract).
Cytogenetic abnormality:
Translocation of the MYC locus on chromosome 8 to the IgH gene on chromosome 14.
Burkitt lymphoma is a high-grade lymphoma.