Linfoma Anaplásico de Grandes Células primário do SNC, ALK-negativo: Relato de Caso

The Anaplastic Large Cell Lymphoma (ALCL) is a rare subtype of non-Hodgkin’s lymphoma (NHL). Citogenetically, it has a strong expression of the activation marker CD30 and around 65-80% of ALCL shows the expression of anaplastic lymphoma kinase (ALK).  They are classified in ALK-positive ALCL when express the kinase, relating to a better therapy response and greater overall sur-vival, or in ALK-negative ALCL in case of non-expression. The incidence of CNS ALCL is highly rare, with less of 1% of cases corresponding to primary CNS anaplastic large cell lymphoma. In the following report, we present a rather unusual case of a primary CNS ALCL, ALK-negative, in a young fe-male patient, which has epidemiological characteristics opposite to the ones described in the literature for this kind of presentation. The first differential diagnostic hypothesis was a high-grade primary CNS glial neoplasia. However, the immunohistochemical defined it as ALK-negative ALCL, according to the cytogenetic expression pattern (positives CD30 and CD3, high cell proliferation rate and negative for ALK-1). The therapy of choice was 4 cycles of chemotherapy with methotrexate and cytarabine, associated with radiotherapy.