Morphologic Features of XXXX -negative Anaplastic Large Cell Lymphomas With @entity17968 Rearrangements.

@entity7041 @entity1711 @entity1710 @entity2108 @entity17968
Systemic @entity2108 ( @entity2108 ) are classified into @entity7041 -positive and @entity7041 -negative types. We recently reported that @entity7041 -negative @entity2108 are genetically heterogenous. The largest subset, representing 30% of cases, had rearrangements of the @entity17968 locus. These cases had favorable outcomes similar to @entity7041 -positive ALCL, and superior to other @entity7041 -negative @entity2108 . Here, we examined the morphologic features of these cases in more detail. First, we conducted blinded review of @entity1710 and @entity1711 slides of 108 @entity2108 from our previous study, scoring cases for the presence of 3 histologic patterns and 5 cell types. Cases then were unblinded and re-reviewed to understand these features further. @entity17968 -rearranged @entity2108 were more likely than other @entity7041 -negative @entity2108 to have so-called doughnut cells (23% vs. 5%; P=0.039), less likely to have pleomorphic cells (23% vs. 49%; P=0.042), and nearly always (95%) had areas with sheet-like growth (common pattern). To examine the reproducibility of these findings, we conducted blinded review of @entity1710 and @entity1711 slides of 46 additional @entity7041 -negative @entity2108 using a 0 to 3 scoring system to predict likelihood of @entity17968 rearrangement, the results of which correlated strongly with subsequent findings by fluorescence in situ hybridization (P<0.0001). Although all @entity2108 share certain morphologic features, @entity2108 with @entity17968 rearrangements show significant differences from other @entity7041 -negative @entity2108 , typically showing sheets of hallmark cells with doughnut cells and few large pleomorphic cells. These morphologic findings and our previous outcome data suggest that @entity7041 -positive @entity2108 and @entity17968 -rearranged @entity2108 represent prototypical @entity2108 , whereas @entity2108 lacking rearrangements of both @entity17968 and @entity7041 require further study.
