The interface of Hodgkin's disease and anaplastic large cell lymphoma.

We reviewed 18 cases in which morphology was intermediate between Hodgkin's disease (HD) and anaplastic large cell lymphoma (ALCL). Eight cases exhibited the usual CD30+, CD15+/-, null cell phenotype of classic HD but were rich in neoplastic cells with sinusoidal infiltrating pattern. In this group, there was no expression of antigens (EMA, BNH9, CBF78) associated with ALCL, and only two were positive for Epstein-Barr virus (EBV). Ten EBV negative cases fit the description of HD like ALCL by variable expression of antigens unassociated with HD. EMA was clearly and strongly expressed in all ten, whereas antigens recognized by BNH9 and CBF78 were expressed in four and three cases, respectively. Focal expression of CD45 and CD43 was observed in half of these cases. In only one case was the t(2.5) translocation detected with the new monoclonal antibody, ALK1. Therefore, the expression of EMA, BNH9 and CBF78, often in concert without CD15 and without the specific translocation, appears currently to be the most probable phenotype and genotype of HD like ALCL. There was a tendency for aggressive behaviour of the disease considered HD like ALCL. Whether such patients will benefit from a therapeutic strategy that takes into account both phenotype and genotype remains to be discovered.