Anaplastic large cell lymphoma presenting with a leukemoid reaction in infants

Abstract

Anaplastic large cell lymphoma, ALK-(+), is an aggressive type of T-cell lymphoma characterized by large cells with bizarre morphologic features, prominent sinusoidal invasion and expression of CD30 and ALK antigens. The majority of patients present with advanced clinical stage have nodal and extranodal involvements and complain of B-symptoms. The disease is most frequent in the first three decades of life with a median age of 35 years. The development of ALCL-ALK(+) in infants is very rare, with only very few case reports in the literature. We report two cases of male infants who presented with fever and a progressive leukemoid reaction. The leukocytosis was mainly neutrophilic and monocytic without lymphoma cells, and in one case the neutrophils were severely toxic. Extensive workup for infections and acute leukemia did not reveal any cause. The diagnosis of ALCL-ALK(+) was established after demonstration of enlarged neck and abdominal lymph nodes in the first and second patients, respectively, when they underwent histologic evaluation. Although rare, our cases show that ALCL-ALK(+) is still a likely cause of a leukemoid reaction in infants in a manner similar to infectious diseases, and a survey of lymph nodes enlargement would prevent delay in diagnosis.