ABSTRACT
Anaplastic large-cell lymphoma (ALCL) is a T-cell lymphoma composed of large pleomorphic cells that have irregular kidney-shaped nuclei (“hallmark cells”) and are positive for CD30, and in majority of cases, anaplastic lymphoma kinase (ALK) protein. In current WHO classification, ALCL is divided into ALK+ and ALK− type [1]. ALCL involves lymph nodes and extranodal sites, including skin, soft tissues, liver, lung, and bone, and less often central nervous system (CNS) and gastrointestinal tract. ALCL occurs at any age, including children. ALK+ ALCL occurs most commonly in the first three decades of life, is more common in men, presents as aggressive stages III and IV disease with systemic symptoms, has frequently extranodal involvement, and has good response to chemotherapy [2–7]. ALK− ALCL occurs in older patients (peak incidence in 6th decade), with a lower male predominance and less advanced stage, but with frequent involvement of skin, gastrointestinal tract, and liver and lower frequency of bone marrow (BM) involvement [7]. A separate variant of ALK− ALCL in adults occurs in patients with breast implants [8–10].
