ALK pos Large B-cell Lymphoma
ALK-positive large B-cell lymphoma (ALK+ LBCL) is a highly aggressive subtype of large B-cell lymphoma that expresses anaplastic lymphoma kinase (ALK) gene. It occurs in young patients (median age 36 years; one-third cases occur in children) with a male:female ratio of 3:1. There is no association with immunosuppression. Most patients present with advanced nodal disease and succumb to the tumor within a year of diagnosis. This image shows ALK+ LBCL in a cervical lymph node biopsy from a 38 y/o male who presented with a large neck mass. The nodal architecture was effaced by cohesive sheets of immunoblastic cells with epithelioid appearance. The tumor cells have large vesicular nucleus, single central prominent nucleolus and abundant basophilic cytoplasm. The immunohistochemical profile was as follows: POSITIVE - ALK (cytoplasmic granular pattern), CD138, kappa light chains, CD4, and CD45. NEGATIVE - CD30, lambda light chains, CD20, EMA, cytokeratin AE1/AE3, S-100, and Melan-A.