Sinusoidal CD30-positive large B-cell lymphoma: A morphologic mimic of anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL) has been recognized recently as a dis tinct clinicopathologic entity, restricted to a subset of CD30-positive dif fuse large cell lymphomas of T/null lineage. Some of the characteristic fea tures of ALCL, such as CD30 antigen expression and the presence of large pl eomorphic lymphoid cells infiltrating lymph node sinuses, can be found rare ly in diffuse large B-cell lymphomas. We collected 11 such cases, and their clinical, morphologic, and immunophenotypic features are reviewed. The age of the patients ranged from 36 to 82 years (mean, 63.2 years) with a male to female ratio of 1:1,2, All neoplasms were nodal with a sinusoidal infilt rative pattern, although four neoplasms also had foci of confluent growth. Eight tumors were composed predominantly of large pleomorphic cells with oc casional Reed-Sternberg-like cells. The other three tumors had a higher pro portion of large monomorphic lymphoid cells. Necrosis and admired granulocy tes were other common features. Immunophenotypically, all cases were positi ve for CD30 and CD20 or CD79a. All eight cases examined for anaplastic lymp homa kinase-1 immunoreactivity were negative. In situ hybridization for Eps tein-Barr virus RNA was performed in eight cases; two were positive. Exclud ing one consultation case with no available clinical follow-up data, six pa tients died of the disease within 3 years and one had disease relapse withi n 1 year. We conclude that an unusual variant of diffuse large B-cell lymph oma can closely mimic ALCL, However, these neoplasms can be distinguished f rom ALCL by virtue of their B-lineage and lack of anaplastic lymphoma kinas e-1 expression, Evidence of Epstein-Barr virus infection can be found in a small subset of these neoplasms.