Anaplastic lymphoma kinase–positive large B-cell lymphoma: a case report with particular immunophenotypic features

Summary Anaplastic lymphoma kinase–positive large B-cell lymphoma is a rare and aggressive B-cell lymphoma mostly associated with t(2:17) involving the clathrin gene at 17q23 and the anaplastic lymphoma kinase gene at 2p23. The characteristic immunophenotype includes a granular cytoplasmic anaplastic lymphoma kinase expression, CD20 negativity and the presence of plasma cell markers (CD138, VS38c, and CD38). We report a case with aberrant immunophenotype (CD138−, VS38c−, CD38+/−) and discuss the utility of other immunohistochemical markers in establishing a terminal B-cell differentiation.