Classic mantle cell lymphoma with aberrant immunohistochemical expression of Fc receptor-like 4/immunoglobulin superfamily receptor translocation-associated 1

The Fc receptor-like 4 (FcRL4)/immunoglobulin superfamily receptor translocation-associated 1 (IRTA1) immunohistochemical marker has emerged in recent literature as a highly specific—albeit moderately sensitive—marker for marginal zone lymphoma with near consistent negativity reported in mantle cell lymphoma (MCL) cohorts. We report a MCL patient with classic clinical, morphologic, immunophenotypic and genetic findings, but having aberrant FcRL4/IRTA1 co-expression. The aberrant expression and its possible favourable prognostic impact in MCL are discussed.