OBJECTIVE: To study clinicopathologic and genetic features of anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma (LBCL). METHODS: Light microscopy, EliVision immunohistocheimical method and fluorescence in-situ hybridization were used to evaluate three ALK + LBCL cases recently diagnosed accompanied with a literature review. RESULTS: All three cases were male adult patients (mean age = 36.3 years) with nodal involvement by lymphoma. Histologic evaluation revealed a diffuse effacement of the nodal architecture by the infiltration of tumor cells. Sinusoidal infiltration was seen. The neoplastic cells were large and exhibited the immunoblastic/plasmablastic morphology. By immunohistochemistry, all the cases showed a cytoplasmic granular staining of ALK. They were positive for CD45, CD138, and epithelial membrane antigen (EMA), but were negative for CD3, CD20, CD79a and CD30. Fluorescence in situ hybridization (FISH) demonstrated the presence of ALK gene translocation in all of the cases. CONCLUSIONS: ALK + LBCL represents a distinct variant of diffuse large B-cell lymphoma, usually involving lymph node of middle-aged men. The tumor has a immunoblastic/plasmablastic morphology along with a distinct immunophenotypic profile and ALK gene rearrangement.
OBJECTIVE: To study clinicopathologic and genetic features of anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma (LBCL). METHODS: Light microscopy, EliVision immunohistocheimical method and fluorescence in-situ hybridization were used to evaluate three ALK + LBCL cases recently diagnosed accompanied with a literature review. RESULTS: All three cases were male adult patients (mean age = 36.3 years) with nodal involvement by lymphoma. Histologic evaluation revealed a diffuse effacement of the nodal architecture by the infiltration of tumor cells. Sinusoidal infiltration was seen. The neoplastic cells were large and exhibited the immunoblastic/plasmablastic morphology. By immunohistochemistry, all the cases showed a cytoplasmic granular staining of ALK. They were positive for CD45, CD138, and epithelial membrane antigen (EMA), but were negative for CD3, CD20, CD79a and CD30. Fluorescence in situ hybridization (FISH) demonstrated the presence of ALK gene translocation in all of the cases. CONCLUSIONS:ALK + LBCL represents a distinct variant of diffuse large B-cell lymphoma, usually involving lymph node of middle-aged men. The tumor has a immunoblastic/plasmablastic morphology along with a distinct immunophenotypic profile and ALK gene rearrangement.