[CR-02] ALK-positive large B-cell lymphoma
Department of Pathology, Facolty of Medicine, Khon Kaen University, Khon Kaen, Thailand
ALK-positive large B-cell lymphoma (ALK-positive LBCL) is a rare type of lymphoma. Because of the overlap of morphological and immunophenotypic features with other haematologic and non-haematologic neoplasms, diagnosing ALK-positive LBCL can be challenging. The lymph nodes showed a marked diffuse infiltrate of monomorphic large immunoblast-like cells with round pale nuclei containing a large central nucleolus and abundant amphophilic cytoplasm. Lymphoma cells were strongly positive for the ALK protein. The neoplastic cells strongly expressed EMA and plasma cell markers with positive cytoplasmic immunoglobolin and light chain restriction. In most cases, they were negative or only sometimes positive for B-cell lineage–associated antigens and CD30. In conclusion, a diagnosis of ALK-positive LBCL is based on a combination of histomorphology and immunohistochemical markers, particolarly ALK protein.
Keywords: anaplastic lymphoma kinase; immunohistochemistry; large B-cell lymphoma