Getting the diagnosis right in NHL: role of immunohistochemistry and molecular diagnostic testing

Challenges in diagnosing lymphoid neoplasms include their complex heterogeneity and the fact that approximately 40 or more diseases exist. Immunophenotyping and molecular diagnostics have made important contributions to precise and accurate diagnoses. Strong interactions with clinical colleagues and meticulous attention at the microscope by expert hematopathologists are important in making a correct diagnosis. Awareness of the literature and interactions with research colleagues, including clinical, basic, and translational scientists, have expanded understanding of these complex diseases, providing prognostic information that can ultimately assist in appropriate clinical management of patients or development of new targeted therapies. This article reviews recent published immunophenotypic diagnostic and biomarker studies, discusses molecular diagnostic expression profiling studies of the more common entities encountered in daily clinical practice, and references published summaries from the combined Society of Hematopathology and European Association for Haematopathology Workshops. A precise lymphoma diagnosis therefore involves integration of clinical information, morphologic architectural and cytologic patterns, immunohistochemistry, cytogenetics, and molecular biology, to ultimately allow identification of specific diseases, thereby implying prognostic significance and potential therapeutic targets.