Ancillary Testing in Lymphoma Diagnosis and the Challenges of Small Biopsies

Course overview

Short description: Although the diagnosis and classification of lymphomas is highly dependent of morphology, some degree of ancillary testing is necessary in almost every case. Immunophenotyping is typically performed to assign or confirm lineage as well as to demonstrate the expected immunophenotype of the diagnosis. In some cases, an immunostain can serve as a surrogate marker for a recurrent genetic abnormality. Cytogenetic and genetic testing can also contribute to lymphoma diagnosis, and FISH testing in particular can identify specific entities and provide prognostic information. Genomic studies such as NGS do not yet play a significant role in lymphoma diagnosis, but a future increasing role is likely. This presentation will discuss the role of ancillary testing in lymphoma diagnosis and highlight a few entities where additional testing adds important information. The dependence of lymphoma diagnosis on morphology and particularly architecture leads to inherent challenges in making a specific diagnosis on needle core specimens. This presentation will also address some important caveats on this topic. Objectives: 1. Recognize the utility and necessity of ancillary testing in the diagnosis of lymphoma. 2. Discuss the use of FISH assays to provide prognostic information or precise classification in lymphoma diagnosis. 3. Describe the challenges and perils of small biopsies in lymphoma diagnosis.