Controversies in the Current Hematopathology Practice and Classification of Hematopoietic and Lymphoid Neoplasms

Historically, classification of lymphoid neoplasms has been a controversial topic from the very beginning. The early classification schemes suffered from poor insights into the nature and lineage of neoplastic cells and were based on subjective assumptions by the classification authors. Unsurprisingly, numerous competing classification systems were proposed over the years prior to the modern immunophenotyping, cytogenetics, and molecular genetics era and those were reviewed elsewhere [1]. On the other hand, some of the hematology terminology were coined early on in the discovery process, and despite their limitations and legacy problems, they persist in use to this day, making hematopathology a very confusing subject to teach. Fortunately, the modern approach to classifying lymphoid neoplasms based on immunophenotyping, cytogenetics, molecular genetics, and evidence-based medicine was very successful and culminated in the popular Revised European-American Lymphoma (REAL) classification and later World Health Organization (WHO) classifications, most recently published in 2008 [2-4].