Basic Concepts in Lymph Node Pathology

Abstract

Lymphomas are clonal neoplasms of mature and immature B, T, and NK cells at various stages of differentiation. Currently, tumors of hematopoietic and lymphoid tissues are classified according to the 2016 revision of the World Health Organization (WHO) classification which integrates clinical and pathological information (immunohistochemistry, flow cytometry, cytogenetics, and molecular studies) to define disease entities. The accurate diagnosis and classification of benign and malignant conditions in lymph node pathology require the availability of adequate tissue for morphological assessment and ancillary investigations. Excisional lymph node biopsy is the preferred specimen, and it should be submitted fresh for “lymphoma work-up” during which the tissue is divided and submitted for flow cytometry, cytogenetic and molecular studies, and paraffin processing (the work-up may vary among different institutions).