Hematopoietic and Reticuloendothelial Systems

T-C42 designates neoplasms that arise in the hematopoietic and reticuloendothelial systems, encompassing organs and tissues responsible for blood formation and immune function such as bone marrow, spleen, thymus, lymph nodes and associated lymphoid tissue. It is used in the ICD-O-3 to code cancers of these sites.