The 5th edition of the WHO Classification of Hematolymphoid Tumors subcategorizes the dendritic cell neoplasms under the spectrum of histiocytic/dendritic cell neoplasms based on their histogenesis and their distinct immunophenotypic profile (positive for CD45, CD4, CD68, CD163, and lysozyme). The gene discussed is LYZ; the disease is dendritic cell tumor.