This chapter discusses non-Hodgkin lymphomas, plasma cell neoplasms and histiocytic or dendritic cell neoplasm. Non-Hodgkin lymphomas are a heterogeneous group of malignancies. Their clinical presentation and course vary from indolent to aggressive. Indolent lymphomas are often disseminated at the time of diagnosis and frequently involve bone marrow. Over the last decade, significant progress has been made in the molecular characterizations of lymphomas, but the classification of lymphomas is still evolving. The prognosis of non-Hodgkin lymphomas depends on the type, the stage, and the cytogenetic and molecular features. This chapter covers the comparison of immunophenotype of small B-cell lymphomas, follicular lymphoma (FL), mantle cell lymphoma (MCL), diffuse large B-cell lymphoma (DLBCL), comparison of T-cell or histiocyte rich large B-cell lymphoma (THRLBCL) and nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), Burkitt lymphoma (BL), mature T-cell and natural killer (NK) cell neoplasm, angioimmunoblastic T-cell lymphoma (AITL), molecular and cytogenetic features of anaplastic large cell lymphoma (ALCL), plasma cell neoplasms, monoclonal immunoglobulin and plasma cell disorders, osteosclerotic myeloma (POEMS Syndrome), histiocytic and dendritic cell neoplasms, juvenile xanthogranuloma (JXG), and Erdheim-Chester disease.