Inflammatory Pseudotumor of Lymph Nodes Definition Inflammatory pseudotumor (IPT) of lymph node is a histiocytic and fibroblastic non-neoplastic proliferation involving the lymph node connective tissue framework and associated with vascular…
Palisaded Myofibroblastoma Definition Benign mesenchymal lymph node tumor characterized by palisading spindle cells, stellate deposits of collagen (amianthoid fibers), and hemorrhage. Synonym Intranodal hemorrhagic spindle cell tumor with amianthoid fibers….
Lymphomas Associated with Acquired Immunodeficiency Syndrome (AIDS) Definition This is a heterogeneous group of Hodgkin lymphomas and non-Hodgkin lymphomas arising in persons with severe acquired immunodeficiency syndrome (AIDS) induced by…
Dendritic Cell Neoplasms Histiocytes have two broad functions: antigen processing and antigen presentation. In Chapter 77, the focus was on neoplasms derived from antigen-processing cells; that is, phagocytic histiocytes/macrophages. In…
Introduction Benign and malignant neoplasms of nonlymphoid cell components of lymph nodes are remarkably rare. They may have a vascular origin (see Part IX) or arise from a variety of…
Lymphoproliferative Disorders Associated with Congenital Immune Deficiencies Definition A lymphoproliferative disease arising in the setting of a primary immune deficiency (PID) or a primary immunoregulatory disorder (1). Epidemiology Congenital immunodeficiency…
Post-Transplant Lymphoproliferative Disorders Definition Post-transplant lymphoproliferative disorders (PTLDs) are lymphoid proliferations that arise in patients who have undergone solid organ or bone marrow transplantation (1). PTLDs are heterogeneous, encompassing a…
Anaplastic Large-Cell Lymphoma Anaplastic large-cell lymphoma (ALCL) was originally designated as Ki-1 lymphoma by Stein and colleagues in 1985 (1). The name was based on the constant and uniform positivity…
Introduction The immune system, composed of a multitude of interdependent humoral and cellular components, as well as non-specific host defense mechanisms (e.g., phagocytes), defends the body against environmental pathogens. Deficiencies…
Histiocytic Sarcoma Definition As defined in the World Health Organization (WHO) classification, histiocytic sarcoma is a malignant neoplasm composed of cells with histologic and immunophenotypic features similar to those of…
