Comparative Pathomorphology of Lymph Node Changes in Kikuchi-Fujimoto and Autoimmune Diseases with Lymphadenopathy: Own Experience

Abstract

Background. Pathomorphological analysis of lymph node tissues in immune-mediated lymphadenopathies commonly presupposes differential diagnosis with tumors of lymphoid and myeloid tissues with partial lesions in lymph nodes. Besides, further study is required on pathogenetic relationship between autoimmune diseases with lymphadenopathy and Kikuchi-Fujimoto disease (KFD) with morphological substrate characterized by histiocytic necrotizing lymphadenitis. Aim. To compare, based on biopsy material, morpho-immunohistochemical characteristics of changes in lymph node tissues in patients with pathomorphological diagnosis of KFD and in patients with autoimmune diseases with lymphadenopathy, i.e. systemic lupus erythematosus (SLE) and adult Still's disease (ASD). Materials & Methods. Morphological and immunohistochemical analyses were carried out on lymph node biopsies of 20 patients, 16 out of them with KFD (men/women 15:1, median age 26.5 years, range 18-47 years; in 44 % of cases lesions were only in cervical lymph nodes). In 2 female patients (aged 19 and 33 years) SLE was diagnosed based on clinical and laboratory data, and 2 patients (a woman aged 43 years and a man aged 25 years) were diagnosed with ASD. Results. Morphological and immunohistochemical analyses detected three major cell populations similar in KFD and SLE and probably reflecting pathogenetic relationship of these diseases: histiocytes expressing myeloperoxidase (MPO+), CD123+ plasmacytoid dendritic cells, cytotoxic CD8+ T-cells, and granzyme B+. In 55 % of KFD cases and 2 SLE cases there were many activated CD30+ lymphoid cells clustered and scattered in the areas of cytotoxic T-cells. Conclusion. To exclude SLE during subsequent additional examination of patients with morphological substrate characterized by histiocytic necrotizing lymphadenitis it is reasonable to use the term “Kikuchi-like changes” instead of KFD. When the data of immunohistochemical analysis in KFD, SLE, and ASD patients are compared, MPO+ histiocytes in lymph node tissue can serve as diagnostic immunohistochemical marker of immunoinflammatory process. If they are detected, differential diagnosis with myeloid sarcoma is required. CD30 expression by activated cytotoxic lymphoid cells was identified in SLE and in 55 % of KFD cases, which is another important common diagnostic characteristic of the substrate of two diseases (KFD and SLE) and requires differential diagnosis with anaplastic large-cell lymphoma and Hodgkin's lymphoma. Within the analyzed group of 20 patients morphological substrate of lymph nodes in 2 ASD patients differed in its morphological and immunohistochemical parameters from that in KFD and SLE patients and was characterized by expanded paracortex and morpho-immunohistochemical characteristics of extrafollicular B-cell activation.