Castleman lymphadenopathy: case review

Background. While examining regional lymph nodes removed with the tumor, the pathomorphologist is often limited to the exclusion of metastases, omitting changes in lymphoid tissue. The aim of the work is to describe a rare variant of Castleman-like lymphadenopathy in the surgical material obtained during the removal of colon cancer with regional lymph nodes. Methods. Pathomorphological examination of removed lymph nodes using histological and immunohistochemical methods (CD23). Results. A 73-year-old patient underwent surgery for rectal cancer. Pathomorphological analysis diagnosed adenocarcinoma of high degree of differentiation (G1) and revealed Castleman-like changes in some of the enlarged regional mesenteric lymph nodes: signs of different stages of development of lymphoid follicles, including their hyperplasia, atresia and fragmentation with preservation of activated CD23+ follicular dendritic cells and reaction of microvasculature, including vascular proliferation in the interfollicular areas with uneven narrowing of the sinuses. The discussion analyzes the probable genesis of changes in lymphoid tissue, which may be a reflection of the early stage of Castleman's disease, complication of radiation therapy performed in the preoperative stage, or a consequence of impaired immune status due to tumor growth, in particular with antigenic overloading of draining lymphoid tissue, effects of cytokines produced by inflammatory infiltrate cells that accumulate directly near the tumor, and the formation of a state of genetic instability, which progresses under the influence of radiation. Conclusion. Despite the rarity of Castleman-like lymphadenopathy, in each case of examination of lymph nodes in the surgical material it is necessary to conduct a thorough analysis of lymphoid tissue, as this may be important both to assess the prognosis and to select adequate therapy.