Hodgkin's disease with coexistent Castleman-like histologic features. A report of three cases.

We report three cases of Hodgkin's disease with coexistent histologic features reminiscent of Castleman's disease. In each case, reactive follicular hyperplasia was prominent and lymphoid follicles contained normal- or small-sized germinal centers. In two lesions, sheets of mature plasma cells and vascular proliferation were present in the interfollicular region, and some of the follicle centers were small, relatively depleted of lymphoid cells, and surrounded by concentric layers of small lymphocytes (so-called onionskin layers). However, unequivocal hyaline-vascular lesions were absent. Both cases were referred with the diagnosis of Castleman's disease, most consistent with the plasma cell variant. Subsequent review demonstrated scattered Reed-Sternberg and Hodgkin cells in the interfollicular region, highlighted by immunohistochemical studies, and the diagnosis of interfollicular Hodgkin's disease was made. In the third lesion, the majority of the lymph node was replaced by Hodgkin's disease, nodular lymphocyte predominance subtype. In the regions not involved by tumor, reactive lymphoid follicles with hyaline-vascular lesions were numerous. This case was also referred with the diagnosis of Castleman's disease, of the hyaline-vascular type. We report these lesions to emphasize that histologic features reminiscent of Castleman's disease may occur in lymph nodes involved by Hodgkin's disease, resulting in diagnostic confusion. Castleman-like histologic features may represent a nonspecific immune response to a variety of immunologic stimuli including, as in these cases, the presence of Hodgkin's disease. The possibility of Hodgkin's disease needs to be considered and excluded before the diagnosis of Castleman's disease is made.