Extranodal multicentric Castleman's disease with cutaneous involvement.

Castleman's disease (CAD) is an unusual lymphoid hyperplasia that might be induced by an immunologic reaction to a virus or another infectious organism or drug. CAD commonly occurs in the mediastinal lymph nodes and less frequently in the neck lymph nodes, but other lymph nodes might be involved. Extranodal CAD is rare. We present a 72-year-old woman with diffuse 2- to 5-cm cutaneous nodules that had appeared a few months earlier. The patient underwent a biopsy, and the lesions resolved within 4 months. The patient was asymptomatic except for mild joint pains. Histopathologic findings showed a circumscribed nodule composed of lymphoid follicles with contracted germinal centers and expanded mantle zones. The lymphoid follicles were separated by perivascular bands of sclerotic collagen. Aggregates of epithelioid and dendritic histiocytes were present between follicles, with a prominent lymphoplasmacytic infiltrate and vascular proliferation. Although extranodal CAD has been reported in the skin, we think that this is the first reported case of multicentric cutaneous CAD without evidence of lymph node involvement.