Image 3.

Castleman morphologic features more often present in unicentric symptomatic cases. A, This patient with unicentric Castleman disease (UCD) had fevers, fatigue, anemia, and slowed growth demonstrated hyperplastic germinal centers in his lymph node excision (×40). B, This symptomatic patient with UCD and fevers, joint pain and swelling, abdominal pain, and anemia had increased interfollicular fibrosis in her lymph node biopsy (×40). C and D, This patient with UCD died of paraneoplastic pemphigus. Histology demonstrated markedly expanded interfollicular regions comprising lymphocytes, numerous histiocytes, fibroblasts, plasma cells, and immunoblasts, with marked mantle zone regression; ×40 (C); ×20 (D). Flow cytometry did not identify any abnormal B- or T-cell proliferation. Immunohistochemical stains showed that most interfollicular lymphocytes were CD3-positive T cells, and the numerous histiocytes were highlighted by CD68 and CD163. Plasma cells were polytypic, and Epstein-Barr virus-encoded RNA in situ hybridization was negative.