Interleukin-6-producing dermoid cyst associated with multicentric Castleman's disease.

Dysregulated overproduction of interleukin-6 (IL-6) from activated B cells in affected lymph nodes has been implicated in the pathogenesis of multicentric Castleman's disease (MCD), a rare lymphoproliferative disorder accompanied by systemic manifestations. We here report the case of a 32-year-old female presenting with MCD associated with a dermoid cyst in the pelvic cavity. The co-occurrence of MCD and dermoid cyst has not been reported before. Immunohistochemical analysis of the tissue sections showed IL-6 production in CD68-positive macrophage cells, which had infiltrated the dermoid cyst. Removal of the cyst resulted in partial improvement in systemic symptoms accompanied by a decrease in serum IL-6, while complete improvement was obtained by treatment with an anti-IL-6 receptor antibody following resection of the dermoid cyst. To the best of our knowledge, this is the first study to provide evidence of IL-6 production by CD68(+) cells in a dermoid cyst involved in MCD.