Cutaneous involvement as initial presentation of multicentric plasmacytic Castleman disease.

Castleman disease (CD) is an unusual lymphoproliferative disorder characterized by multiple lymphadenopathy accompanied by marked systemic inflammatory symptoms. CD can be unicentric (UCD) or multicentric (MCD), and it can be classified into three types based on histopathology: hyaline vascular type, plasma cell type, and mixed hyaline vascular and plasma cell type. CD involving skin is an unusual clinical manifestation. Abnormalities including rash, hyperpigmentation, cherry hemangiomatosis, paraneoplastic pemphigus, and Kaposi sarcoma have been reported to occur in MCD. Here, we reported an unusual case of MCD which presented initially with disseminated dark brown papules, patches, and plaques, and pathologically demonstrated plasma cell type CD, a finding which is rarely reported. The peculiar clinicopathological features will be discussed.