Cutaneous and systemic plasmacytosis is a rare condition primarily affecting middle-aged individuals of Japanese descent and has principally been reported in cases originating from Asia. Its relationship, if any, to Castleman disease, is controversial. The authors report a case of cutaneous and systemic plasmacytosis involving a 36-year-old man of Chinese ancestry born in North America. The biopsy of an involved lymph node revealed changes resembling Castleman disease. Significantly, this case to our knowledge represents the first case of cutaneous and systemic plasmacytosis presenting in a patient of Chinese ancestry born on the North American mainland.