Castleman's disease of the left triceps in a child suspected to be a smallround cell tumor of childhood

Castleman's disease (CD) is histologically characterized by a proliferation of polyclonal small lymphocytes and plasma cells. The clinical presentatio n varies widely, but. most commonly manifests as a solitary mediastinal mas s, incidentally found on radiographic examination. We present a case of a 1 0-year-old girl who exhibited a left arm mass which, preoperatively and on frozen section, was diagnosed as a small round cell tumor of childhood (SRC T). This report emphasizes the unusual location of CD in the soft tissue an d as a rare entity to be considered in the differential diagnosis of SRCT.