Cytological diagnosis of Castleman's disease of the soft tissue.

Castleman's disease (CD), a rare benign disease is characterized by lymphoid hyperplasia of uncertain etiology that may present as a nodal or extranodal mass. We describe herein a rare case of CD occurring in the soft-tissue of right arm in a 55-year-old woman. The present case is instructive in the differential diagnosis of primary soft-tissue tumors, for which the possibility of CD should be considered. On clinical examination as well as gross examination, this disease mimics lymphomas and tuberculosis. Since cytological appearances vary depending on the type and extent of hyperplasia, fine needle aspiration cytology findings may not always be conclusive in all cases. We studied aspirates which revealed reactive hyperplasia with increased vascularity. Excision confirmed the diagnosis.