Intramuscular Castleman's disease of the deltoid: a case report and review of the literature.

Castleman's disease (CD), a rare benign disease characterized by lymphoid hyperplasia, typically arises in the mediastinum as a solitary tumor. We describe herein a rare case of intramuscular CD occurring in the left deltoid in a 28-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.