Mediastinal Castleman disease presenting as a paraspinal mass causing back pain and shortness of breath in a young adult.

This case report details a rare presentation of unicentric Castleman disease (UCD), hyaline vascular type in a 22-year-old woman. The patient presented with a large, well-circumscribed mass in the paravertebral region causing back pain and shortness of breath. Diagnostic imaging and biopsy confirmed the diagnosis, and surgical excision led to a favorable outcome. This case underscores the critical need to include Castleman disease in the differential diagnosis for young adults presenting with mediastinal masses. Early recognition and surgical intervention are essential for a favorable prognosis in UCD cases.