Retroperitoneal Castleman's disease: benign in the midst of malignancy.

A 32-year-old asymptomatic woman presented with localised mass on the left side of the abdomen for 8 months. An abdominal ultrasound and CT scan revealed a solid heterogenous mass located just below the left kidney in the retroperitoneum. Provisional diagnosis of soft tissue sarcoma was made. Following this, surgery was planned and open biopsy (frozen section) was performed, which demonstrated localised hyaline-vascular type of Castleman's disease, which was then excised completely. Thus, intraoperative diagnosis avoided extensive resection and radiation therapy, which reduced the patient's morbidity and expenses. Postoperative period was uneventful and no recurrence was seen even after 3 years of follow-up.