Retroperitoneal Unicentric Castleman's Disease

An asymptomatic 35-year-old man received a routine examination in Memorial Sisli Hospital (Istanbul, Turkey). He had no feature in his medical history. A physical examination did not reveal any abnormal results and the patient's full blood count and biochemical profile were normal. Abdominal ultrasound examination revealed a 70 mm×50 mm solid hypoechoic mass lesion adjacent to the left lateral wall of the bladder. Abdominal contrast-enhanced computerized tomography revealed a 6.6 cm×5.2 cm×3.6 cm solid mass adjacent to internal iliac vessels and causing indentation left lateral wall of bladder. Due to the localization of the mass and possibility of extragonadal germ cell tumor, alpha-fetoprotein, lactate dehydrogenase, and beta human chorionic gonadotropin hormone values were requested and all results were within normal ranges. It was decided to surgically removal of the solid mass for a definitive diagnosis. Under general anesthesia, an upper midline incision was made and the peritoneal cavity was entered. Generalized abdominal exploration revealed only a solid mass below the left ureter and under the left iliac vessels. The solid mass freed up surrounding tissues. Sacral plexus branches were seen behind the solid mass. The solid mass was totally removed. The solid mass was a nodular structure, measuring 71 g, 6 cm×5.5 cm×4.5 cm in size. The patient was discharged on the 2^nd post-operative day. Histologic sections showed a lymph node with a preserved basic structure containing fibrous septae. Lymphoid follicles with one or more germinal centers, follicles with inconspicuous or regressed germinal centers, and follicles with thickened mantle zones were distributed within the lymph node. Small lymphoid cells were seen in the interfollicular area. Dilated congested vessels were observed in perinodal adipose tissue. No evidence of specific inflammation, event, or malignancy was found. Pathological examination consistent with hyaline vascular type of Castleman"s disease. Ultrasonography (USG) demonstrates homogeneous hypoechoic mass and computed tomography (CT) demonstrates a homogeneous mass with non-specific microcalcifications. USG and CT are not diagnostic as seen in our case.[] Although magnetic resonance imaging (MRI) is superior to CT as it shows soft-tissue better, it is not diagnostic for CD. Pre-operative fine-needle aspiration cytology has no role in diagnosis due to its low specificity. Therefore, a definitive diagnosis can only be made by pathological examination of the removed mass. Treatment methods may vary between unicentric and MCD. Standard treatment for UCD is en bloc surgical removal as performed in our case. Five-year survival rate after surgery is almost 100%. Recurrences are mainly reported in cases where surgical removal cannot be performed completely.[] Cytoreduction of radiotherapy has also been advocated in cases where complete resection is not feasible.[] There is no curative treatment for MCD. Corticosteroids, immunosuppressive drugs, chemotherapy, and radiotherapy have been tried for the treatment of MCD.[,,] Various rare benign tumors, primary or metastatic malignant tumors, can be seen in the retroperitoneum. CD should always be considered in the differential diagnosis of hypervascular masses detected in the retroperitoneum. Complete surgical removal of the mass is the most effective treatment for retroperitoneal UCD.