# Unicentric Hyaline-Vascular Castleman Disease Presenting as a Periduodenal Mass: A Rare Retroperitoneal Manifestation

## TL;DR

A rare case of Castleman disease is reported as a mass near the duodenum, emphasizing the need to consider this condition in unusual retroperitoneal locations.

## Contribution

The paper presents a rare retroperitoneal manifestation of unicentric hyaline-vascular Castleman disease near the duodenum.

## Key findings

- A 46-year-old male was diagnosed with unicentric hyaline-vascular Castleman disease via biopsy and surgical resection.
- The disease presented as a retroperitoneal mass posterior to the duodenum, an atypical location for Castleman disease.
- The case underscores the importance of including Castleman disease in the differential diagnosis of retroperitoneal masses.

## Abstract

Castleman disease (CD) is a rare lymphoproliferative disorder, typically presenting in the mediastinum. We report a case of a 46-year-old male with back and abdominal pain found to have an incidental 3.9 cm retroperitoneal mass posterior to the duodenum. Endoscopic biopsy revealed atypical B-cell proliferation, and surgical resection confirmed unicentric hyaline-vascular CD. This case highlights a rare periduodenal presentation and underscores the importance of including CD in the differential diagnosis of retroperitoneal masses, even in atypical locations, to ensure timely recognition and management.