Unicentric Mesenteric Castleman Disease in an Adolescent: A Case Report

Introduction: Castleman's disease is a rare nonclonal lymphoproliferative disorder of unknown etiology that most commonly affects the mediastinum. It is classified into two clinical subtypes: A localized (unicentric) subtype and a multifocal (multicentric) subtype. This case report presents an adolescent with unicentric mesenteric Castleman's disease, which is very rare. Case Presentation: A 14-year-old girl presented to our center with chronic left flank pain. She also reported frequent episodes of small-volume vaginal bleeding outside her menstrual period. Initially, she was treated for several weeks with a possible diagnosis of dysmenorrhea due to an ovarian cyst. However, due to the lack of response to treatment and persistent symptoms, further investigation was conducted. Abdominal and pelvic ultrasonography revealed a round, hypoechoic, and heterogeneous mass measuring 22 × 35 mm in the left mesentery with regular margins. Pathological examination confirmed Castleman's disease of the hyaline-vascular type. The patient was discharged in good general condition and with stable vital signs. During follow-up, her abdominal symptoms and bleeding resolved, and no lesions were detected on ultrasonography and CT scans at 6 and 12 months. Conclusions: Mesenteric Castleman's disease is rare and presents a diagnostic challenge. This disease should be included in the differential diagnosis of abdominal tumors, even in symptomatic cases. The treatment of choice for unicentric cases is surgery.