Retroperitoneal mass a diagnostic masquerade: a case report of unicentric Castleman’s disease

Introduction: Castleman disease is a lymphoproliferative disorder with a nondefinite etiology that mostly occurs in the chest and neck. Lesions originating in the retroperitoneum are rare. Clinically, it manifests as a more common unicentric and less common multicentric disease commonly seen in younger age groups. Unicentric Castleman’s disease (CD) can sometimes be misdiagnosed as non-Hodgkin lymphoma or paraganglioma, so definite immunohistochemistry studies are essential. Presentation of case: A 23-year-old woman was referred to our hospital due to a retroperitoneal tumor on the left side anterior to the lower pole of her left kidney spanning over L3-L4 vertebral level on a computed tomography scan. A core biopsy suggests paraganglioma. Laparoscopic tumorectomy was performed, and the pathological diagnosis was CD, hyaline vascular and plasma cell type. Discussion: Regardless of presentation, CD is rarely included in differential diagnosis, so a multispecialty review is highly recommended for establishing the diagnosis. Conclusion: We herein report a rare case of Retroperitoneal CD. The patient was successfully treated with a planned laparoscopic tumorectomy.