Localized retroperitoneal mass suspected malignancy: A rare case of unicentric Castleman's disease

Key Clinical Message Castleman's Disease should be considered in the differential diagnosis of retroperitoneal masses, especially in equivocal cases. Clinician should not presume all cases of retroperitoneal masses as a malignancy. Abstract Castleman's Disease is a heterogeneous group of lymphoproliferative disorders, that can develop in lymph nodes or in extranodal sites. It has three distinct histological subtypes; hyaline vascular, plasma cell or mixed. It can be unicentric or multicentric, and sometimes oligocentric or regional. In this article, we report a case of a 30‐year‐old male who presented with a palpable left lumbar mass, clinically suspected as sarcoma vs GIST, which was surgically excised and pathologically examined revealing a rare condition of intra‐abdominal unicentric Castleman's Disease with good prognosis. Castleman's Disease should be considered in the differential diagnosis of retroperitoneal masses, especially in equivocal cases.