Castleman's disease of the spleen.

Castleman's disease (CD) is a rare lymphoproliferative disorder of unknown etiology. Clinically, it occurs as a localized (unicentric) disease or as a systemic (multicentric) disease. Unicentric Castleman's disease (UCD) presents as a solitary mass and primarily affects the mediastinal, retroperitoneal, and cervical lymph nodes. In contrast to multicentric CD, which involves peripheral lymphadenopathy and numerous systemic symptoms, UCD is not typically associated with generalized symptoms. Three main distinct histologic variants are recognized: hyaline-vascular type, plasma cell type, and mixed type. Extranodal CD is rare. Specifically, UCD exclusively in the spleen is extremely rare, with only 2 cases described in the literature to date. Here, we describe an asymptomatic 75-year-old man with a 5.7 cm × 4.5 cm sized heterogenous enhanced mass located in the spleen. He underwent surgical resection for diagnosis and treatment. A pathologic examination indicated the hyaline-vascular type of CD. In this patient, the preoperative diagnosis was difficult to determine, and therefore, invasive procedures were required.