Multicentric Castleman disease with splenic presentation: report of two rare cases with focus on histopathological features and review of the literature.

Castleman disease (CD) is a rare, heterogeneous, lymphoproliferative disorder that typically involves lymph nodes or, less commonly, extranodal sites such as the spleen. Based on clinical presentation CD is categorized into unicentric (UCD) and multicentric (MCD) forms, the latter further classified into HHV8-related, POEMS-associated, and idiopathic forms. We report two cases of HHV8-related MCD diagnosed on splenectomy specimens from patients presenting with splenomegaly, lymphadenopathies, and B symptoms. Histopathological analysis revealed mixed hyaline-vascular and plasma cell patterns with HHV8-positive lymphoid cells, and, in one case, an associated Kaposi sarcoma in splenic hilum lymph nodes. A systematic review of the literature identified 27 additional cases of CD diagnosed on splenectomy, which were analyzed alongside our two cases. Our study highlights that histologic evaluation of spleen tissue reliably reflects nodal CD patterns in both unicentric and multicentric forms and that, in selected cases, splenectomy remains a valuable diagnostic tool in Castleman disease.