Abstract
BACKGROUND: Castleman disease (CD) is a rare lymphoproliferative disorder most commonly occurring in the mediastinum and hilar regions. Mesenteric involvement is rare, and diagnosis primarily relies on histopathological examination. CASE SUMMARY: We report two cases of mesenteric CD with gastrointestinal symptoms accompanied by weight loss. Case 1 underwent complete surgical resection of the lesion. Postoperative pathology confirmed the hyaline vascular type, and the prognosis was favorable. Case 2 also underwent complete surgical resection initially, with postoperative pathology confirming the plasma cell type. However, the disease followed an aggressive course. A second surgery was performed five months later, and postoperative pathology confirmed mesenteric peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS). The patient died postoperatively due to acute renal failure. CONCLUSION: To our knowledge, this is the first reported case of mesenteric CD transforming into PTCL-NOS, highlighting the complexity and heterogeneity of the clinical course of mesenteric CD. These findings provide insights into the personalized treatment and clinical management of this disease.