LAUSR

Castleman disease (CD) is an autoimmune, lymphoproliferative disease that shows itself with the enlargement of lymph nodes and varied clinical presentations originally described by Castleman in 1954. The incidence of CD is estimated at 21–25 cases per million personyears and the usual location is the mediastinum, although this pathology can theoretically affect any nodal station, extrathoracic sites have been reported in the neck, axilla, pelvis, and retroperitoneum. Renal cell carcinoma (RCC) ranks among one of the most prevalent tumors in China, with the estimated 66,800 new cases and 23,400 deaths in 2015. RCC often presents at an advanced stage. Nearly 30% of the patients are diagnosed with metastatic RCC (mRCC) at their first visit to hospital, which results in the poor prognosis. Enlarged hilar or retroperitoneal lymph nodes of RCC patients detected by CT or MRI commonly harbor the malignant change and metastasis. Whereas, comprehensive consideration should be taken, in case certain special cases would be misdiagnosed.