Renal Neoplasms with Concurrent Castleman-Like Regional Lymphadenopathy.

Introduction: Renal cell neoplasms are known to be associated with paraneoplastic syndromes, and the association with Castleman-like regional lymphadenopathy has been rarely reported. We aim to characterize the association between renal neoplasms and Castleman-like lymphadenopathy.

Methods: A search for renal neoplasms with concurrent Castleman-like lymphadenopathy in one single medical institution from 2000 to 2023 resulted in 4 specimens. A literature search for "Castleman" and "renal neoplasm" resulted in 8 reports. Patients' demographics, clinical presentation, gross and histologic features, results of ancillary studies, treatment, and follow-up were evaluated.

Results: Our patients included 3 men and 1 woman, with a mean age of 60 years. Four different subtypes of renal neoplasms were diagnosed, including clear cell renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, and mucinous cystadenoma of the renal pelvis. For Castleman-like regional lymphadenopathy, 2 were plasma-cell predominant, and 2 were hyaline-vascular. After a median follow-up of 84 months, all patients were alive with no recurrence or progression of Castleman-like features following nephrectomies.

Conclusion: Castleman-like regional lymphadenopathy should be considered in patients with renal tumors and lymphadenopathy. Although more prevalent in clear cell RCC, it can be also associated with other renal neoplasms. The concurrent lymphadenopathy was remitted following the renal tumor resections.