Renal clear cell carcinoma (RCC), the predominant subtype of kidney cancer, is characterized by paraneoplastic syndromes, of which membranous nephropathy (MN) represents the most common paraneoplastic glomerulonephritis. While phospholipase A2 receptor (PLA2R) antibodies indicate primary MN, the concurrent presence of light-chain amyloidosis may further complicate the clinical manifestations in malignancy-associated cases. A rare case of RCC concurrent with phospholipase A2 receptor PLA2R-positive MN and light chain amyloidosis is reported in this paper. An elderly male patient presented with nephrotic syndrome and a right renal mass. The patient underwent a nephrectomy after admission. Pathological examination confirmed the diagnosis of right kidney renal clear cell carcinoma. Renal biopsy revealed PLA2R-positive MN and AL amyloidosis. Interestingly, in this case, glomerular light chain staining showed no monoclonal restriction, but λ light chain deposition was found in the vessels. However, the nephrotic syndrome showed no improvement after tumor resection. The patient achieved remission following sequential treatment with bortezomib, dexamethasone, daratumumab, and rituximab. This case illustrates the complex interplay among RCC, PLA2R-positive MN, and AL amyloidosis, complicating patient management. Future research should focus on the immunological mechanisms of PLA2R antibody production in malignancy and the pathophysiological links among these conditions. Clinicians should remain vigilant for secondary causes of nephrotic syndrome in renal malignancy patients and adopt comprehensive, multidisciplinary approaches to improve outcomes.
Zhang et al. (Wed,) studied this question.