Paraneoplastic syndrome (PNS), as a common systemic complication in renal cancer patients, exhibits complex and diverse clinical manifestations involving multiple organ systems. In elderly renal cancer patients, PNS demonstrates more distinctive clinical features closely associated with age-related physiological decline, immunosenescence phenomena, and multimorbidity status. Age-related pathophysiological alterations—including progressive immune dysregulation, persistent low-grade inflammatory responses, and metabolic disorders—collectively constitute the critical pathogenic basis for PNS development in elderly renal cancer patients. However, current research on PNS in elderly renal cancer patients remains shrouded in multiple unresolved mysteries, with a notable absence of consensus across studies regarding the interpretation of pathogenesis and the selection of therapeutic regimens. This study presents a clinically significant case of an elderly renal cancer patient with PNS who did not undergo surgical intervention, demonstrating complex disease progression and diverse clinical manifestations. Through a comprehensive review and in-depth analysis of existing literature, we systematically investigated critical aspects of PNS including its pathogenesis, clinical characteristics, prognostic factors, and therapeutic strategies. This comprehensive analysis not only helps deepen the understanding of the essential characteristics and clinical implications of PNS, but more importantly provides valuable reference basis for clinical practice. We anticipate that this research will facilitate the refinement of diagnostic and treatment protocols for renal cancer-associated PNS, guide clinicians in formulating more precise personalized treatment regimens, and thereby effectively improve patients’ quality of life and long-term prognosis.