Angiogenesis in Renal Cell Carcinoma: Molecular Biology, Clinical Manifestations, and Case-Based Insights

Angiogenesis is the defining biological feature of clear-cell renal cell carcinoma (ccRCC). Loss of Von Hippel–Lindau (VHL) function stabilises hypoxia-inducible factors (HIFs), upregulating vascular endothelial growth factor (VEGF) and allied mediators that produce a hypervascular, leaky, and fragile tumour vasculature. This chapter offers a concise, clinically oriented review of renal cell carcinoma (RCC) angiogenesis centred on an exceptional case: a right-sided ccRCC with intratumoral arteriovenous (AV) shunting and venous collaterals that communicated with the second part of the duodenum, presenting as severe upper gastrointestinal (GI) bleeding. We translate the mechanism into management, emphasising rapid stabilisation, diagnostic angiography, endovascular embolisation, and definitive surgery; then situate contemporary systemic therapy [VEGF/VEGF receptor (VEGFR) tyrosine kinase inhibitors (TKIs), immuno-oncology–TKI (IO–TKI) combinations, and HIF-2α inhibition] within decision frameworks that clinicians can apply. An expanded discussion links vessel biology to imaging signatures, resistance, perioperative strategies, and follow-up care. This case serves as a central framework for demonstrating how timely, multidisciplinary coordination can prevent catastrophic haemorrhage and ensure durable oncological control.