Venous malformations (VM) are the most common congenital vascular anomaly and a frequent cause of chronic pain, yet clinical decision-making is often guided by isolated pieces of evidence rather than an integrated understanding of the disease. This narrative review synthesizes four studies conducted within a single-center, prospectively maintained vascular malformation registry (VASCOM, Bern, Switzerland, 2008-2022) to outline a coherent framework spanning phenotype, anatomical classification, genotype, and treatment outcome. In a cohort of 558 adolescent and adult patients with congenital vascular malformations, simple VM was the most common subtype and pain was the leading presenting symptom, with distinct complication patterns across malformation types. A revised phlebographic classification distinguishing non-lacunar from lacunar internal venous architecture was validated with high inter-reader reliability and carries direct implications for sclerotherapy dosing and technique selection. Genetic characterization of the same source population identified somatic PIK3CA variants in a subset of tested patients; non-hotspot variants were associated with higher variant allele frequency and were more common in syndromic presentations, underscoring the incomplete correlation between genotype and phenotype. Finally, a comparative cohort study of 227 patients demonstrated that alcohol embolization produced faster and more pronounced relief of mean and minimal pain than non-invasive management, but conferred no statistically significant advantage for maximal pain, at a minor (8%) and major (6%) complication rate. Considered together, these findings argue against a one-size-fits all approach to VM and support a stepwise pathway that integrates phenotypic recognition, anatomical characterization, selective genetic testing, and shared decision-making about invasive versus conservative pain management, anchored by disease-specific, patient-reported outcome measures rather than pain or imaging alone.