Venous malformations (VMs) are congenital, low-flow vascular anomalies that may be present at birth but are often diagnosed later. While benign, they can cause significant morbidity, including pain, swelling, functional impairment, cosmetic concerns, and localized intravascular coagulopathy (LIC). Complications include thrombosis, phleboliths, and LIC, which may increase the risk of consumptive coagulopathy during interventions. According to the updated ISSVA Classification (2025), vascular malformations are divided into high-flow and low-flow lesions, a distinction that guides diagnosis and therapy. Low-flow malformations are frequently associated with PIK3CA mutations, whereas high-flow lesions are more commonly driven by RAS-pathway mutations. Diagnosis involves clinical assessment, D-Dimer testing (LIC), duplex ultrasound to evaluate superficial and deep venous systems as well as to separate high flow malformations, and contrast-enhanced MRI to define lesion type, extent, and bone involvement. Direct phlebography provides detailed morphological and drainage information. Genetic testing for somatic variants is recommended by VASCERN guidelines to guide targeted therapies. Treatment is tailored and multidisciplinary. Conservative measures include compression garments and selective anticoagulation (low dose in LIC, full dose in DVT). Interventional therapy with embolo-sclerotherapy using ethanol, polidocanol, or bleomycin is the mainstay for complex lesions, guided by phlebographic classification. Surgery is reserved for well-circumscribed lesions, often in combination with sclerotherapy, although incomplete resection carries a risk of recurrence. Targeted systemic therapy is indicated for extensive, unresectable, or symptomatic malformations. Sirolimus (mTOR inhibitor) provides symptom control, while Alpelisib (PI3K inhibitor) shows promise in PIK3CA-related overgrowth syndrome (PROS), with dosing individualized in pediatric patients and FDA-approved for patients over 2 years. Effective VM management relies on accurate diagnostic classification, genetic characterization, and personalized treatment, integrating conservative, interventional, surgical, and targeted approaches to optimize outcomes. References • Orphanet Journal of Rare Diseases (2024) 19:213. Assessment of gene-disease associations and recommendations for genetic testing for somatic variants in vascular anomalies by VASCERN-VASCA. DOI: 10.1186/s13023-024-03196-9 • JCI Insight (2023) 8(21):e173095. Preliminary results of the European multicentric phase III trial regarding sirolimus in slow-flow vascular malformations. DOI: 10.1172/jci.insight.173095 • Clinical Cancer Research (2024) 30(1):23–28. FDA Approval Summary: Alpelisib for PIK3CA-Related Overgrowth Spectrum. DOI: 10.1158/1078-0432.CCR-23-1270 • ISSVA Classification of Vascular Anomalies 2025. International Society for the Study of Vascular Anomalies. https://www.issva.org/classification