Safety and efficacy of interstitial bleomycin sclerotherapy for foam sclerosant-infeasible small solid venous malformations in the lower extremity

Purpose To evaluate the safety and efficacy of interstitial bleomycin sclerotherapy for treating small painful venous malformations (VMs) in the lower extremities. Methods Between September 2022 and August 2024, 256 patients underwent 420 sclerotherapy sessions for slow-flow vascular malformations. Exclusions included sponge-form VMs, lymphatic malformations, fibroadipose vascular anomalies, and syndromic vascular anomalies. Thirteen patients with solid VMs in the lower extremities, unresponsive to prior foam sclerotherapy ( n = 6) or with vascular access challenges due to the lesion’s solid nature ( n = 7), underwent 19 interstitial bleomycin sclerotherapy sessions. Pre- and post-treatment assessments included visual analog scale (VAS) scores and imaging findings for lesion diameter and vascularity. Results Nineteen bleomycin sclerotherapy sessions were conducted in 13 patients. VMs were intramuscular ( n = 11), in the sub-fascial fat layer ( n = 1), or both ( n = 1). The mean interval between prior foam and bleomycin sclerotherapy was 818 days, with a 254-day follow-up after treatment. Pain improved in 92% of patients, with a VAS score reduction from 8.5 to 2.8 ( p = .0001). One patient showed no improvement after three sessions. Among six patients with vascularity detected on Doppler ultrasound pre-treatment, all demonstrated resolution post-treatment ( p = .0313). Mean diameter reduction of 0.27 cm was not statistically significant ( p = .0573). Three minor/moderate adverse events occurred: allergic reactions and skin pigmentation. Conclusion Interstitial bleomycin sclerotherapy is a safe and effective option for reducing pain and vascularity in lower extremity solid VMs unresponsive to foam sclerotherapy or presenting poor vascular access.