Radiotherapy for recurrent venous malformation involving the thigh and pelvic organs while preserving organ function: a case report.

Background: Venous malformations (VMs) are congenital vascular anomalies that cause significant pain and dysfunction. Although surgery is the primary treatment, no standardized guidelines exist for extensive or recurrent cases in which surgery is not feasible. Additionally, the role of radiotherapy (RT) in the management of VMs remains unclear. Methods: A 24-year-old woman with extensive, recurrent VM involving the pelvic cavity, right thigh, and buttocks underwent multiple surgeries and sclerotherapy for over 10 years; however, the disease progressed, infiltrating the pelvic organs, and posed a risk to fertility. The patient presented with severe pain, ureteral obstruction, and menstrual irregularities, all of which significantly affected her quality of life. Considering the high morbidity associated with further surgery, definitive RT was performed. The patient received intensity-modulated radiotherapy (IMRT) at a total dose of 43 Gy in 20 fractions, preceded by ovarian transposition to preserve fertility. Results: After the treatment, the patient experienced remarkable symptom relief, including pain resolution and improvement in menstrual regularity. Follow-up imaging over five years demonstrated a continued reduction in the lesion size. The menstrual cycles remained regular, and anti-Müllerian hormone levels remained within the normal range. Conclusion: This case demonstrates the potential of RT as an effective treatment for extensive, recurrent pelvic VMs. RT achieves durable disease control while preserving ovarian function, highlighting its role as a viable alternative in select cases.