Internal Iliac Vein Reflux: An Underrecognized Pathophysiology in Klippel-Trénaunay Syndrome With Pelvis Involvement

Background and objective Internal iliac vein reflux (IIVR) has been underrecognized in Klippel-Trénaunay syndrome (KTS) with pelvis involvement. In this study, our aim was to report clinical and radiological characteristics, modified phlebography technique, and diagnostic and treatment algorithm and outcomes of IIVR in KTS patients with pelvis involvement. Materials and methods KTS patients diagnosed between May 2014 and January 2021 were retrospectively analyzed. The medical records and imaging studies of all patients with KTS of the lower extremities were included and reviewed. KTS was defined as the triad of capillary malformation, venous malformation, and limb overgrowth. Pelvis involvement was evaluated with MRI. Phlebography was performed if IIVR was suspected. IIVR ablation and sclerotherapy were performed if IIVR was confirmed in KTS patients with external genitalia/perineum manifestation and bleeding. Patients were followed up via outpatient consultations. Episodes of gross bleeding were specifically investigated. Results A total of 211 patients with lower limb KTS diagnosed by our team were included in the study. Unilateral IIVR was diagnosed in 97 patients, and bilateral IIVR in two patients; 117 KTS patients were managed with radiological intervention and/or hybrid surgery by our team. Eleven patients underwent an IIVR ablation procedure due to recurrent bleeding from pelvic organs. Postprocedural complications included transient fever (n=2) and mild anaphylactic reaction (n=1). A small hyperpigmented scar at the incision and/or accessing site was noticed in patients receiving bleomycin during the procedure (n=6). Bleeding episodes and anemia resolved in all patients during the follow-up period. Correspondingly, the involved IIV and its tributaries were found to have disappeared on imaging during the follow-up. Conclusion IIVR is common in KTS patients, and it can cause bleeding from pelvic organs. Bleeding can be managed with IIVR ablation and sclerotherapy in KTS with pelvis involvement.