Klippel-trenaunay syndrome with multifactorial anemia:successful management with sirolimus

Abstract Objective：Klippel-Trenaunay Syndrome (KTS), a rare congenital disorder characterized by capillary malformations, venous varicosities, and limb hypertrophy is rarely associated with autoimmune hemolytic anemia (AIHA). We present a complex KTS case complicated by transfusion-induced anemia，IDA，wAIHA，and consumptive coagulopathy, highlighting diagnostic challenges and therapeutic innovation.Methods：A 25-year-old female with confirmed KTS and recurrent rectal bleeding presented with severe anemia (Hb 29 g/L). Following multidisciplinary evaluation including serology, imaging (Doppler ultrasound, CTA), endoscopy, and bone marrow biopsy, we initiated:Immunomodulatory therapy: IV immunoglobulin (20g/day ×3d), methylprednisolone (80mg/day tapered to 4mg/day)，Sirolimus (1mg/day escalated to 2mg/day maintenance)，Supportive care: Iron, B12, folate supplementation，Longitudinal monitoring of hematologic/coagulation parameters and splenic volume.Results：Recurrent transfusion reactions were attributed to anti-Rh-Ec antibodies (Direct Coombs+: IgG/C3d), confirming AIHA. Colonoscopy revealed rectal/sigmoid varices as chronic bleeding source, while CTA demonstrated splenomegaly (243mm) with cystic lesions and systemic venous dilation. Therapeutic response within 4 months:Hb increased from 2.7 to 11.9 g/dL and Platelets normalized (98→218×10³/mm³)，Coagulation improved: Fibrinogen ↑ (1.83→3.01 g/L), D-dimer ↓ (11.74→0.81 mg/L)，Splenic volume reduced by 18% radiographically ；No further hemolytic crises or transfusion requirements；Coagulopathy reversal: Declining fibrinogen (1.83 g/L) and elevated FDPs suggested evolving Kasabach-Merritt phenomenon (reported in 36% of KTS; Peng et al., Prenat Diagn 2006), which was mitigated by SirolimusConclusions：This case demonstrates: 1. KTS-associated vascular anomalies can precipitate life-threatening AIHA through antibody generation from chronic transfusion, necessitating rigorous blood group compatibility screening 2. mTOR inhibition Sirolimus– targeting PIK3CA-related pathogenesis – may concurrently ameliorate coagulopathy and vascular overgrowth. 3. Splenectomy remains indicated for massive splenomegaly with hypersplenism despite medical therapy. Early multidisciplinary intervention is critical to address the triad of hemorrhage, hemolysis, and coagulopathy in complex KTS.Key words：Klippel-Trenaunay Syndrome，Anemia，Sirolimus