Pediatric Intraosseous Arteriovenous Malformation of the Mandible: A Therapeutic Challenge

Abstract

Intraosseous arteriovenous malformations (AVMs) of the mandible are rare but potentially life-threatening vascular anomalies in childhood. We report the case of a 7-year-old girl with an initially misdiagnosed (“keratocystic”) lesion who presented with recurrent intraoral bleeding, swelling, and tooth loosening of the right mandible. Magnetic resonance and angiographic imaging revealed an extensive intraosseous mandibular AVM extending into the peri-mandibular soft tissues, with arteriovenous shunts and a venous aneurysm. Following emergency hemostasis and blood transfusion, a total of five staged interventional radiological embolization procedures were performed between 2023 and 2024. Acute bleeding episodes could be controlled; however, sustained remission was not achieved. During the course of treatment, the patient developed a submandibular abscess and post-traumatic stress disorder (PTSD). Histopathological examination demonstrated a vascular malformation without evidence of malignancy. Molecular genetic testing identified a somatic KRAS (Kirsten rat sarcoma virus) mutation. Due to insufficient response to interventional therapy, systemic treatment with the MEK (mitogen-activated protein kinase) inhibitor trametinib was initiated to facilitate future surgical resection. Under this therapy, marked clinical and radiological improvement was observed with good tolerability. This case (3-year observation period) highlights the diagnostic risk of misinterpreting an osteolytic lesion, the importance of early diagnosis, the interdisciplinary staged and combined approach, the potential of molecular targeted therapy with an MEK inhibitor in treatment-refractory pediatric mandibular AVMs, and the continued relevance of surgical treatment strategies. These findings should be interpreted with appropriate caution and require validation in prospective studies.