Intraosseous Arteriovenous Malformation of the Mandible Presenting as Progressive Posterior Mandibular Swelling: A Case Report

Abstract

Background: Intraosseous arteriovenous malformations (AVMs) of the mandible are rare high-flow vascular lesions that may present with progressive swelling, tooth mobility, cortical expansion, or bleeding. Their clinical and radiographic features can resemble odontogenic cysts and tumours, creating a risk of severe haemorrhage if biopsy or extraction is undertaken before the vascular nature of the lesion is recognised. Early identification and appropriate vascular assessment are therefore essential for safe diagnosis and treatment planning. Aims: To describe the clinical and cone-beam computed tomography (CBCT) features of AVM presenting as progressive jaw swelling and to emphasise the need to recognise vascular lesions before invasive dental procedures. Presentation of Case: A 55-year-old man presented with a one-year history of progressive swelling of the right posterior mandible, mobility of the mandibular right posterior teeth, and subsequent tooth loss. Clinical examination showed facial asymmetry and a firm mandibular swelling. CBCT revealed a well-defined expansile osteolytic lesion with coarse radiating trabeculae, cortical thinning, and focal cortical discontinuity. Incisional biopsy specimens from the right mandible showed multiple large, thick-walled blood vessels, some containing blood, within mature bony trabeculae. The histopathological impression was suggestive of a vascular malformation. Correlation of the clinical, imaging, vascular, and histopathological findings supported the diagnosis of mandibular intraosseous arteriovenous malformation. Discussion: Mandibular AVMs are uncommon high-flow vascular malformations that may present with swelling, tooth mobility, pain, cortical expansion, or bleeding. Their radiographic appearance may overlap with odontogenic cysts and tumours. CBCT defines osseous extent and cortical integrity, whereas contrast-enhanced vascular imaging and angiography are needed for haemodynamic assessment and treatment planning. Conclusion: A vascular lesion should be considered in an unexplained expansile mandibular lesion, particularly when swelling is accompanied by tooth mobility. Biopsy or extraction should be deferred until vascularity has been assessed because manipulation may cause severe haemorrhage. Multidisciplinary management commonly includes embolisation with or without surgery.