Extraosseous Arteriovenous Malformation of the Submandibular Space Managed With Preoperative Bleomycin-Polidocanol Sclerotherapy and Submandibular Gland-Preserving Excision: A Case Report

Arteriovenous malformations (AVMs) confined to the submandibular space, without mandibular or intraosseous involvement, are exceptionally rare and can closely mimic salivary gland neoplasms.Unplanned biopsy or surgery of an unrecognized AVM carries a risk of serious hemorrhage.We report a 17-year-old female who presented with a slowly enlarging, painless, right submandibular swelling of 10 months' duration.Color Doppler ultrasonography suggested a vascular lesion, and contrastenhanced magnetic resonance imaging (MRI) with MR angiography confirmed a high-flow extraosseous AVM supplied by the facial artery and its submental branch, arising from the right external carotid artery, closely adherent to the inferior surface of the mandibular body without cortical erosion.Fine needle aspiration was deferred.Preoperative intralesional sclerotherapy with bleomycin (15 IU) and polidocanol, delivered by direct percutaneous puncture, produced a mild reduction in lesion size and reduced internal vascularity on Doppler, with a few persistent vascular channels.Complete excision was performed two weeks later through a submandibular skin crease incision, with minimal blood loss of 15 mL.The submandibular gland was identified as a separate, intact structure and preserved.Histopathology confirmed an AVM with direct arteriovenous communications and stromal fibrosis consistent with sclerotherapy effect.At 10 months of clinical follow-up, there was no evidence of recurrence, with preserved marginal mandibular, lingual, and hypoglossal nerve function and clinically normal salivary flow from the preserved gland.To our knowledge, an extraosseous AVM of the submandibular space managed with preoperative bleomycinpolidocanol sclerotherapy followed by gland-preserving surgical excision has not been previously reported.The case underlines the need for imaging before biopsy of a submandibular mass and suggests that glandsparing excision may be feasible when the lesion does not involve the glandular parenchyma and imaging shows a clear plane between the lesion and the gland.