Odontogenic Cutaneous Fistula-Induced Submandibular Abscess in a Dog: A Rare Presentation

Abstract

Simple Summary Odontogenic cutaneous fistulas usually develop from maxillary periapical infections that drain externally through the facial skin. Mandibular odontogenic cutaneous fistulas are not common because of the thick mandibular cortex and limited drainage pathways. We describe the case of a 14-year-old male mixed-breed dog that had a chronic periapical infection of the right mandibular first molar tooth that penetrated the mandibular bone and extended into the submandibular soft tissues, which formed a draining fistulous tract. The lesion was initially misdiagnosed as a salivary gland cyst. However, computed tomography confirmed a fistulous connection between the mandibular apex and the subcutaneous lesion. Surgical removal of the affected tooth and tract achieved complete resolution. This case emphasizes that mandibular odontogenic cutaneous fistulas can mimic submandibular abscesses and highlights the importance of using cross-sectional imaging and individualized surgical management for accurate diagnosis and treatment.Abstract Odontogenic cutaneous fistulas (OCFs) are relatively uncommon in veterinary patients. They are typically caused by chronic periapical infections of the maxillary teeth. Mandibular OCFs that extend through the cortical bone into submandibular soft tissues are extremely rare. This report describes the case of a 14-year-old male mixed-breed dog that presented with a submandibular cutaneous lesion initially misdiagnosed as a salivary mucocele. OCFs are frequently misdiagnosed because atypical presentations may lack obvious intraoral abnormalities and mimic salivary gland disease, lymphadenopathy, or cutaneous neoplasia. Computed tomography (CT) revealed a periapical lesion associated with the right mandibular first molar, cortical bone lysis, and extension into the adjacent submandibular tissues, which formed an external fistulous tract. Surgical management included extraction of the affected tooth, resection of the fistulous tract, and excision of the associated lymph nodes, which resulted in a complete and uneventful resolution of the fistula. At the 3-month follow-up, the patient remained clinically stable without evidence of recurrence. This case underscores the clinical pearl that odontogenic origins should always be considered in the differential diagnosis of submandibular or cervical cutaneous lesions and that cross-sectional imaging modalities, such as CT, are indispensable for confirming anatomical continuity and guiding surgical planning.