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

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.