Odontogenic cutaneous sinus tract associated with a mandibular second molar having a rare distolingual root: a case report.

INTRODUCTION: Odontogenic cutaneous sinus tracts are often misdiagnosed as lesions of non-odontogenic origin, leading to the treatment of patients with unnecessary and ineffective therapies. Sinus tracts of endodontic origin usually respond well to endodontic therapy. However, root canal treatment of mandibular molars with aberrant canal anatomy can be diagnostically and technically challenging. Herein we present a patient with a cutaneous odontogenic sinus tract in the right submandibular area. CASE REPORT: A 23-year-old Chinese female patient presented with a cutaneous odontogenic sinus tract that was initially misdiagnosed as a sebaceous cyst. The patient had undergone surgical excision and traditional Chinese medical therapy before endodontic consultation. With the aid of cone beam computed tomography (CBCT), it was confirmed that the causative factor of the cutaneous odontogenic sinus tract was chronic periapical periodontitis of the right mandibular second molar, which had a rare and curved distolingual root. The resolution of the sinus tract and apical healing was accomplished following nonsurgical root canal treatment. CONCLUSION: A dental aetiology must be included in the differential diagnosis of cutaneous sinus tracts in the neck and face. Elimination of odontogenic cutaneous sinus tract infection by endodontic therapy results in resolution of the sinus tract without surgical excision or systemic antibiotic therapy. This case report also indicates that CBCT imaging is useful for identifying the tooth involved, ascertaining the extent of surrounding bone destruction and accurately managing the aberrant canal morphology.