Aim: To present a case report describing the diagnosis and treatment of an extraoral cutaneous sinus tract of odontogenic origin in relation to a mandibular left central incisor. Summary: The extraoral cutaneous sinus tract of dental origin is an uncommon, but well-documented condition. However, several non-odontogenic disorders may also cause an extraoral sinus tract. The diagnosis is not always easy unless the treating clinician considers the odontogenic origin. The present case report discusses diagnosis and treatment of an extraoral cutaneous sinus tract of odontogenic origin in relation to a mandibular left central incisor (diagnosed as asymptomatic suppurative periradicular periodontitis with an extraoral cutaneous sinus tract opening in the mandibular mental region). Non-surgical endodontic therapy was performed under oral antibiotic therapy. During instrumentation, a nickel-titanium rotary file became separated in the middle and apical third of the canal, thus making the case more challenging. The instrument was retrieved with the use of an ultrasonic tip. The patient responded well, and the cutaneous lesions healed uneventfully. Schlagwörter: extraoral cutaneous tract, non-surgical endodontic treatment, separated endodontic files, ultrasonic tips