Oral Cutaneous Fistulas Differential Diagnoses

Updated: Mar 03, 2022
  • Author: James E Cade, DDS, FACD; Chief Editor: William D James, MD  more...
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Diagnostic Considerations

The differential diagnoses include any dental and periodontal infection, odontogenic cysts and tumors, salivary gland lesions and neoplasms, and other benign and malignant neoplasms. The most common neoplastic cause of oral cutaneous fistulas is squamous cell carcinoma. Unless secondarily infected, oral cutaneous fistulas rarely, if ever, develop from benign neoplasms and cysts.

Because oral cutaneous fistulas are not common, misdiagnosis of those from a dental origin is not unusual. Several cases below illustrate this.

Dental infections may also mimic dermatologic infections. [39] An example of this was a lesion diagnosed clinically as a sebaceous cyst. Using cone-beam CT, the lesion was discovered to be a cutaneous odontogenic sinus tract from an aberrant formed canal caused by periapical periodontitis of the right mandibular second molar. Root canal therapy was performed, which eliminated the infection. [34]

Two cases of recurrent suppurative oral cutaneous fistulas were misdiagnosed and treated with oral antibiotics without response. One of the lesions was thought to be a pyogenic granuloma and the other a cutaneous furuncle. Both patients were treated with antibiotics without success because the odontogenic or dental cause was not discovered initially. Clinical findings included palpable facial nodules with drainage and poor dentition with gingivitis. Neither patient had obvious signs or symptoms. Radiographs showed periapical lesions. Both situations presented with nonrestorable teeth and therefore were extracted. [40]

Another case of misdiagnosis is presented. A facial fistula developed 8 years following a dental extraction. It occurred in a 42-year-old female patient not known to have any chronic medical illness. She presented with a submandibular skin fistula and was treated with antibiotics and local creams for 3 months with no improvement. She was later referred to an oral and maxillofacial clinic complaining of recurrent pus discharge from her neck for the past 6 months, with no history of dental pain. Examination showed an extraoral fistula in the left submandibular region with pus discharge upon palpation. Intraoral examination showed no soft tissue abnormalities in this area with all molar teeth missing. Panoramic radiography showed a round radiolucent lesion in the left mandible with a radiopaque area consistent with a remaining root. The cone-beam CT evaluation showed a 1-cm × 1-cm round radiolucent lesion causing displacement of the inferior alveolar canal. The root was previously endodontically treated. The remaining root was removed and the surrounding infected tissue was excised completely, preserving the inferior alveolar nerve. [41]

The following case illustrates another situation that was misdiagnosed because of not considering the infection could be from odontogenic origin. This case report describes an 11-year-old patient with an abscess that was not causing any pain. The draining sinus tract in his left cheek was not originally detected. He was tested for Mycobacterium tuberculosis infection, the results of which were negative. The radiograph showed a periapical radiolucency in tooth number 19, with 3 roots with a large restoration, which was shown radiographically to be in the pulp chamber. The lesion was treated with root canal therapy, and the lesion resolved. This tooth had 3 roots with 4 canals. Accurate diagnosis and treatment and eliminating the source of infection can reduce the incidence of complications and relieve the pain, if symptomatic, of the patient. [42]

Differential Diagnoses