Photo Quiz

A Painless Facial Nodule


Am Fam Physician. 2018 Sep 1;98(5):317-318.

A 19-year-old man with autism presented with a solitary erythematous nodule on his chin that had been present for three months. The patient's mother thought the lesion was not particularly painful or pruritic, but she occasionally noticed him picking at the spot. They had not noticed any drainage. He had no fever or chills, and no history of dental or oral symptoms. He had no other lesions. He was prescribed a 10-day course of oral clindamycin, which reduced the size of the lesion. However, the lesion persisted.

Physical examination revealed a cluster of two 2- to 4-mm, erythematous, crusted, dome-shaped papules situated within a dimpling on the patient's lateral chin (Figure 1). On palpation, the area was slightly indurated, and the lesions seemed fixed and immobile when the surrounding skin was manipulated. There was no fluctuance or discharge. On palpation of the buccal mucosa, an indurated subcutaneous cord was appreciated emanating from the lesion and tracking down to the angle of the mandible.

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Based on the patient's history and physical examination findings, which one of the following is the most appropriate next step?

A. Perform punch biopsy of the erythematous lesion.

B. Prescribe a 10-day course of oral trimethoprim/sulfamethoxazole.

C. Prescribe a course of topical salicylic acid 17% solution.

D. Prescribe topical benzoyl peroxide 5% wash and tretinoin 0.05% cream (Retin-A).

E. Refer the patient for oral imaging and dental examination.


The correct answer is E: refer the patient for oral imaging and dental examination. A panoramic radiograph showed a well-defined periapical radiolucency around the distal root of the tooth, consistent with an abscess (Figure 2). An orocutaneous fistula may also be known as a dental sinus, periapical abscess with sinus, or odontogenic cutaneous sinus tract. It occurs when a tract forms between the skin surface and an infection within the oral cavity. It is rare and can be misdiagnosed and ineffectively treated with antibiotics or surgical procedures.1

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Address correspondence to J. Thomas Landers, MD, at Reprints are not available from the authors.

Author disclosure: No relevant financial affiliations.


show all references

1. Sato T, Suenaga H, Igarashi M, Hoshi K, Takato T. Rare case of external dental fistula of the submental region misdiagnosed as inverted follicular keratosis and thyroglossal duct cyst. Int J Surg Case Rep. 2015;16:39–43....

2. Lee EY, Kang JY, Kim KW, Choi KH, Yoon TY, Lee JY. Clinical characteristics of odontogenic cutaneous fistulas. Ann Dermatol. 2016;28(4):417–421.

3. Held JL, Yunakov MJ, Barber RJ, Grossman ME. Cutaneous sinus of dental origin: a diagnosis requiring clinical and radiologic correlation. Cutis. 1989;43(1):22–24.

4. Cantatore JL, Klein PA, Lieblich LM. Cutaneous dental sinus tract, a common misdiagnosis: a case report and review of the literature. Cutis. 2002;70(5):264–267.

5. Chen K, Liang Y, Xiong H. Diagnosis and treatment of odontogenic cutaneous sinus tracts in an 11-year-old boy: a case report. Medicine (Baltimore). 2016;95(20):3662.

This series is coordinated by John E. Delzell Jr., MD, MSPH, Associate Medical Editor.

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