교신저자：이준규, 519-809 전남 화순군 화순읍 일심리 160  화순전남대학교병원 이비인후-두경부외과학교실
교신저자：전화：(061) 379-8190 · 전송：(061) 379-7758 · E-mail：joonkyoo@chonnam.ac.kr

Introduction

   Chronically draining cutaneous sinus tracts are frequently misdiagnosed and incorrectly treated. Diagnostic errors can result in multiple surgical excisions and biopsies, long-term antibiotic therapy, and even radiation therapy or electrodessication. The primary odontogenic disorder that results in such cutaneous lesions is typically a chronic apical abscess.^1,2) A sinus tract from a mandibular osteomyelitis is very rare and hard to detect. This is the first case of a cutaneous submandibular draining sinus tract that developed from a mandibular osteomyelitis unrelated to a tooth inflammation.

Case

   A 36-year-old woman was transferred to our hospital with a 1.5 year history of purulent discharge from a cutaneous sinus present at the submandibular region. The medical history was noncontributory. The patient was a social drinker but not a smoker. She denied fever, chills, weight loss, recent symptoms related to an upper respiratory tract infection, or dental problem. The patient had three excision and drainage procedures before presenting to the hospital with a recurrence.
   The head and neck examination revealed an elevated draining outlet of 1 cm diameter with an erythematous base on the skin of the neck 2 cm below the left mandibular body (Fig. 1A). The lesion did not cause any significant pain or tenderness. There was no swelling over the mandible. The intraoral findings were noncontributory. The neck computed tomography revealed a 1.1 cm well-defined tubular ring enhancing lesion from the subcutaneous layer to the skin of the left upper neck (Fig. 1B). There was a part of the sinus tract under the mandible which was connected to the skin (Fig. 1C). A focal disruption of 10×2.5 mm with radiolucence on the posterior surface of the left inferior mandibular body was noted (Fig. 1D). Thorough examination of the teeth by a dentist was within normal limits.
   Surgery was performed; the cutaneous part of the sinus tract was resected and dissected along the tract to the submandibular space. The tract was connected to the posteroinferior border of the mandible. A moth-eaten lesion on the cortex of mandible was detected. A thorough debridement of the lesion with a curette was performed. The pathology revealed granulation tissue with suppurative inflammation. The microbiology was negative for the cultures of the surgical biopsy specimens. Antibiotics were started empirically with amoxicillinclavulanate (Augmentin^®) was administered intravenously for 5 days and per oral for 7 days. There were no complications related to the surgery.
   The patient was discharged from the hospital and followed for eight months without any sign of recurrence or complications.

Discussion

   An extraoral sinus tract, of dental origin, may be confused with a wide variety of disorders including local skin infections, ingrown hairs, occluded sweat gland ducts, neoplasms, tuberculosis, actinomycosis, and a congenital midline sinus of the upper lip.^{3,4,5,6,7,8,9)} The possible dental causes include trauma, retained roots, residual chronic infection of the jaw, and pulp abnormalities.^1,2,10,11) 
   Yeoh at al. recently reported the case of a draining sinus from a chronic suppurative osteomyelitis of the mandible.¹²⁾ However, that case, with osteomyelitis was complicated by a retained tooth root. In this study, on the other hand, the osteomyelitis was located focally at the inferior part of the posterior mandible and not connected to any of the roots of the teeth. The etiology of the osteomyelitis of the mandible was unknown. Cases with osteomyelitis of the jaw can be attributed to one or more predisposing factors including the following: 1) noncompliant patients refractory to health care delivery, 2) systemic, metabolically compromised individuals (age of patient, malnutrition, immunosuppression, or congenital or acquired pathophysiology disrupting microvascular perfusion of calcified tissue structures and investing soft tissue envelope), and 3) inaccessibility to health care delivery.¹³⁾ Therefore, different from many of the previously reported cases, osteomyelitis of the mandible can occur in an uncompromised healthy population and a draining sinus from the osteomyelitis in such patients should be added to the list of abnormalities associated with this infection.
   Clinicians should recognize that the most common cause of a chronic cutaneous sinus tract, in the face and neck region, is a chronically draining dental infection. The location of the sinus tract opening does not necessarily indicate the origin of the inflammatory exudates. Patients with the origin of the sinus tract incorrectly diagnosed undergo unnecessary surgical procedures and antibiotic therapy, as did the patient presented here. This case was finally managed successfully with appropriate surgical debridement at the source of the inflammation.

Conclusion

   A cutaneous draining sinus from an osteomyelitis of the mandible should be included in the differential diagnosis of chronic draining sinus in similar patients.

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