LAUSR

A 13yearold girl presented with a 6month history of a recurrent single erythematous nodule on her right cheek associated with periodic drainage of inflammatory exudate. The patient did not have any discomfort or history of trauma or infection. Physical examination revealed a welldefined soft erythematous nodule about 1 cm in diameter in her right mandibular angle (figure 1A). Skin biopsy from the lesion showed nonspecific chronic inflammation (figure 1B). The sagittal T2 STIR MRI images showed that the sinus tract extended from the right mandibular first molar tooth (#46, figure 2A), passed through the muscles into the subcutaneous fat and reached the skin, forming a bulging nodule (figure 2B). The CT scan showed the destruction of the apex of the tooth and the alveolar bone. A diagnosis of odontogenic cutaneous sinus tract (OCST) was confirmed. The patient was referred to the maxillofacial team for root canal therapy and there was no recurrence. OCSTs are rare dermatoses caused by dental infection secondary to pulpal necrosis, nearby caries, chemical irritation or trauma. The most common sites for cutaneous sinuses are the mandibular angles, chin and cheeks. Extraoral lesions may present as nodules, ulcers, abscess or scars. Lesions with minimal or no dental symptoms are easily misdiagnosed as skin infection, pyogenic or foreignbody granulomas, or chronic tuberculosis lesion, leading to delayed treatment. Paediatricians should consider OCST when evaluating a chronic cutaneous sinus of unknown aetiology in the orocervicofacial areas. Root canal therapy can be the first choice for a restorable tooth, but for a nonrestorable tooth, surgical excision may be considered. 3