Is Ultrasonography Useful in the Diagnosis of Nasolabial Cyst?

Nasolabial cysts are nonodontogenic cysts that occur beneath the ala nasi. Its pathogenesis is uncertain. Because the nasolabial cyst is a soft tissue lesion, plain radiographs are useless. CT and MRI should be evaluated. In this report, a nasolabial cyst is described including its features on ultrasonography (USG) and CT exams. 1. Introduction Nasolabial cysts are rare nonodontogenic cysts located adjacent to the alveolar process above the apices of incisors [1] and firstly described by Zuckerlandl in 1882 [2]. The term “nasoalveolar cysts” is also used. Clinical properties of nasolabial cysts are usually typical. They can be observed as painless, fluctuating unilateral swellings, at the left alar region. Rarely they can be observed bilaterally. Infection of the cyst may cause pain, and it can drain into the nasal cavity [1]. Because nasolabial cysts are generally not found in the bone tissue, conventional radiographies are not helpful in diagnosis. Instead, other imaging methods such as CT and MRI should be used for diagnosis. USG is a diagnostic method that is often used for examination of soft tissue lesions and it can also be used in the maxillofacial region. Nasolabial cyst is a lesion of the soft tissue and it can be diagnosed with USG. In this case, CT and USG diagnosis have shown the presence of a 1.5？cm diameter cystic lesion in the soft tissue which has been diagnosed as nasolabial cyst in the histopathologic examination. 2. Case Report A 38-year-old woman presented with a 5-year history of an increasing left nasal ala area swelling. She mentioned difficulty in breathing for about 3 months. She was suffering from pain in nasolabial fold for about 1 year. There was no history of trauma and no medical history. Clinical examination revealed a smooth and fluctuant mass in the left nasal ala area. A floating tumefaction in the nasolabial sulcus was observed. Intraoral examination revealed bulging of the buccoalveolar sulcus by the swelling. There was a facial asymmetry due to bulge on the left side of the nose. The associated teeth tested vital with electrical vitality testing. Nasolabial cysts generally do not cause bone destruction, but in this case bone destruction was observed on panoramic radiograph (Figure 1) and CT image (Figure 2). USG image showed well-defined cystic lesion with 1.5？cm diameter under the skin in left nasolabial fold (Figure 3). After clinical and radiographic examination, the lesion was thought to be a nasolabial cyst. The lesion was removed intraorally under local anaesthesia and it was sent for histopathological