A soft tissue swelling lies LATERAL to the midline in the anterior maxilla, elevating the ala of the nose and the upper lip. There is no bony change on radiographs. What is the most likely diagnosis?

Correct answer: B. Nasolabial cyst

• A. The globulomaxillary lesion is intraosseous, appearing as an inverted pear-shaped radiolucency between the lateral incisor and canine. It is no longer regarded as a distinct entity — most such lesions prove to be odontogenic cysts or tumors on biopsy.
• B. CORRECT. The NASOLABIAL (nasoalveolar, Klestadt) cyst is a rare NON-ODONTOGENIC developmental cyst of SOFT TISSUE that sits in the upper lip and nasolabial fold, lateral to the midline, over the canine eminence. Because it is entirely extraosseous it produces NO radiographic change unless it has been present long enough to cause pressure resorption of the underlying cortex. It classically obliterates the nasolabial fold, elevates the ala of the nose, and raises the upper lip — often only appreciated by lifting the lip and palpating bimanually. Treatment is surgical enucleation via an intraoral sublabial approach.
• C. The nasopalatine duct cyst is INTRAOSSEOUS and MIDLINE, arising in the incisive canal and producing the classic heart-shaped or oval radiolucency between and apical to the maxillary central incisors. The stem specifies a lateral, soft tissue lesion with no bony change.
• D. A mucocele results from severed minor salivary gland duct and is overwhelmingly a LOWER LIP lesion in young people, presenting as a fluctuant bluish swelling. Upper lip mucoceles are uncommon and should raise suspicion of a salivary gland neoplasm.

Note: Non-odontogenic cysts of the maxilla, by location: MIDLINE intraosseous = nasopalatine duct cyst. LATERAL soft tissue = nasolabial cyst. Midpalatal in infants = median palatal cyst.