This 33 year-old female presented with a slowly growing cystic mass in the left superior gingivolabial angle above the lateral incisor.
This axial CT scan image shows a well circumscribed round bony erosion (asterisk) corresponding to the ovoid cystic mass in the anterior surface of the premaxilla. The mass bulges slightly into the floor of the left nasal vestibule.
Surgical picture showing the resection of the nasolabial cyst was via a small incision in the upper gingivolabial sulcus.
H & E photomicrograph of the above fissural maxillary cyst. This section shows fibrous tissue with abundant cholesterol clefts, with histiocytes or xanthomatous cells as well as chronic inflammatory cells, consisting of lymphocyes, plasma cells and eosinophils.
(Note the similarity of the cholesterol clefts to those seen in a cholesterol granulomas of the ear or petrous apex)
Jaw cysts are broadly defined as an epithelial-lined space within bone.
They are classified as being either nonodontogenic (fissural), such as nasopalatine duct cysts, median palatal cysts, globulomaxillary cysts, and nasolabial cysts; or, odontogenic, such as apical cysts, dentigerous cysts, primordial cysts, odontogenic keratocysts, and residual cysts.
Odontogenic and nonodontogenic cysts are distinguished based on the ontogeny of the epithelium rests from which the cysts are thought to derive, with odontogenic jaw cysts arising from tooth development epithelium, and nonodontogenic jaw cysts arising from epithelium trapped during the fusion of upper jaw bones during embryonic development at sites of fissures.
Nonodontogenic jaw cysts may be further differentiated from one another based on anatomic location: nasopalatine duct cyst (incisural canal), medial palatal cyst (midline of hard palate), globulomaxillary cyst (between premaxilla and maxilla) and nasolabial cysts (along side of nose). Of note, some authors have stopped distinguishing nasopalatine duct cysts from medial palatal cysts, arguing that medial palatal cysts are merely more posterior manifestations of a nasopalatine duct cyst.