Sinonasal Ameloblastoma

Abstract

Ameloblastomas are benign but aggressive odontogenic tumors that most commonly affect the posterior mandible. Approximately 15% occur in the maxilla, with a subset thought to originate from the epithelial lining of the sinonasal cavities. Histologically, sinonasal ameloblastomas are identical to those of the oral cavity, with classical features of palisaded columnar basilar cells surrounding a central proliferation that resembles the stellate reticulum of a developing tooth. Unlike the gnathic variant, sinonasal ameloblastomas tend to affect males more than females, and the incidence of diagnosis peaks at a later age, approximately 60 years old. The overall prognosis is favorable, with local recurrence being the most common long-term sequalae.

Keywords: Gnathic; Maxilla; Odontogenic neoplasm; Sinonasal ameloblastoma.

Fig. 1

3D volume rendering (upper left), axial (upper right), coronal (lower left), and sagittal (lower right) CT images without contrast. Red outline indicates the peripheral borders of the lesion. Red arrows indicate involvement of the left orbit and left cranial base

Fig. 2

Varying histologic patterns of ameloblastoma are appreciated at low power

Fig. 3

An area of plexiform pattern demonstrating anastomosing cords of ameloblastic epithelium (high power)

Fig. 4

An area demonstrating the follicular pattern. Reverse polarization and subnuclear vacuolization of the basal layer are appreciated (high power)

Fig. 5

Follicular and acanthomatous patterns dispersed within the same neoplasm (medium power)