Maxillary Ameloblastoma: A Review With Clinical, Histological and Prognostic Data of a Rare Tumor

Abstract

Diagnosis of odontogenic tumors can be challenging due to their rarity and diverse morphology, but when arising near the tooth, the diagnosis could be suspected. When their location is not typical, like inside the paranasal sinuses, the diagnosis is less easy. Maxillary ameloblastomas are exceedingly rare with only sparse information on their epidemiological, histological and genetic characteristics. The aim of this report is to thoroughly review the available literature in order to present the characteristics of this tumor. According to available data, maxillary ameloblastomas can occur in all ages but later than mandible ones, and everywhere within the maxillary region without necessarily having direct contact with the teeth. No sex preference has been shown. The most common histological patterns seen in this location are the follicular and plexiform ones. Maxillary ameloblastomas are locally aggressive neoplasms, thus therapy aims for excision including normal bone beyond the lesion. In contrast to mandible ameloblastomas, maxillary ones most commonly show mutations of the SMO gene. Furthermore, differential tumor diagnosis is thoroughly discussed in the present review. Odontogenic tumors are rare and can pose diagnostic difficulties for non-specialized pathologists. Nevertheless, when the location is typical, i.e. molar region and when the histology shows the characteristic features of odontogenic neoplasms, diagnosis could be straightforward. In locations outside the oral cavity or when rare histological variants are found, suspecting the correct diagnosis can be challenging. This is especially true for maxillary ameloblastomas, which are rare, possibly leading to low awareness of this neoplasm at this location and often show non-classical morphology, thus, rendering its diagnosis more complicated. Thus, the aim of this review is to define and thoroughly describe maxillary ameloblastomas based on the available literature after a short introduction in the entity of ameloblastoma.

The controversial role of MDM2, MCM3 and Bcl-X in Ameloblastoma and Ameloblastic Carcinoma: An update

“…Odontogenic tumors are a diverse group of osteo-destructive lesions with a wide range of clinical and biological characteristics. Diagnosis of odontogenic tumors can be challenging due to their rarity and diverse morphology [18][19][20] In view of this fact, a growing number of studies have tried to identify epithelial and mesenchymal factors that participate in the regulation of their growth and determine the differences in behavior between these diseases. The rarity of malignant odontogenic tumors, variations in their pathogenesis and biological behavior all contribute to the difficulty in diagnosing them.…”

“…Moreover, it may be difficult to distinguish some of these tumors from their benign counterparts and verifying their odontogenic origin can be challenging at times. The most obvious characteristics of malignant tumors are proliferation and migration [18][19][20] .…”

Metastatic ameloblastoma: Cytologic diagnosis of a rare entity

“…Lung is considered the most common site of metastasis at a rate of approximately 75%–88%, which develops through hematogenous and lymphatic spread with few metastases within bronchi and bronchioles occurring due to aspiration 5 . Immunohistochemically, almost all ameloblastomas are positive CK19 which is a nonspecific marker for odontogenic epithelium, CK5 and P63 markers of oral epithelium, CK13 and calretinin are positive in stellate reticulum cells, while the peripheral cells stain for CK14 and CD56 6 …”

Odontogenic Cysts and Tumors of Maxilla and Maxillary Sinus (A Clinicopathological Analysis)

“…Although maxillary ameloblastomas are rare compared to those of the mandible; they still ranked high among OGTS in this study. This tumor is aggressive, usually showing extensive extension into the adjacent structures such as nasal cavity and maxillary sinus, (19) and can clinically mimic a sinonasal malignancy. Ameloblastoma can arise primary from the surface epithelium of the maxillary sinus; however, such a diagnosis is rare and can't be made without excluding an extension from the surrounding maxillary bone first.…”