[Peripheral ameloblastoma of the maxilla: report of a case].

A case of peripheral ameloblastoma is presented which was located in the right maxillary tuberosity area in a 52-year-old caucasian male. The lesion was asymptomatic and presented as a reddish sessile mass of soft tissue, 1.5 cm in diameter, with a granular surface and firm texture (Fig. 1). There was no radiologic evidence of bone involvement (Fig. 2). A clinical diagnosis of squamous cell carcinoma was made and a biopsy was taken. The microscopical examination revealed the presence of ameloblastomatous tissue exhibiting numerous areas of continuity with the surface epithelium (Fig. 3). The tumor showed a mixed follicular (Fig. 4) and plexiform (Fig. 5) pattern and was accompanied by a mild lymphocytic infiltrate (Fig. 3). A partial maxillectomy was performed and the histopathological examination of the surgical specimen confirmed the diagnosis of peripheral ameloblastoma. A primary basaloid pattern of the tumor was identified (Fig. 6) but a search for acanthomatous areas was proved fruitless. Some epithelial islands showed peripheral columnar cells with apically polarized nuclei (Fig. 7). The space between the border of the tumor (Fig. 8) and the underlying bone was filled with dense connective tissue and contained two isolated tumor follicles with cystic change (Fig. 9). The thorough examination of the co-existed bone did not reveal any areas of tumor invasion. Finally, the oral epithelium adjacent to the tumor exhibited elongated and slender rete ridges (Fig. 10). One and a half year post-operatively, no signs of recurrence could be detected.