A Unilocular Radiolucency of the Anterior Maxilla

Oral Findings

On clinical examination, slight labial cortical bone expansion was palpable overlying the lesion. Pulp testing indicated all teeth in the area were vital.

Radiographic Findings

A periapical radiograph revealed a well-circumscribed, round, 1 x 1 cm radiolucency between the roots of the maxillary right canine and lateral incisor (Figure 1). The lesion exhibited a sclerotic border, and no obvious central calcifications could be identified.
radiolucency between roots
Figure 1. A well-circumscribed unilocular radiolucency between the roots of the maxillary right canine and lateral incisor.
Excisional Biopsy and Photomicrographs

A biopsy of the mass was performed under local anesthesia. After reflection of a buccal flap, the cortical plate appeared slightly expanded and thinned. The cortical bone was removed, and a solid soft tissue mass was easily curetted from the bony cavity. Multiple irregular fragments of soft tissue were submitted for microscopic examination.

The tissue sections showed an epithelial proliferation exhibiting a variable microscopic pattern. At low power, the lesion showed solid, nodular masses of basophilic cells intermixed with less cellular areas (Figures 2 and 3).
lesion with basophilic cells
Figure 2. Low-power scanning photomicrograph of one portion of the lesion showing nodular groups of basophilic cells (Hematoxylin and eosin stain).
nodular groups of epithelial cells
Figure 3. Medium-power photomicrograph showing nodular groups of epithelial cells intermixed with looser ribbon-like strands (Hematoxylin and eosin stain).
The epithelium in the solid zones consisted of small, tightly packed polygonal to spindle-shaped cells. The less cellular areas were characterized by ribbon-like cords of basophilic cells with little background stroma.

A characteristic finding in the solid zones was the presence of occasional duct-like structures lined by a row of cuboidal to columnar epithelial cells (Figures 4 and 5).
duct-like structure in cells
Figure 4. Medium-power photomicrograph showing a duct-like structure in the upper left corner of the image (Hematoxylin and eosin stain).
multiple small duct-like structures
Figure 5. High-power photomicrograph showing multiple small duct-like structures surrounded by cuboidal epithelial cells (arrows) (Hematoxylin and eosin stain).
In addition, focal dystrophic calcifications were present, sometimes being found in association with slightly larger, eosinophilic cells exhibiting a squamoid appearance (Figure 6).
small dystrophic calcifications
Figure 6. Medium-power photomicrograph showing small dystrophic calcifications in association with squamoid cells (Hematoxylin and eosin stain).