Mixed Breed Case

Species: CANINE
Breed: Mixed Breed
Age: 6y
Gender: FEMALE, SPAYED

Source/History: 

Gingival growth slowly enlarging over one year. No bone involvement up on x-ray.

Low magnification view of the lesion (as submitted), demonstrating gingival growth.

Medium magnification view of the lesion (20X), demonstrating epithelial and mesenchymal components.

Low magnification view of the lesion (5X), demonstrating osseo-cementous material amidst proliferative periodontal ligament.

Click here for the IDEXX Pathology Report on this case.

Microscopic Description:

This section of gingiva is characterized by proliferation of the stratified squamous epithelium. Coalescing islands and cords of epithelial cells extend into the underlying periodontal ligament connective tissue. The epithelium is comprised of cords and lobules of polygonal epithelial cells with prominent intercellular bridges, eosinophilic cytoplasm and round to oval nuclei with a prominent nucleolus. Mitotic figures are rarely observed. The peripheral cells palisade around these polygonal cells. The surrounding stroma is comprised of spindloid cells with indistinct cytoplasmic margins, eosinophilic cytoplasm and oval to stellate-shaped nuclei with a stippled chromatin pattern. The proliferative tissue extends to the surgical margins. Low to moderate numbers of lymphocytes, plasma cells and occasional neutrophils are scattered throughout the sample, especially in the subepithelial areas.

Interpretation:

Gingiva: Acanthomatous ameloblastoma, extends to margins with mild lymphoplasmacytic gingivitis.

Excision:

Extends to margins.

Comments:

Acanthomatous ameloblastoma (previously named acanthomatous epulis) is a locally aggressive neoplasm derived from ameloblastic cells and often behaves like a squamous cell carcinoma. It may extensively infiltrate the underlying bone, although it has not been reported to metastasize via lymphatics to regional lymph nodes.

References:

Pathology of Domestic Animals, 5th Ed., Vol. 2, pp. 25-26, 2007

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