Amyloid-producing odontogenic tumor in a Shih-Tzu dog

A 9-month-old male Shih-Tzu dog had a right mandibular tumor composed of strands, or nest-like proliferation of epithelial cells with abundant fibrous stroma characterized by spheroid to large nodular deposition of amyloid with Congo-red stain. Globule calcification was also seen throughout the tumor tissue and the spheroid depositions often had a concentrically laminated structure (Liesegang rings). The case was diagnosed as amyloid-producing odontogenic tumor in a dog.