Oral Masses in Two Cats

Abstract

Incisional biopsies from the oral cavity of 2 adult cats were submitted for histological investigation. Cat No. 1 showed a solitary well-circumscribed neoplasm in the left mandible. Cat No. 2 demonstrated a diffusely infiltrating neoplasm in the left maxilla. Both tumors consisted of medium-size epithelial cells embedded in a fibrovascular stroma. The mitotic index was 0 to 1 mitosis per high-power field. The epithelial cells showed an irregular arrangement forming nests or streams in cat No. 1, whereas a palisading growth was noted in cat No. 2. Both tumors, especially that of cat No. 1, showed multifocal accumulations of amyloid as confirmed by Congo red staining and a distinct green birefringence under polarized light, which lacked cytokeratin immunoreactivity as well as and AL and AA amyloid immunoreactivity. In addition, the amyloid in cat No. 2 was positive for the odontogenic ameloblast-associated protein, formerly termed APin. In sum, both cats suffered from an amyloid-producing odontogenic tumor, but their tumors varied with respect to morphology and type of amyloid produced.

Amyloid-Producing Odontogenic Tumors of the Facial Skin in Three Cats

“…1,2,9 Positive signals of pan-CK, AE1/AE3, CK14, and CK19 were always detected in the cytoplasm with variable intensity. 1,2,9 However, vimentin, laminin, GFAP, S100, calretinin, and ODAM were not detected in all feline APOTs. 1,2,9 Also, positive signals of nerve growth factor receptor were found in the neoplastic cells of 2 out of 3 cats.…”

“…2,9 Therefore, these proteins are not considered to be precursors of amyloid materials, at least in feline APOTs. 1,2,9 Immunohistochemical characterization of the neoplastic epithelial cells of feline APOTs has been performed in a few studies. 1,2,9 Positive signals of pan-CK, AE1/AE3, CK14, and CK19 were always detected in the cytoplasm with variable intensity.…”

“…1,2,9 Immunohistochemical characterization of the neoplastic epithelial cells of feline APOTs has been performed in a few studies. 1,2,9 Positive signals of pan-CK, AE1/AE3, CK14, and CK19 were always detected in the cytoplasm with variable intensity. 1,2,9 However, vimentin, laminin, GFAP, S100, calretinin, and ODAM were not detected in all feline APOTs.…”

Immunohistochemical and Biochemical Evidence of Ameloblastic Origin of Amyloid-Producing Odontogenic Tumors in Cats

“…Though rare, APOTs have been documented in dogs, cats, and a Bengal tiger. 1,3,5,6 Most APOTs are expansile, solid, or cystic masses of the mandibular or maxillary gingiva. APOTs are typically benign but can invade locally, incorporate teeth, and even destroy jaw and facial bones.…”

Nomenclature and Classification of Odontogenic Tumors — Part II: Clarification of Specific Nomenclature

“…Three papers have since reported additional cases of APOT in dogs and cats. [30][31][32] Yet, a few published reports of CEOT in animals seem to satisfy the criteria for CEOT in humans. 24,25,27,28 Some tumors previously diagnosed as keratinizing ameloblastoma have subsequently been determined to be APOT.…”