Diseases of buccal cavity & Mucosa

Ishtiaq ahmed

Feed in mouth of cadaver is abnormal except Ruminants

In horses indicate encephalitis, leukoencephalo- malacia, hepatic encephalopathy.

Feed poorly masticated

Bones indicate pica

Foreign body stomatitis in dog occur due to plant fibers, burrs or quills, especially in long hair breeds

Sharp foreign bodies induce laceration, necrotic deep stomatitis

Foreign bodies

Pharyngitis

Glossitis

Gingivitis

Tonsillitis

Superficial (only mucosa involved) or deep (connective tissue involved)

Paraquat, erosive stomatitis, dogs

Dieffenbachia Plant

Actinomyces, Fusobacterium, and spirochetes normal flora

Oral mucosa resistant to infection because Squamous mucosa

Antimicrobial salivary contents e.g. lysozyme

Immunoglobulins e.g. IgA

Rich submucosal vascular network

Inflammatory cells

Superficial stomatitis

Usually involve caudal fauces, gingivitis

often develops in the course of debilitating diseases.

Hyperemia, edema, lymphoid tissue proliferation

Thrus/oral candidiasis occur in dog, foals,pigs

Patchy pale-gray pseudomembranous material on oral mucosa and back of tongue

Stachybotrys alternans causes catarrhal & necrotic stomatis

Catarrhal stomatitis

Vesicles, bullae, erosion Virus e.g. FMD virus, Rinderpest, BVD, MCF produce erosive/ulcerative lesions Bullous immune skin diseases do have oral lesions e.g

pemphigus vulgaris (desmoglein 3, suprabasilar acantholysis, clefts,bullae)

Bullous pemphigoid; Subepidermal blistering/cleft; IgG, IgEagainst basement membrane antigens

Mucous membrane pemphigoid most common. Collagen XVII or laminin-5, and basement membrane- fixed immunoglobulin

Vesicular stomatitides

Feline calicivirus

Erosive and ulcerative stomatitides

Phenylbutazone intoxication in horses may cause oral ulcers

Feline ulcerative stomatitis and glossitis; cause unknown

Feline plasma cell gingivitis-pharyngitis: Raised erythematous, proliferative lesions, plasma cell infiltration, elevated polyclonal serum gamma-globulin level

Oral eosinophilic granuloma, dog, young Siberian Huskies.

Ulcerated raised plaques, yellow exudate, on lateral or ventral surface of tongue

Microscopically foci of collagenolysis, histiocytic granulomatous infiltration, giant cells, eosinophils.

Feline rhinotracheitis and uremia (dirty gray brown)also induce ulcerative stomatitis

Oral necr0bacill0sis

Deep stomatitides

Fusobacterium necrophorum

Necrotizing lesions in upper, lower alimentary tract & liver as well

Occurs as a secondary invader

Endotoxins: leukocidins, hemolysins, and a cytoplasmic toxin

Coagulative necrosis

Calf diphtheria: Necrotizing, ulcerative inflammation of oral cavity, pharynx and necrotizing laryngitis

Trauma, infectious bovine rhinotracheitis, and papularstomatitis are predisposing factors

Fatal in youngs, localized in adults

Early lesions:Large, well-demarcated, yellow-gray, dry areas of necrosis, surrounded by a zone of hyperemia.

Necrotic tissue slightly raised, friable, adherent

Histologically: Necrotic tissue surrounded by vascular reaction, thin rim of leucocytes & encapsulating granulation tissue

Bacteria arranged in long filaments at leading edge of lesion

Aspiration penumonia (due to spread from oral foci), septicemia, pituitary and cerebral abscessation

Fusobacterium necrophorum : Another syndrome in calves with necrotic stomatitis, enteritis, and granulocytopenia

Nonregenerative anemia, leukopenia, neutropenia, hypoproteinemia, and increased fibrinogen levels

Along with characteristic oral lesions marked depletion of lymphoid tissues and necrotic enteritis.

Rapidly spreading Pseudomembranous/gangerenousstomatitis

Normal flora e.g. fusobacteria and spirochetes

Predisposing: Mucosal trauma, debility

Small tattered ulcer of the cheek or gum, spread rapidly

Intensely fetid, necrotic area surrounded by acute inflammatory cells

Noma

Cattle, sheep, and pigs

Stomatitis, glossitis, lymphadenitis, sometimes pyogranulomas in the wall of the forestomachs

Actinobacillus lignieresi

Pyogranulomatous inflammatory loci centered on club colonies containing gram-negative coccobacilli.

Arcanobacterium pyogenes, Actinomyces bovis,Staphylococci, Nocardia may also cause pyogranulomas.

Actinobacillosis

Typically a disease of soft tissue, spreading as a

lymphangitis, lymph nodes

wooden tongue

Grossly: Individual inflammatory focus appear as a nodular, firm, pale, fibrous mass a few millimeters to 1 cm in diameter, containing in the center minute yellow "sulfur" granules, which are the club colonies.

Microscopically: Pyogranuloma, centered on a mass

of coccobacilli, surrounded by radiating eosinophilic clubs made up of immune complexes.

Club colonies surrounded by neutrophils, macrophages, giant cells

Lymphocytes, plasmacytes in surrounding fibrous reactive stroma

Dermatophilus congolensis

Exudative dermatitis in many spp but in cat oral granulomas

Tongue and tonsillar crypt

DDX: SCC

Oral dermatophitosis of cats

Sarcosporidiosis

Cysticercosis

Trichinella spiralis

Gongylonema spp

Gasterophilus spp. in the horse

Oestrus ovis in sheep

Halicephalobus gingivalis

Parasitic diseases of the oral cavity

Prominent and protrude slightly from the tonsillar fossa in the dog and cat.

In horses tonsillar tissues are dispersed over pharyngeal and epiglottic mucosal surfaces

Immune surveillance in the oropharynx

Tonsillitis may occur include pasteurellosis in sheep and pigs, Actinomyces and Tonsillophilus in tonsils of swine, and necrobacillosis in all species

Diseases of the tonsils

Scrapie-associated prion protein in the center of primary and secondary lymphoid follicles

Primary replication site for Pseudorabies (Aujeszky'sdisease)

Involution of B-dependent tonsillar lymphoid follicles due to viral lymphocytolysis in many viral infections e.g. feline panleukopenia, canine parvoviral enteritis, CD, BVD, RP virus,

Epulis is a generic clinical term for tumor-like masses on the gingiva

Pyogenic granuloma: Bright red or blue mass on the gums of dogs

Extremely vascular granulation tissue covered by gingival epithelium

Exaggerated response to local irritation and infection

Reactive and hyperplastic lesions

Peripheral giant cell granuloma; Gingival masses

dogs and cats

Red, smooth, sessile,or pedunculated

Gingival epithelium is hyperplastic or ulcerated, extends deeply into the underlying mass

Fibrous hyperplasia: Generalized and diffuse, or focal, localized to one or more teeth

Mature fibrous tissue with low cellular density, foci of hard

tissue and epithelial nests may be present

Plasma cells band in the gingival stroma adjacent to epithelium

Benign epithelial tumors ("warts") in dogs, cats, and cattle

Papillomaviruses

The virus is host- and fairly site-specific

Infection of basal epithelium of the squamous mucosa, mitosis

viral genome replicates in the differentiating keratinocytes of the stratum spinosum and granulosum, viral assembly and expression in superficial squamous layers

Oral papillomatosis

Incubation period 2 months

Multiple, proliferative cauliflower like,firm, white to gray growths

Microscopically: Lesions is typically verrucous,

Thick keratinizing squamous epithelium covering

thin, branching, often pedunculated cores of vascularized proprial papillae.

Basophilic intranuclear viral inclusions may be found in cells in the outer spinose layers

Ameloblastoma is a slowly progressive invasive but nonmetastatic tumor, consisting of proliferating odontogenic epithelium in a fibrous stroma

Amyloid-producing odontogenic tumors: characterized by dental epithelium, with deposits of amyloid

Acanthomatous ameloblastoma:Tumor arising from the mucosal epithelium or epithelial rests of the

gingiva of dogs

gray-pink papillary to sessile gingival masses,

Tumors of dental tissue

Histologically: Sheets, nodules, and anastomosing cords of polyhedral epithelium bordered by a row of cuboidal to columnar cells with round to oval nuclei

and moderate amounts of cytoplasm

Feline inductive odontogenic tumor: Osteolyticmasses in the rostral maxilla, causing tooth loss or

facial distortion

Complex and compound odontomas

Fibromatous epulis of periodontal ligament origin;Peripheral odontogenic neoplasm

Indistinguishable clinically from fibrous hyperplasia,

Most common in dogs, stromal tumor with interwoven bundles of cellular fibroblastic tissue.

Most common oral malignancy in cats

Occur on the ventral surface of the tongue and gingiva

Locally invasive, especially into bone and local soft tissues

Grossly: Irregular, slightly nodular, red-gray, friable masses, often with an ulcerated surface that bleeds easily

In dog, occur in tonsils

Squamous cell carcinomas

Most common oral tumors in dogs

Malignant, spread to regional lymph nodes

Arise from melanocytes in the mucosa or superficial stroma, mainly on the gingiva and labia

Histologically: Melanomas varies greatly, from a fairly well differentiated heavily pigmented type, to a highly anaplastic amelanotic type

Anaplastic cells show junctional activity

Melanomas

Round or polyhedral cells with a large nucleus and extensive cytoplasm with well-demarcated borders

Some have spindle shaped cells with oval nuclei containing small nucleoli

Most frequently there is a characteristic mixture of epithelial-like and spindle-shaped cells, which have a marked tendency to form nests

DOPA-positive, vimentin 100%, melan A >90%