Organs of Special Sense Pathology Image-Based Learning

Investigating deathness - BAER test

Brainstem Auditory Evoked Response Results

I – cochlear nerve of the inner ear

II – intracranial cochlear nerve/ nucleus

III – dorsal nucleus of trapezoid body

IV – lateral lemniscus pons

V – caudal colliculus

VI – medial geniculate nucleus

BAER slope shifted to the right with conductive hearing loss

Otitis media/interna

Red - fluid filled bullae

Blue - air filled bullae

Yellow - gadolinium enhancement (increased blood supply with inflammation)

Bulla radiographs - Loss of air filled bullae

Myringotomy

Feline nasopharyngeal polyp

Sensory hair cells of crista ampulla (semicircular canal)

Movement: endolymph bends hair cells

Different orientations mean directionally sensitive

Peripheral vestibular disease

Peripheral vestibular disease - hypothyroidism

Vestibular disease and bilateral facial palsy

Second image: after 2 weeks of Levothyroxine therapy

Central vestibular disease

Paradoxic vestibular syndrome

Carcinoma in 4th ventricle

Otitis media-interna – secondary meningoencephalitis

Infection of middle ear cavity where peripheral disease has progressed to central disease

Paradoxical vestibular disease

Lesions resulting in loss of inhibitory influence of cerebellum

Paradoxical vestibular disease

Cystic tumour between the feedback from the cerebellum and brainstem

Tilting of the head due to nerve impulses firing only on one side resulting in contraction of extensor muscles on the other side

Thiamine deficiency - Bilateral vestibular disease

Malassezia infection

Sebaceous gland hyperplasia, hyperkeratosis, ceruminous debris

Otitis externa - chronic

Thickened, leathery, narrowing of the external acoustic meatus (stenosis), hyperplasia, dermal changes, osseous metaplasia of soft tissues

Otitis externa

Narrowing of the external acoustic meatus (stenosis), hyperplasia, dermal changes, oedema (acute), fibrosis (chronic), mixed inflammation (plasma cells, lymphocytes, mast cells, neutrophils), osseous metaplasia of soft tissues

Otitis externa

Cartilage splitting (fracture), fibrosis, healed haematoma

Aural haematoma

Notoedres cati

Otodectes cyanotis

Psoroptes cuniculi

Neotrombicula autumnalis (Harvest mite)

Atopic dermatitis - Primary cause of otitis externa (OE)

Hyperpigmentation, lichenification, pyoderma secondary to pruritus

Allergic skin disease - Primary cause of otitis externa (OE)

Hyperpigmentation, lichenification, pyoderma secondary to pruritus

Ear margin seborrhea

Waxy crusts, small fissures

Dog, ears. Normal ceruminous glands in clinically healthy dog

Increased keratin thickness layers, increased size and numbers of glands

Mild epidermal hyperplasia and compact orthokeratotic hyperkeratosis, mild infundibular hyperkeratosis, numerous sebaceous glands and multifocal ceruminous gland ectasia (L)

Otitis externa, dog pinna

Marked multifocal ceruminous gland hyperplasia and ectasia, and periadnexal pigment-laden macrophages

Lupus erythematosus

Scaling, crusting (multifocal to coalescing)

Pemphigus foliaceus

Scaling, crusting (multifocal to coalescing)

Vascular disease leading to primary otitis externa

Auricular infarction, frost bite, Goat. Dry gangrene. Note the clear line of demarcation between dead and living tissue

Cat ear canal, Malassezia chronic infection

Otitis media

Ferret, ciliated epithelium (lung) with mycoplasmosis

Multifocal loss of cilia with mycoplasma-like organisms (arrows)

Mycoplasm trying to blend in with the cilia, but ultimately causing cilia death (c)

Otitis media gross pathology (Mycoplasma bovis)

Caseous, necrotic exudate, suppurative inflammation

Bilateral suppurative otitis media

Tympanic cavities bilaterally filled with soft, yellow-tan exudate (pus; otitis media).

Arrow; eustachitis

Otitis media

Microtia

Small pinna - La Mancha goat

Nasopharyngeal polyps

Gross pathology: pedunculated to polypoid mass with smooth surface, variably ulcerated mucosal surface

Histopathology: fibrovascular core, lymphocytes, plasma cells, histiocytes

Nasopharyngeal polyps

Hyperplasia

Tympanokeratoma

Gross pathology: tympanic cavity filled and expanded with pasty, yellow to pale-tan material, loss of normal structures (ossicles)

Histopathology: keratin surrounded by squamous epithelium, granulation tissue +/- otitis media (+/-) cholesterol clefts and granulomatous inflammation (cholesterol granulomas)

Ceruminous gland adenocarcinoma

Multifocal to coalescing nodules; firm, pale tan; EAM obstruction (perpetuates otitis externa!)

Equine aural plaques (papillomatosis)

Transition of viral plaque (black arrow) into SCC. Note the proliferative mass with disorganization of the keratinocyte layers and the invasive islands of neoplastic epithelium (*)

Demodex

Sarcoptes scabiei

Otodectes

Dermatophytosis

Tympanic membrane (normal)

1. Pars tensa

2. Edge of the pars flaccida

3. Blood vessel

4. Head of Malleus

5. Promontory

6. Cerumen and hair

Tympanic membrane

Small amount of cerumen and hair adjacent

Ear canal

Epithelial fold formation, stenosis, ceruminous gland hyperplasia causing polypoid appearance, ulceration (bleeding)

Ear canal

Erythema and mild ulceration of horizontal canal, abnormal opaque tympanic membrane

Ear canal

Opaque tympanic membrane, erythema and ulceration, purulent discharge

Ear canal

Erythema, ulceration, macerated epithelium (white areas), brown mucopurulent discharge

Ear canal

Erythema, stenosis, ulceration, sebaceous gland hyperplasia (small white spots)

Severe stenosis of the ear canal

Ear canal

Brown ceruminous discharge caused by Malassezia pachydermatis

Ear canal

Purulent discharge due to bacterial infection

Ear canal macerated epithelium

Ear canal - hirsuitism (excess hair)

Mucopurulent discharge from the middle ear

Ear canal - profuse slimy purulent discharge due to biofilm production

Grass seed adjacent to the tympanic membrane

Tan colour otic discharge and otitis
Many neutrophils (hypersegmented nuclei)
Phagocytosed bacteria (cocci) --> Staphylococcus or Streptococcus

Ceruminous otitis

Unipolar budding yeat --> Malassezia pachydermatis

Purulent, painful and ulcerated malodourous otitis
Small numbers of neutrophuls (hypersegmented nuclei)
Rod shaped bacteria --> Pseudomonas, Proteus, E.coli, Klebsiella
Small number of cocci also present

6 month old F cat with pruritic waxy ears - ear mites (otodectes cynotis)

Mild erthema of the pinna and ear canal entrance, dark brown coffee grounds like ceruminous discharge, white specks within cerumen

6 year old dog with severely painful and smelly unilateral otitis of 5 months duration

Purulent discharge, small ulcerations on the concave pinna and horizontal canal, tumour on the cranial lateral pinna - covered in crust, cobblestone appearance to the ear canal suggestive of ceruminous gland hyperplasia , inflammed and opaque tympanic membrane

6 year old dog with severely painful and smelly unilateral otitis of 5 months duration - cytology - bacterial infection

Numerous rod bacteria and squames - gram negative --> e Pseudomonas, Klebsiella, Proteus, E.coli

Ceruminous otitis

Head shaking, malodour, ceruminous discharge, erythema and oedema of the ear canal, ceruminous gland hyperplasia (cobblestone appearance), stenosis of the distal horizontal ear canal, numerous yeasts --> Malassezia pachydermatis and squame

Pemphigus foliaceus

Scaling and crusting along the ear pinnal margins that is matting the coat, large pustules in the groin with erythematous margina, axilla is alopecic with a large peripheral epidermal collarette and erosions, hyperpigmented macules, squames on cytology, acanthocytes

Vasculitis/ vasculopathy

Left pinna - alopecia, hyperpigmentation, linear ulceration covered with crust and eroded pinnal edge

Right pinna - extensive erosion, alopecia, crusting

Macropalpebral fissure syndrome

Dogs with a prominent fold of skin over the nose

Corneal ulcer and entropion

Entropion - Shar Pei

Nasal fold trichiasis (rubbing on the cornea)

Bulbar conjunctiva of labrador - ectopic cilia

Blepharitis with thickened and calcified Meibomian glands

Puppy strangles - Blepharitis

Local blepharitis (inflammation of the meibomian gland)

A - chalazion or meibomianitis

B - Chalazion on the left lower eyelid of a 9-year-old male dog. This consists in an inflammatory lesion of the meibomian gland, associated with secretion accumulation

C - Adenoma

Parasitic blepharitis (Demodex species)

Circumferential alopecia, crusting, discharge and erythema

Protrusion of the nictitans gland (cherry eye)

Common in Bulldogs

Conjunctivitis

Hyperaemic and oedematous conjunctiva, vasodilation, increased blood flow, lymphoid follicles, ulceration, fibrosis

Habronemia conjunctivitis

Conjunctival hyperemia and thick mucopurulent ocular discharge

Chlamydophila felis - unilateral conjunctivitis (infection)

Conjunctivitis in cats associated with feline herpesvirus 1

Infectious Bovine Keratoconjunctivitis (Pink eye) - Moraxella bovis

Immune-Mediated Keratoconjunctivitis Sicca (KCS)

Decreased tear film quantity and quality > dry eye

Keratoconjunctivitis

Corneal fibrosis, pigmentation and neovascularisation

Schirmer Tear Test (STT)

Retained spectacles > leads to abscess formation

Meibomian adenoma (neoplasm of the eyelid)

Limbal melanocytoma (neoplasm of the eyelid)

Squamous cell carcinoma of the eyelid

Mastocytoma of the eyelid

Squamous cell carcinoma, bovine

Polygonal neoplastic cells with scant to moderate amounts of eosinophilic cytoplasm, whorls of lamellar keratin (keratin pearls) within the centers of trabeculae and islands.

Ocular dermoid congenital condition