L5-Neoplasia and miscellaneous diseases Flashcards
Paraneoplastic skin diseases
Superficial necrolytic dermatitis
Paraneoplastic syndrome
Hepatocutaneous syndrome
• Dog, rarely cat
• Associated with glucagon-secreting tumors
of pancreas, diabetes, liver disease
• Liver disease à nodular liver with areas of
fibrosis
• Bilaterally symmetrical, muzzle, lips,
periocular skin, distal limbs
• Erythema, erosive to ulcerative, crusting
• Thick footpads
• Diagnostics: biopsy!
• Look for underlying cause
Paraneoplastic skin diseases
Feline paraneoplastic alopecia
Rare dermatoses associated with internal
malignancies
• Dermatosis occurs after the development of a malignant
tumor
• Older cats with pancreatic carcinoma , biliary
carcinoma, and hepatocellular carcinoma
• Skin lesions are potentially reversible if
malignancy is excised prior to metastasis
• Mets to liver or lungs usually already occurred at
diagnosis
• Non-pruritic, rapidly progressive symmetrical
alopecia
• Shiny/glistening appearance to skin; ventral
abdomen
• Systemic signs; lethargy, anorexia, weight loss
Paraneoplastic skin diseases
Nodular dermatofibrosis
Multiple cutaneous collagenous
hamartomas
• Autosomal dominant inheritance
• Germans Shepherd, Golden retriever, boxer,
Belgian shepherd
• Associated with renal
cystadenocarcinomas (often bilateral)
and/or uterine leiomyomas
• Lesion
• Similar to collagen hamartomas -> multifocal
(can be hundreds)
• Overlying skin: normal, thickened,
hyperpigmented, alopecic or ulcerated
Paraneoplastic skin diseases
exfoliative dermatosis
Lots of scaling, crusting, and erythema
• Can be localized or generalized
• Usually associated with another disease
• Thymoma, epitheliotropic lymphoma, drug
reactions, etc.
Eosinophilic granuloma complex
Group of cutaneous lesions
• Skin, mucocutaneous junctions, oral cavity
• CATS, dogs, horses
• Usually has an underlying allergic etiology
• Canine
• Rare, suspect hypersensitivity
• Huskies, males, young predisposed
• Nodules or plaques, in mouth and tongue • Equine
• Nodular lesions on withers, back, neck
• Usually spring and summer
• Suspect allergic/hypersensitivity response
Feline eosinophilic complex
Feline eosinophilic plaque
Felis domesticus allergen I (FELD I)
autoantigen
• Raised, erythematous, ulcerated plaques
• Pruritic – will see self trauma
• Ventral abdomen, medial thigh, perineum
• Feline eosinophilic granuloma
• Linear granuloma, NOT pruritic
• Young cats, can spontaneously regress
• Caudal thigh, face, chin, lips
• Raised nodules, pink to orange, alopecia
• Indolent ulcer
• Ulcerated lesion on upper lip adjacent to philtrum
• Not painful, not pruritic
Sterile cutaneous diseases
Canine juvenile cellulitis
Puppy strangles
• <4 months old
• Idiopathic disease – cause and
pathogenesis unknown
• Suspect immune dysfunction
• Papules, pustules, crusts, alopecia,
EDEMA
• Face, muzzle, ears, feet, vulva, prepuce
• Bilaterally symmetrical, painful, non-pruritic
• Fever, anorexia, arthritis in multiple joints
Sterile cutaneous diseases
Porcine juvenile pustular psoriasiform dermatitis
Disease of weanling pigs
• Unknown cause
• Landrace seem predisposed
• No clinical significance, just aesthetics
• Symmetrical, nonpruritic, scaly erythematous
papules
• Progress to ring-shaped erythematous lesions
• Coalesce to form mosaic pattern
• Abdomen and inner thigh
• Spontaneously resolves in about 4 weeks
Sterile cutaneous diseases
Sterile granuloma
Uncommon in dogs, rare in cats, horses
• Likely immune-mediated, no infectious
cause
• Solitary or multiple erythematous papules,
nodules, plaques
• Dogs and horses
• Usually non-painful, not pruritic
• Likes face and distal extremities
• Cats
• Symmetrical and pruritic
• Pariauricular, pinna, head
Laminitis – equine hoof
Main lesion is dermal-epidermal
separation due to loss of basement
membrane between the two
• Loss of structural integrity of hoof wall to P3
• Secondary dermal laminae collapse à loss of
capillaries à ischemia
• As tendons pull, eventually rotate P3
• 3 pathways to development
• Inflammatory – grain overload, GI disease,
sepsis
• Inflammatory toxins destroy lamellar basement
membrane
• Endocrine – PPID, insulin resistance, obesity
• Stretching of secondary lamellae
• Contralateral limb laminitis
• Poor blood flow and ischemia
Normal hoof wall histology
No rmal Hoof Wall
Neoplasia
Biopsy tips
Incisional (wedge) or excisional (whole thing)
• Mark one side (cranial, caudal, etc.)
• Suture or tissue ink
• Excisional – get wide margins if possible
• MCT requires at least 3 cm on all sides + one fascial plane deep
• Biopsy report – what info do we put there
1. What is it
2. How bad is it – grade, vascular invasion
3. Did you get all of it – margins
4. Do we need additional workup? IHC?
5. Maybe some papers for reference for prognosis
Neoplasia
Papillomas
Often caused by infection with
papillomaviruses
• Tropism for cutaneous and mucosal squamous
epithelium
• Generally host specific
• Exceptions:
• Bovine papillomavirus à equine sarcoids
• Exophytic, hyperkeratotic, hyperplastic
epithelium with stalk
• Fibropapilloma – expansion of dermal tissue
• Nodule or plaque with thickened epidermis
• Dogs – mainly oral cavity
• Also have inverted papilloma (grows inward)
Neoplasia
Squamous cell carcinoma
Most common neoplasm in cats, 2 nd in
dogs
• Increased incidence in short-haired breeds
with light skin
• Most common neoplasm of claw bed in
digit of dogs (large breed, black-coated), cats
• Arise from keratinocytes, common in sun-
damaged skin
• Carcinogens (UVB is most important)
• Usually locally invasive, slow to metastasize (lungs, regional LN)
• Poorly circumscribed, firm, nodular – often
ulcerated
• Ventral trunk, limbs, digits, lips, ears
neoplasia
Hair follicle tumors
Infundibular keratinizing acanthoma,
Trichoepithelioma, Tricholemmoma,
Pilomatricoma, Trichofolliculoma,
Trichoblastoma
• Each tumor attempts to recapitulate specific
segments of the hair follicle
• Most are benign – excision is curative
• Some malignant varieties of trichoepitheliomas and
pilomatricomas (“matrical carcinoma”) exist
• Rare in species other than dogs and cats
• Unknown pathogenesis
neoplasia
Keratoacanthoma (birds)
Benign tumor, mainly in young broilers
• Does not met, can be locally invasive
• Can lead to carcass condemnation
• Seasonal, spontaneous regression related
to molting cycle
• Originates from epithelium at margin of
hyperplastic feather follicles
• Gross:
• Nodular to ulcerated, single to coalescing skin
lesions – crater-shaped with raised margins
• Pectoral, dorsopelvic, femoral feather tracts
• Ulcers can have central core of keratin
Neoplasia
Sebaceous adenoma
Subclassified by appearance: adenoma,
ductal adenoma, epithelioma,
adenocarcinoma
• Sebaceous gland hyperplasia is uncommon,
adenoma and epithelioma are more common
• Sebaceous hyperplasia
• Single or multiple SMALL raised, waxy masses,
usually head, eyelids, limbs, trunks
• Poodles, Cocker Spaniels
• Sebaceous epithelioma or adenoma
• Solitary, firm, nodular mass usually head, neck,
ears and dorsum
Neoplasia
Perianal gland adenoma/carcinoma
Perianal gland (Hepatoid gland, circumanal
gland)
• Modified sebaceous glands in dogs/canids
• Usually in perianal region, can arise in proximal tail
• Adenomas common in aged, INTACT males
• Androgen-dependent, 95% regress after castration • Carcinomas are rare (no response to castration)
• Adenoma: Raised, tan, nodular growth, +/-
ulceration and infection; can arise in proximal tail
• Carcinoma: Similar to adenoma; occur almost
exclusively in perianal region; may extend directly
into the pelvic canal or metastasize to regional
lymph nodes (late event)
Neoplasia
Anal sac adenocarcinoma (AGASACA)
Most common malignant tumor in perineum of
dogs
• Highly invasive, often metastasizes to regional LN
• Elevated parathyroid hormone related protein
(PTHrP) à hypercalcemia (HHM), hypophosphatemia
• 2 nd-most common cause of tumor associated
hypercalcemia (lymphoma is #1)
• Perineal mass, ventrolateral to anus (usually
unilateral)
• Rarely invades rectum, mainly expansile mass (+/-
enlarged sublumbar LN)
• +/- metastatic calcification (Ca x P = >70) in
various organs (kidneys, stomach)
neoplasia
Melanocytoma and melanoma
Melanocytoma – benign version
Tumors of melanocytes
• Common in dogs
• Solitary, well-demarcated, gray to black, smooth
• Horses: common in gray horses.
• Pigs: spontaneously regress
• Mainly in Durocs • Melanoma – malignant version
• Common in dogs
• Head, limbs, digits, nail bed, oral cavity
• Variably demarcated, dome or plaque-like, often ulcerated
• Gray to black on cut section
neoplasia
Fibroma/fibrosarcoma
Tumor of fibroblasts and collagen
• Originate from subcutis
• Most common in dogs and cats
fibroma
• Solitary, soft-to-firm, round, dome shaped mass
• Ulcerated due to self-trauma
• Fibrosarcoma
• Soft-to-firm, poorly circumscribed, infiltrative
mass
• Usually ulcerated
• Trunk or limbs
• Slow to metastasize
Vaccine-associated fibrosarcoma
Seen in cats, especially older ones
• Overactive reparative response at vaccine site à
malignant transformation of mesenchymal cells
• Often rabies vaccine due to adjuvant
• Irregular, firm, multilobular mass in vaccine
site
• Invasive, poorly circumscribed
• Often involves subQ and underlying muscle
• Locally invasive, will recur frequently
• Uncommon for metastasis, but can happ
Equine Sarcoids
Most common equine skin neoplasm – young
adults
• Locally aggressive, nonmetastatic fibroblastic
skin tumor
• Appaloosas, Quarter horses, Arabians,
Thoroughbreds
• Associated with BPV types 1,2, and possibly
3.
• Most common on head, neck, legs, ventral
abdomen
• Many types
• Based on gross appearance
Hemangiosarcoma
Tumor of vascular endothelium
• Can be primary to skin or a site of metastasis
• Tends to occur in lighter to white haired
areas
• Chronic solar irradiation may play a role
• Tends to be less aggressive than visceral
types
• Single, well-defined mass, red/brown to
black
• Exudes blood when excised
• May have alopecia, thickened skin,
hemorrhage, ulceration
Cutaneous histiocytoma
Benign tumor of young dogs
• Proliferation of dermal antigen-presenting
dendritic cells (Langerhans cells)
• Dome or button shaped, pink, hairless
mass
mediated regression
• Usually seen on head and pinna
• Older lesions may be ulcerated
• Often undergoes spontaneous immune-
Cutaneous langerhans histiocytosis
Similar to histiocytoma, more wide-spread
• Langerhans cell origin
• Syndrome in dogs – Shar Pei over-represented
• Multiple skin nodules that resemble
histiocytomas
• Can be markedly widespread
• Skin and other organs affected
• Known to metastasize to lymph nodes, other
organs
• à worse prognosis!
• Can regress, though takes MUCH longer to
occur
Mast cell tumor
Proliferation of mast cells – most common in dogs
• Mutation in c-kit proto-oncogene may be involved
• Solitary to multicentric, dermal to subcutaneous,
nodular to pedunculated masses
• Ulceration, erythema, edema common
• Canine: trunk, limbs, head
• Boxers, Bostons, Labs, predisposed
• May have gastroduodenal ulceration due to excess histamine release
• Equine: head, neck, trunk, and limbs
• Cats: more common in older cats
• Usually benign
• Additional tests usually need to accurately assess
prognosis
• Cytology – careful when you poke!
Cutaneous lymphoma
Can be primary in skin or part of systemic
disease
• Epitheliotropic
• Invades epidermis and adnexal epithelium
• Cutaneous T-cell lymphoma (CTCL)
• “Mycosis fungoides”, described in many species
• Older animals typically
• Erythematous, exfoliative dermatitis, plaques to
nodules
• Depigmentation of mucocutaneous junctions
• Non-epitheliotropic
• Stays in dermis and subQ
• Tends to be B-cell
• Horses: T-cell-rich B-cell lymphoma
• Quarter horses predisposed
• Multiple masses within skin
Plasmacytoma
Tumor of plasma cells
• NOT the same as multiple myeloma!
• Common in middle-aged to older dogs
• Rare in cats
• Usually benign
• Associated with areas of chronic immune
stimulation (gingiva, pinna, chin and paws)
• 1-2 cm, raised, smooth, well-circumscribed, firm-
to-soft, pink-to-red nodules
