Skin 4 and Practical Flashcards
What are the different tumours derived from the mesenchymal connective tissue?
Fibrous tissue-
fibroma/fibrosarcoma
equine sarcoid
bovine fibropapilloma
Vascular tumours-
haemangioma/haemangiosarcoma
lymphangioma/lymphangiosarcoma
Lipoma/liposarcoma
Myxoma/myxosarcoma
What is a sarcoid?
What is the triad of predisposing factors?
Do they metastasise or reoccur?
What is a biphasic sarcoid tumour?
How do they grossly and histologically appear?
Unique, locally aggressive fibroblastic skin tumour occurring only in horses
Factors-
bovine papillomavirus 1 and 2, trauma and genetic predisposition
Do not metastasise, characteristically recur following surgery, some regress in one year
Biphasic- both an epidermal and dermal component, although the connective tissue is the predominant proliferating tissue
Gross- highly variable from wart-like (verrucous) to alopecic plaque (occult) to nodular
Histo- resemble fibroma/low grade fibrosarcomas
Where do fibrosarcomas occur?
Are they likely to metastasise?
How do they appear and distribute?
What different presentation can happen in cats after a procedure?
Tumours that occur anywhere in the skin and subcutis of dogs and cats- generally older animals
Metastasis in over 25% of the bloodstream- rapid infiltration
Gross appearance and distribution-
solitary palpable masses from soft to firm, grey to white on the cut surface, frequently poorly demarcated with central necrosis when rapidly growing
Post vaccinal fibrosarcoma- locally invasive spindle cell sarcoma at previous vaccination sites, the disease only occurs in cats, can take 6 weeks to 13 years
lymphocytic infiltration and remnants of vaccine-induced panniculitis with multinucleated giant cells scattered at the periphery of the neoplasia
What age is canine haemangiopericytoma common in and what breeds have higher prevalence?
How do they grossly appear and act?
Where are they usually localised?
How do they appear histologically?
Common in 8-14 yo, boxer, GSH, springer spaniel
Firm to soft, nodular growth, slow-growing, from pericytes around capillaries presents as whirling
Preferentially localised on the forelimb and hindlimb
Histo- tich interlacing bundles and fingerprint whorls of plump spindle cells around vascular lumens
How do haemangiomas appear?
Dome-shaped single or multiple dermal nodules that appear dark red, well-demarcated but not encapsulated
Benign proliferation that closely resembles blood vessels with flattened endothelium and minimal atypia
What kind of tumours are lipomas
How do they appear?
What are they common in and how are they treated?
Lipoma- benign tumours of adipose tissue
resemble normal fatty tissues which are encapsulated by a thin fibrous capsule
they are common in dogs and occasional in cats
Occur in older obese females
Excision is curative
What are the different types of round cell tumours of the skin?
How do they appear?
Histiocytic tumour- canine cutaneous, reactive histiocytosis, histiocytic sarcoma
Mastocytoma/mast cell tumour
Canine extramedullary plasma cell tumour
Cutaneous malignant lymphoma- epitheliotropic cutaneous/ non-epitheliotropic
Round cell tumours appear as a lump formed by spherical cells
What age of a dog is more commonly affected by canine cutaneous histiocytoma?
How do they grossly appear?
How do they appear microscopically?
Common tumours in young dogs <4 years
Solitary small, domed, ulcerated growths, well defined but not encapsulated- benign
Microscopically composed of large pale-staining histiocytes with large vesicular or indented nuclei
They exhibit rapid growth and many mitoses but despite this spontaneously regress within a few months
What dogs are more commonly affected by mastocytomas?
How do they grossly appear?
How do they histologically appear?
How do these tumours behave?
Older dogs- boxer, Boston terrier and labrador
They vary in size up to several centimetres and present at subcutaneous nodules but occasionally swellings, usually localised to the dermis but may extend to the subcutis and musculature
They consist of more or less differentiated mast cells identified by characteristic metachromatic granules
All these tumours must be regarded as potentially malignant, they tend to recur and may metastasise to the local lymph nodes or more generally
Mastocytomas are now designated as low grade or a high grade in correlation with the growing metastatic potential reduction in survival time
What are the two types of cutaneous lymphoma?
Epitheliotropic cutaneous lymphoma-
most frequently recognised form of cutaneous lymphoma, older animals, reported in horses, cats, rabbits and cattle
Gross presentation- erythema, alopecia, ulcerated plaques and nodules on depigmented mucocutaneous junctions
Diagnosis- based on clinical features can be very difficult
Non-epitheliotropic cutaneous lymphoma-
NECL- this is the most recognised form of cutaneous lymphoma in all domestic animals but dogs and cats
More aggressive than ECL and systemic involvement occurs commonly
What species and breed is melancyto$ma common in?
Where do they commonly arise?
When are they more likely to be benign and metastatic?
How does it appear grossly and histological?
Common in dogs and older horses-
dark pigmented dog breeds- Scotties, poodles, Boston terriers
grey horses- Arabs
It May occur anywhere- usually on the face, trunk or extremities- gums, mucosa, palate and lips
Cutaneous melanotic tumours in dogs are most commonly benign- with the exception of digits, scrotum and oral cavity
Grossly- considerable variation, ranging from small dark nodules to large, rapidly growing, light brown/grey masses, ulceration
Microscopic-
non-encapsulated, moderately infiltrative dermal nodules formed by pigmented cells
cells range from polyhedral to pleomorphic, spindle-shaped and fusiform, arranged in sheets or nests, melanin pigments can be bleached out of histology
What malignant neoplasms have the greatest metastatic potential for secondary cutaneous involvement?
Mammary gland adenocarcinomas
Squamous cell carcinomas
Transitional cell carcinomas
Pulmonary adenocarcinomas
Angiosarcomas
What is calcinosis cutis?
What is calcinosis circumscripta or tumoral calcinosis?
Calcinosis cutis-
characteristic of hyperadrenocorticism, almost always in iatrogenic
widespread mineralisation of dermal collagen and basement membrane of adnex
Calcinosis circumscripta or tumoral calcinosis
solitary, dermal lesion of young large breed dogs and horse
localise on bony prominence and repeated trauma is a likely cause, early lesions are fluctuate and chalky white, chronic lesions are firmer
What organ dysfunction is superficial necrolytic dermatitis associated with?
Liver
Which of the following is the most characteristic feature of equine sarcoid?:
Whorling around capillaries
Contact between mesenchymal cells and epidermis
Severe atypia of mesenchymal cells
Intense inflammation
Contact between mesenchymal cells and epidermis
What tumour is this most indicative of in a dog?
Haemangiopericytoma
What is the following lesions most consistent with?
Furunculosis
