Skin Flashcards
What are the 4 steps to the diagnostic approach for a skin mass?
- History
- Physical parameters
- Aspiration and cytology
- Biopsy
What should you ask regarding the history of a skin mass?
Duration, previous masses, concurrent problems
What should you ask/note about the physical parameters of a skin mass?
Size, location/distribution, color, palpation (fluid, firm, soft), gross changes (cystic, solid, dermis/SQ)
What is further testing that can be done for a skin mass?
- Bacterial culture
- Immunohistochemistry
- Radiography
- Eval other tissues (i.e. lymph nodes)
- +/- CBC, Chem
What are 3 differentials to consider for a skin mass?
- Neoplasms
- Inflammatory
- Non-neoplastic/non-inflammatory
What neoplasms should be considered as a skin mass differential?
Round cell, mesenchymal, epithelial, benign, malignant
What inflammatory lesions should be considered for a skin mass?
Dermal, follicular, epithelial, SQ
What non-neoplastic/non-inflammatory lesions should be considered for a skin mass?
Cysts, hamartomas, scarring
What infectious causes can be considered for a skin mass?
Bacteria, fungal, protozoal
What are the 4 types of biopsies that we can take from the skin?
Punch, excisional, incisional, shave
When would we take a punch biopsy?
What does it look like?
For sampling possible cancers, tumors, and inflammatory skin conditions.
What is an excisional biopsy?
What does it look like?
Complete lesion removed with margin of normal skin down to adipose tissue. Useful if suspect melanoma, skin cancer, small bulla.
What is an incisional biopsy?
What does it look like?
Cross-section wedge of tissue thru center of lesion. Useful when lesion is too big to excise and diagnosis is unsure (e.g. keratoacanthoma vs. squamous cell carcinoma).
What is a shave biopsy?
What does it look like?
Horizontal shave of the skin lesion with only superficial portion of the dermis. Use only to remove benign lesions, as may not get entire depth of lesion.
What biopsy type leaves the largest scar?
Shave biopsy
What biopsy type should you never use if you suspect melanoma?
Shave biopsy
What 4 things can you put a biopsy in?
Water, 10% formalin, ethanol, pack on ice
What is the appropriate ratio of formalin to sample?
Formalin : Biopsy = 10-20 : 1
What two differentials would be appropriate when there is a skin mass with a draining tract?
Foreign body, trauma
What bacteria forms sulfur granules (tiny yellow clumps)?
Actinomyces spp
Where does Actinomyces live and what type of organism is it?
Lives in the soil and is saprophytic
What 8 specific questions would you ask an owner about a skin mass?
- Has he injured the site?
- Are there other masses?
- Duration of this lesion?
- Does it get bigger/smaller?
- Does it bother dog’s movement?
- Food/water intake?
- Recent treatments?
- Anything else you noticed?
What does this cytology slide show?
Mast cell tumor
What would mast cell tumors look like on histo?
Sheets of differentiated mast cells intermixed with a moderate number of eosinophils. The mitotic rate is low. The neoplastic mass cells extend into the deep surgical margin.
A _____ grade mast cell tumor has a lower risk of metastasis and new _____ development compared to _____ grade mast cell tumors. Prognosis for this tumor is _____ to _____.
low, tumor development, high, fair, good
If surgical clearance is _____ and _____ is a concern, you may want to take wider margins.
not complete, reoccurence
What would be good differentials for:
- Alopecic mass
- 2x1cm, firm
- In skin above eye
- Only mass identified
- Has been there about a week and is growing rapidly
- Mast cell tumor
- Fibrosarcoma
- Foreign body granuloma
- Nodular sebaceous hyperplasia
What would be next steps to take if a fine needle aspirate and cytology were non-diagnostic?
Biopsy, histopath
What is this?
Ruptured hair follicle with macrophages and neutrophils
What is this?
Hair follicle with fungal hyphae
What are the top 3 causes of ringworm in dogs?
- Microsporum canis* (70%)
- Microsporum gypseum* (20%)
- Trichophyton mentagrophytes* (10%)
What is the top cause of ringworm in cats?
Microsporum canis (90%)
Ringworm is _____ and _____ in immunocompetent animals.
Self limiting, self resolving
What are types of whole body therapy that can be done for ringworm?
Whole body lime sulfur dips, miconazole, miconazole/chlorhexidine shampoo
What are types of systemic therapy we can do for ringworm? What is a possible side effect?
Itriconazole, Fluconazole, Terbinafine;
Some animals may develop neutropenia (idiosyncratic reactions)
