Cutaneous masses Flashcards
Approach to cutaneous masses, cytology of cutaneous masses
What are the groups that cutaneous masses can fall into?
- Inflammatory (infectious, non-infectious)
- Neoplastic
- Non-neoplastic, non–inflammatory i.e. cysts
Describe what is meant by a nodule
- A solid swelling of tissue >1cm
- Circumscribed, solid elevation
- Usually extends into deeper skin layers
Describe what is meant by a cyst
- An epithelium lined cavity containing fluid or solid material
- Smooth, well-circumscribed, fluctuant/solid
- If emptied, will fill up again
Give examples of swellings of non-dermatological origins
- Hernias
- Oedema
- Emphysema
- ## Mammary tumours
Describe emphysema
- Gas in subcutaneous tissue
- Crepitant without pain or swelling, feels like bubble wrap
What are the potential causes of emphysema?
- Severe respiratory disease or lung puncture
- Introduction or air through cutaneous wound
- Rumenotomy or rumen cannulisation
- Clostridial infections (gas produced by clostridial organism)
Explain the role of FNAs in the diagnosis of cutaneous mass lesions
- Gives an idea of the cellular processes taking place in a lump
- Degree of exfoliation can give indication of what cell types are present
- Can identify if there are microbes present, normal cells, inflammatory cells, neoplastic cells
What is required in order to be able to diagnose a cutaneous mass lesion?
- History
- General clinical examination
- Dermatological examination
- Cytology
- Tissue biopsy
- +/- immunohistochemistry
- ## +/- tissue culture
Why is age important in the history for the diagnosis of a cutaneous mass lesion?
- Certain lesions are more likely at certain ages
- E.g. <4mo: juvenile cellulitis, >2yo: histiocytoma (dog), >6yr: neoplasia
What should be included in the history for a cutaneous mass lesion?
- Age
- Travel
- Breed
- History of trauma/fight
- Systemic signs
- Speed of onset of tumour
- Prior history of neoplasia
- Recent injections
Why is travel an important part of the history for cutaneous mass lesions?
- Leishmaniasis
- Systemic fungal disease
- Exotic diseases such as the above can cause cutaneous masses
What could paraneoplastic signs be suggestive of with a cutaneous mass lesion?
e.g. haematemesis with mast cell tumour
What may respiratory signs, weight loss and lethargy be suggestive of with a cutaneous mass lesion?
- Systemic/metastatic neoplasia
- Systemic function infections
What may depression or inappetance be suggestive of with cutaneous mass lesions?
Some microbial infections, abscesses
With what types of cutaneous masses may pyrexia occur?
With systemic/severe cutaneous microbial infections, abscesses
What types of cutaneous masses might cause peripheral lymphadenopathy?
- Neoplastic (metastatic spread to lymph nodes)
- Infectious/inflammatory causing reactive hyperplasia/lymphadenitis if spread
List the features that should be identified and characterised by the dermatological examination of a cutaneous mass
- Solitary or multiple lesions?
- Area of body and size
- Well vs ill defined
- Freely moveable or attached
- Draining tracts/sinuses?
- Pitting on pressure
- Presence or absence of pain
- Inflammatory (can indicate neoplastic or inflammatory lesion)
What is the advantage of no-suction FNAs?
Less likely to damage cells
What cytology techniques can be used in the investigation of cutaneous masses?
- FNA
- Impression smears
What would you expect to see on cytology of an inflammatory mass lesion?
- May be sterile or infectious, acute or chronic
- May see microbes
- Neutrophils (acute), macrophages (chronic)
- +/- eosinophils
What would you expect to see on cytology of a neoplastic mass lesion?
Round, epithelial or spindle cells in neoplastic arrangement i.e. conal population, pleomrphism etc.
Describe the cytological appearance of a cystic mass lesion
- Depends on what is lining the epithelium
- Amorphous collection of cells
What are the key limitations of cytology in the investigation of cutaneous mass lesions?
- Not all cell-types are shed easily, may not always be representative/diagnostic
- May take an unrepresentative sample
- Gives no information re. the tissue architecture, therefore cannot grade neoplasm if present
What are tissue biopsies used for with cutaneous mass lesions?
To confirm putative diagnosis from FNA or where FNA is inconclusive, or for tissue culture where needed