Dermopathology

Question 1

What is the definition of a basal cell carcinoma

Answer 1

Group of malignant cutaneous tumours characterised by the presence of lobules, columns, bands or cords of basaloid cells.

Question 2

What is the histopathology of basal cell carcinomas?

Answer 2

There are islands of basaloid cells with peripheral palisading (cells lined up like a fence) and a haphazard arrangement of cells in the centre. There are numerous mitoses and apoptotic bodies

Question 3

What is some of the information which can be found on a pathological report for different skin cancers?

Answer 3

• The diagnosis of the type of skin cancer,
• The subtype of the cancer,
• Whether there is lymphovascular involvement or perineural involvement,
• High risk histological features (if high risk then needs MDT)
• Depth/level of invasion
• Distance to margins
• pT staging
• For melanoma you need Breslow thickness, ulceration, mitotic index

Question 4

What is the definition of squamous cell carcinoma?

Answer 4

Malignant neoplasm of epidermal and mucous membrane keratinocytes.

Question 5

What are the histological features of squamous cell carcinomas?

Answer 5

• Nests/islands of squamous cells arising from epidermis and extending into the dermis/beyond.
• Variable keratinisation depending upon the differentiation of tumour (well differentiated will produce lots of keratin which will be pink on histology slides)

Question 6

What are prognostic factors for malignant melanoma?

Answer 6

• Tumour thickness,
• Mitotic rate,
• Ulceration,
• Extend of metastatic disease,
• Gene mutations, eg BRAF

Question 7

What are some different stains for melanomas?

Answer 7

• Melan A immunohistochemistry
• Melan A red immunohistochemistry

Question 8

What is the histological appearence of psoriasis?

Answer 8

• Hyperkeratosis (thickened keratin layer),
• Parakeratosis (nuclei within keratin layer),
• Acanthosis (thickened epidermis)

Question 9

What is the histological appearence of eczema?

Answer 9

Spongiotic reaction where there is lots of space between keratinocytes and eosinophil infiltrates

Question 10

What is the histological appearence of granulomatous disease?

Answer 10

• Langhans giant cell (large multinucleated cell)
• Caseous necrosis
• Epithelioid cells
• If TB positive then acid fast bacillus with Ziehl Neelsen stain
• Can also appear in sarcoidosis, leprosy or foregin body reactions

Question 11

When should you do a sentinel lymph node biopsy in a patient with melanoma?

Answer 11

It the melanoma is greater than 1mm thick