December 2, 2015 - Malignant Skin Lesions

Question 1

Risk Factors for Skin Cancer

Answer 1

Skin type

UV light exposure

Genetics

Immunosuppression

HPV

Environmental toxins

Ionizing radiation

Question 2

Clinical Pearls of Skin Malignancies

Answer 2

More common with advancing age

Lesions often single (but not always)

Lesions usually asymmetrical

Inflammation may or may not be present

Premalignant lesions may or may not be present

Growth rate is variable, BUT generally has evolved over months gradually

Any lesion satisfying the above, and for which a non-malignant diagnosis is not immediately evident, YOU MUST BIOPSY

Question 3

Cutaneous Neoplasms and Cell of Origin

Answer 3

Squamous cell carcinoma - keratinocytes of the spinous layer

LC Histiocytosis - Langerhans cells

Bascal cell carcinoma - Basal keratinocytes

Melanoma - Melanocytes

Question 4

Basal Cell Carcinoma (BCC)

Answer 4

Most common malignancy in humans

Related to UV light exposure

Does not metastasize… Direct spread

Central ulcer is often present

Question 5

Basal Cell Carcinoma - Key Features

Answer 5

Rolled edge

Translucent

Central ulcer is common

Telangioectasis

Sun-exposed areas

Question 6

Squamous Cell Carcinoma (SCC)

Answer 6

Come from the precancerous lesion: actinic keratosis

Low risk of metastasis (about 5% over 2 years), except on the lips or ears or in the context of immunosuppression or in areas of scarring.

If they metastasize, the outcome is terrible.

Question 7

Actinic Keratosis

Answer 7

Can develop into SCC

Question 8

Bowen’s Disease: SCC in Situ

Answer 8

Restricted to the epidermis

Question 9

Melanoma

Answer 9

Cancer arising from melanocytes.

Early detection is an important goal in cutaneous melanoma management.

Tumour depth is the most important prognostic factor for cutaneous melanoma.

Melanoma that has spread often has a very poor prognosis.

Question 10

Growth of Melanoma

Answer 10

First starts in a radial growth phase where the lesion gets bigger and grows outwards.

Next comes the vertical growth phase where it expands deep into the tissue. This is BAD. Ideally, you want to catch and excise the menaloma before this point.

If it has less than 1mm depth, there is a 95% chance of survival. If however, it is deepr than 4mm, there is less than a 20% chance of survival.

Question 11

Hutchinson’s Sign

Answer 11

The leeching of pigment onto skin around the nail. This is highly suggestive of melanoma.

Question 12

Melanoma Prognosis

Answer 12

5-year survivals

Stage I is less than 1mm thickness and has >95% chance of survival

Stage II has >2mm thickness and has about a 70% chance of survival

Stage III has nodal involvement, but no metastasis and is about 45% chance of survival

Stage IV has distant metastasis and has less than a 10% chance of survival