Skin

Question 1

Most likely cancer associated with ultraviolet light (March 2015)

a. Merkel cell
b. Dermatofibrosarcoma Protuberans
c. Mycosis fungoides
d. Sebaceous carcinoma

Answer 1

Merkel cell:
o Rare neuroendocrine tumour of the dermis
o Very aggressive (nodes & distant metastases), high rate of local recurrence

Epidemiology

- Elderly (7th and 8th decades)
- Fair skin
- Males > females

Risk factors:

- Sunlight – especially UV light
- Immunosuppression

Dermatofibrosarcoma protruberans:
o Rare, slow growing, exophytic lesion of the dermis & subcutaneous tissues
o Most common in the trunk
o Excellent outcome following complete surgical excision

Epidemiology:

- Slight male predilection
- Can occur at all ages, most common 2nd – 5th decades

Mycosis fungoides:
o Cutaneous T cell lymphoma

Epidemiology: more common in males and African Americans

Disease course:

- Indolent (may be for many years) with a rash which mimics dermatitis and eczema
- Patch, plaque, cutaneous tumour
- Becomes more invasive: local lymphadenopathy then spreads to solid organs such as the lung & brain

o Treatment is with palliative intent

Sebaceous carcinoma:
o Rare tumour of the sebaceous glands
o Most commonly arises in the periocular area (eyelid)
- More common on the upper eyelid

Epidemiology:

- More common in women
- Peak in the 7th decade
- May be seen in younger patients w a history of radiation to the face

ANSWER: Merkel cell cancer is most assoc w UV light

Question 2

Which is not associated with squamous cell skin cancer? (March 2014)

a. SLE
b. CLL
c. Post renal transplant
d. HPV
e. Sun rays

Answer 2

Risk factors for SCC:
o	Exposure to UV radiation from the sun
o	Fair skin
o	Sun damaged skin & actinic keratosis (solar keratosis)
o	Previous Dx of skin cancer
o	FHx
o	Increasing age
o	Repeated exposure to radiation
o	Immunosuppression
o	HPV infection
o	Tobacco use
o	Leukoplakia or Bowen’s disease

• Patients w CLL are 9x more likely to develop SCC

ANSWER: SLE is not established as a risk factor for skin SCC

Question 3

What disease affects the skin and liver? (March 2015)

a. Wilson disease
b. Dermatitis herpetiformis

Answer 3

Dermatitis herpetiformis
o Characterised by intensely pruritic urticaria & grouped vesicles

Associations:

- Coeliac disease – responds to a GF diet
- More common in young men

Pathology:

- Immune complex deposition in the skin
- Cross reactivity of anti-gliadin antibodies w junction anchoring components
- Accumulation of neutrophils & fibrin giving large subdermal blisters

ANSWER: Wilson disease does not affect the skin and dermatitis herpetiformis does not affect the liver