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Winter 2017, Vol. 25 No. 4

Hong Kong J. Dermatol. Venereol. (2017) 25, 214


Answers to Dermato-venereological Quiz

Answers to Dermato-venereological Quiz

ECY Chu 朱灼欣 and MT Ng 吳孟婷

  1. The differential diagnosis include: immunobullous disease, vasculitis, bullous lupus erythematosus and skin malignancy.
  2. The skin biopsy shows a piece of skin bearing wedge-shaped dermal lesion with infiltrative borders and extending down to the deep dermis. It is composed of solid sheets of plump epithelioid cells with large oval nuclei, conspicuous nucleoli and a small amount of pink cytoplasm. There is no maturation and mitotic figures are seen in the deep part of the lesion. Immunostaining shows positivity of the lesional cell for S100 and Melan-A, while Ki-67 positivity is noted in the deep part of the lesion.
  3. The diagnosis is malignant melanoma. Melanoma is a form of skin cancer that arises from melanocytes. Melanomas mostly affect the skin, although melanoma can also occur in the eyes and other parts of the body, such as the intestine. Melanoma is much less common than basal cell carcinoma and squamous cell carcinoma, but melanoma is more dangerous as it is more likely to metastasise. Melanomas can develop on any part of the skin: in men, the chest and back are most likely to be affected while in women, the legs are the most common site for melanoma. Frequent sun-exposure, a large number of naevi, presence of five or more atypical naevi, giant congenital melanocytic naevus, pale skin, family or personal history of melanoma are regarded as risk factors for melanoma. Changes in the appearance of the lesion are key indicators of melanoma. The ABCDE examination (A: asymmetric, B: border, C: color, D: diameter, E: evolving) of the pigmented lesion are key to detecting these lesions. Some melanoma specific structures can be visualised on dermoscopy. However, if melanoma is suspected, urgent skin biopsy should be arranged.
  4. Wide local excision with complete regional lymph node dissection in patients with positive sentinel lymph node is the mainstay of treatment for early melanoma. Interferon alfa-2b and ipilumimab can be used as adjuvant treatment after excision in patients who are free of disease but are at high risk for recurrence. For the treatment of advanced ?stage melanoma, chemotherapy is used less frequently nowadays due to the development of the more efficacious agents including checkpoint inhibitors like ipilimumab and targeted therapies like vemurafenib or imatinib.