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Autumn 2017, Vol. 25 No. 3

Hong Kong J. Dermatol. Venereol. (2017) 25, 144-145

Dermato-venereological Quiz

CMT Cheung 張敏彤, MM Chang 張苗, PCL Choi 蔡祥龍

A middle-aged Chinese woman presented with a one-year history of mildly painful skin rash on shins. She had underlying hypertension, obesity, and Graves' disease, which was treated with radioactive iodine two years previously and was currently euthyroid. The eruption occurred on the shins and was progressive in nature. There was no history of insect bites or trauma. Examination revealed symmetrical skin-coloured to mildly erythematous waxy indurated plaques on bilateral shins (Figure 1). There was associated hypertrichosis. Patient was otherwise afebrile and clinically well. A punch skin biopsy was obtained on left shin for histological evaluation (Figures 2 & 3).

Figure 1

Figure 2 Skin biopsy. Haematoxylin & eosin stain, magnification x 40.

Figure 3 Alcian blue stain, magnification x 200.

Questions

1. What are the differential diagnoses?

2. What does the biopsy show?

3. What is the diagnosis?

4. What is the treatment?