Fig. 2.

Clinical and histological findings. (a) Five-millimetre punch biopsy of a skin-coloured papule and hyperpigmented papule from the right lower jaw: yellow circle. (b, c) A haematoxylin-eosin-stained slide of the skin-coloured papule revealed central areas of necrosis surrounded by epithelioid cell granuloma, histiocytes and lymphocytes with a multinucleated giant cell in the dermis, (b) and the hyperpigmented papule showed pigment granules in the dermis (bar=500 and 100 μm, respectively). (d–f) Histochemical staining with: (d) Masson-Fontana for melanin; (e) Prussian blue for iron; and (f) von Kossa for calcium was positive in extra- and intra-cellular macrophages in the upper dermis. (Bars in large images=100 μm; inset, bars=25 μm).