Comedonal granuloma annulare
How to cite this article: Kapoor P, Kumar S. Comedonal granuloma annulare. CosmoDerma 2022;2:87.
A 56-year aged female presented to us with erythematous lesions on forearms for 3 years. Physical examination showed erythematous papules and plaques on extensor surface of forearms. The largest plaque had raised borders studded with open comedones [Figure 1]. All routine investigations were normal. Dermoscopy showed blurry vessels over a pinkish-red background, yellowish-orange structureless areas, and open comedones filled with keratotic plugs [Figure 2].
Skin biopsy showed a palisading granuloma in reticular dermis around focus of fibrin and mucin deposition and incomplete collagen degeneration. Dilated follicular infundibulum filled with keratinous material corresponding to a comedo was seen [Figure 3].
Degeneration of collagen and elastin is a hallmark histological feature of granuloma annulare. Loss of dermal support induces distension of infundibular canal of sebaceous follicle resulting in open comedones overlying lesions of granuloma annulare. Comedonal granuloma annulare should be differentiated from perforating granuloma annulare, actinic comedonal plaque, granuloma multiforme, and annular elastolytic giant cell granuloma.
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