Granuloma annulare histology shows which feature?

• A. Collagen degeneration
• B. Caseating granulomas
• C. Spongiosis
• D. Epidermal atrophy

Answer: (A)

Granuloma annulare is defined by necrobiosis, meaning degeneration of collagen in the dermis, surrounded by a ring of palisading histiocytes and often with mucin deposition in the degenerated area. This collagen degeneration with a palisading granulomatous appearance is the hallmark histologic pattern.

Caseating granulomas would point to infections like tuberculosis or certain fungi, not granuloma annulare. Spongiosis refers to intercellular fluid buildup in the epidermis, typical of eczema, not a dermal granulomatous process. Epidermal atrophy is thinning of the epidermis, which is not the characteristic finding here.