Author: Dr Harriet Cheng, Dermatology Registrar, Waikato Hospital, Hamilton, New Zealand; Duncan Lamont, Pathologist, Waikato Hospital, Hamilton, New Zealand; A/Prof Patrick Emanuel, Dermatopathologist, Auckland, New Zealand, 2014.
Erythema gyratum repens is a clinically distinctive figurate or annularerythema that is usually associated with underlying malignancy. The eruption is rapidly migrating and composed of concentric rings forming a wood-grain pattern.
Histology of erythema gyratum repens
Histological features of erythema gyratum repens are not diagnostic and include hyperkeratosis, parakeratosis, acanthosis and spongiosis. There may be perivascular lymphohistiocytic infiltrate in the papillary dermis (Figure 1, arrow shows parakeratosis).
Histological differential diagnosis is broad as features are quite nonspecific. Fortunately the clinical appearance is distinctive. Biopsy may be undertaken to exclude clinical differentials including erythrokeratoderma variabilis, resolving pityriasis rubra pilaris, bullous pemphigoid and epidermolysis bullosa aquisita.