Chondrodermatitis nodularis chronica helicis.

23 clinically and pathologically typical lesions of chondrodermatitis nodularis chronica helicis occurring in 19 patients are reviewed. The lesions seem to fit well with the clinical and pathologic findings of diseases of transepidermal elimination. Clinically, one finds exceedingly chronic tender nodules of the ear with a central horny plug. Histologically, there is epidermal hyperplasia around an area in the upper dermis which displays fibrinoid material and/or necrobiotic collagen with the formation of a sinus tract through the epidermis. Although the derangement of the collagen in the upper dermis seems to be the inciting factor in producing transepidermal elimination, other factors such as anatomy, vascular deficiency and trauma are also important in pathogenesis.