Halo dermatitis around tumours.

Circular dermatitis around different benign or malignant lesions were examined in 19 patients. The morphological picture was the same whether it occurred around an acquired naevus cell naevus, a congenital naevus cell naevus, a seborrheic keratosis, a stucco-keratosis, a keloid, a benign lentigo, an insect bite, a basal cell carcinoma, or a squamous cell carcinoma. The central lesions were macroscopically unaffected by the surrounding inflammation.