Further evidence for increased light sensitivity in patients with malignant melanoma.

Minimal erythema dose (MED), immediate pigment darkening (IPD) and skin typing were performed on 130 patients with malignant melanoma and on seventy-three controls. The tumours were histologically classified according to Clark as superficial spreading melanoma, nodular melanoma, and lentigo maligna melanoma. The tumours of twelve patients were not possible to classify. Patients belonging to skin type IV and patients with lentigo maligna melanoma had a significantly higher mean age. The IPD reaction was significantly higher in skin type II than in skin types III and IV both in patients and in controls. IPD and MED showed no significant correlation to age and sex. MED was significantly lower among patients with malignant melanoma than controls. These data indicate that light sensitivity is of aetiological importance in malignant melanoma.