[Occupational chronic arsenical poisoning. On the cutaneous manifestations (author's transl)].

A physical examination with detailed dermatological examination was made on 28 Japanese male workers, 22 to 63 years old, who had been exposed to arsenic for one to 24 years, in processes manufacturing lead arsenate, calcium arsenate and so on to be used as insecticides. Many corn-like punctate keratoses were seen on the palms and soles of 7 workers. The histopathological features in 6 specimens of punctate keratoses of palms and other regions of 4 workers were hyperkeratosis, acanthosis and elongation of rete ridge, but no malignant changes, although there were mild disorderly arrangements in part of stratum malpighii. Multiple lesions of sharply demarcated dullred patch with scale were found on the trunk and extremities of 3 workers. These lesions histopathologically showed the typical feature of Bowen's disease. Characteristic bronze pigmentation on the trunk and extremities was seen in 6 workers, and 5 of these 6 workers showed tiny normal or depigmented skin (raindrops) throughout the involved areas. These corn-like punctate keratoses mainly on the palms and soles, multiple Bowen's disease and diffuse bronze pigmentation with raindrop areas of hypopigmentation on the trunk and extremities were manifest almost in the same individuals, and it was concluded that they were characteristic cutaneous symptoms of chronic arsenical poisoning. There was no correlation between the intensity of cutaneous manifestations and the term of exposure to arsenic. Cutaneous manifestations due to arsenic were generally recognized as follows: diffuse pigmentation appears at first in one to two years after exposure to arsenic, then punctate hyperkeratotic lesions appear mainly on the palms and soles, and Bowen's lesions occur after several years or more. The use of arsenic has been abandoned in this factory since January, 1971. Diffuse bronze pigmentation now seems to be considerably lightened, as long time has passed after exposure to arsenic. However, since punctate hyperkeratotic lesions on the palms, soles and others may, though rarely, undergo malignant transformations, new lesions of Bowen's disease may further occur and these lesions may develop to invasive squamous cell carcinoma, physical examinations of the workers exposed to arsenic should be continued and careful observation of them is necessary for the future.