BLUE NEVUS AND ITS DISTINCTION FROM MONGOLIAN SPOT AND THE NEVUS OF OTA

[摘要] Histo-logic studies were made in 200 cases of blue nevi. The common type occurs chiefly on the dorsal surface of the extremities and the majorities of lesions are from 2 to 10 mm. in diam. The cellular type of blue nevus, which can be diagnosed histologically only, is dense and is larger in size than is the common type. Blue nevi in the form of plaques are uncommon. The histo-pathologic picture of blue nevus is diagnostic. Some question remains concerning the origin of the blue-nevus cell. The blue-nevus cell can be distinguished from the cells of ordinary pigmented nevi; no lesion occurred in which both types of nevus were present. The blue-nevus cell is also to be found in Mongolian spot and the nevus of Ota. Transitional states between blue nevus and these 2 latter conditions may occur clinically and histologically. Three cases of metastasizing cellular blue nevi are reported but in none of these has death occurred. Two cases of nevus fusco-caeruleus ophthalmo-maxillaris of Ota are reported; in the first of these, metastasis and death resulted within 3 yrs., whereas in the second, extensive local growth was present when the patient was last seen. As in ordinary pigmented nevi, the blue nevus and its variants usually run a benign course and do not require surgical removal except for cosmetic purposes or when the lesion is situated in a region exposed to repeated trauma, friction or irritation. When malignant melanomas arise in blue nevi, they are usually preceded by a change to the cellular type of blue nevus.