SKIN LESIONS touched the nape of the neck. Neck lesions are illustrated in Plate 1-4. Axillary lesions (Plate 11) usually consisted of coalescing papules. Antecubital fossa lesions were characterized by formation of thickened plaques. Several babies and one womandeveloped lesions in the anal region which, though not deep, were painful due to excoriation of the epidermis. These healed rapidly. Deeper lesions were seen on the scalp, neck, feet, and in one case on the ear. They were char- acterized by transepidermal necrosis with wet desquamation leaving weeping, crusting ulcerations. Vesiculation was not observed except with foot lesions which developed bullae, frequently several centimeters in diameter, beneath thickened pigmented plaques. These foot lesions occurred on the dorsum ‘of the feet and between the toes. (Only one case showed des- quamation on the soles of the feet.) After several days the bullae ruptured and desqua- mated leaving raw ulcers. Some of these lesions, particularly of the feet, became secondarily infected requiring antibiotics. However, most of the lesions healed rapidly and new epithelium covered the ulcerated areas within a week to 10 days. Foot lesions are illustrated in Plates 5-10. Oneear lesion (Plates 13-16) took several months to heal. The repigmentation of some deeper lesions presented abnormalities. Neck lesions often developed a dusky, grayish brown pigmentation associated: with a thickened “orange peel” ap- pearance. Histological appearance of epidermal rugosity was also noted in these lesions (see section on histopathology). In addition, the deeper lesions of the feet failed to repigment, remaining pink or white. At examination 6 months and 1 year after the exposure, the skin appeared normal with no residual changes in the vast majority of cases. However, some of the deeperlesions continued to showevidence of residual damage. Foremost among these was the ear lesion which had healed with considerable scarring, atrophy, scaling of the epidermis and gross telangiectasis. By 6 months the hyperpigmentation and thickening of the skin of the neck lesions had greatly subsided and by 1 AND EPILATION 31 year pigmentation changes were mild. Foot lesions had not repigmented at sites of deepest involvement and some atrophy of the skin in these areas was apparent. 3.32 Microscopic Appearance Biopsies were taken of seven neck, and one axillary lesion in the Rongelap group during the third to fourth week after exposure. At the time of biopsy these lesions were in the hy- perpigmented stage with little or no desquamation. Most of the biopsies were taken from individuals with lesions of average severity. A second series of biopsies (repeats in three in- dividuals) were taken from this group, 4 at the seventh week and 5 at the eighth week postexposure. These were taken from the neck and antecubital fossae. All of these lesions had desquamated and the depigmented skin had re- pigmented to a dusky, gray color with some thickening of the skin (“orange-peel” appearance), plates 25 and 27. Biopsies were not taken from ulcerative lesions or from the feet because of the danger of infection. A third series of 11 biopsies were taken from the Rongelap group at 6 months along with several con- trol biopsies from unexposed natives. Material was obtained in many cases adjacenttosites of previous biopsies. All biopsy wounds healed rapidly within a week to 10 days with no secondary complica- tions. The microscopic findings are summarized as follows: First series—3rd. to 4th week. Epidermis. Transepidermal damage was noted with a few intervening arcades showing less damage (Plates 21 and 22). The epidermis in the most extensively involved areas showed considerable atrophy with flattening of the rete pegs and in places the epidermis was reduced to a thickness of 2 to 3 cells (Plates 21, 23, and 24). Thecells of the malpighian layer showed pleomorphic nuclei, pyknosis and cytoplasmic halos, giant cells and in a few instances multinucleatedcells.