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Guinea pig cutaneous nevi transplanted to athymic nude mice: a potential model for benign and malignant melanocytic lesions.

Junctional and compound pigmented nevi, induced by 9,10-dimethyl-1,2-benzanthracene in the skin of albino guinea pigs, were transplanted as split- and full-thickness grafts to athymic nude mice. This experiment was designed as a feasibility study to establish a model in which junctional nevi could be kept outside the donor organism for prolonged periods. Different methods of securing grafts and promoting their survival were used in 19 mice. Mice died or were killed between 15 and 178 days after grafting. Histology revealed that the grafts survived in 11 mice. Nevus cells were found in six mice. The time from grafting to the observation of nevus cells did not exceed 68 days. All nevi showed slight to advanced features of degeneration and disappearance. Poor survival of the guinea pig epidermal portion of the graft and a host cellular reaction appeared to be the main reasons why nevi had a tendency to disappear from the athymic nude mouse skin.