[Surgical grafting of malignant human melanomas into athymic nu/nu mice : macroscopic and microscopic study].

Tissue from 5 human malignant melanomas was surgically grafted into 39 athymic mice, 20 on lombar muscles covered by their aponevrosis, 13 on the intraperitoneal surface of the abdominal wall, 6 between the dorsal muscles and rib cage. These encapsulated, non-infiltrating, non-destructive tumours were clinically, macroscopically and histologically benign, but cytologically they have a malignant aspect. These were no perceptible visceral, cutaneous or muscular metastases. It would seem that a phenomenon of loosing of invasivness and destruction appeared. However further studies with other tumours and different experimental conditions will be needed to confirm the existence of this phenomenon.