[Pathological and ultrastructural changes in conjunctival malignant melanoma treated by cryotherapy]

The liquid nitrogen cryotherapy was used to treat conjunctival malignant melanoma. Light and transmission electron microscopic examinations were carried out before, during and after the treatment. It was discovered that the tumor cells died within a few minutes after the cryoapplication. Under transmission electron microscope, marked necrosis of tumor cells was seen 10-14 days after the treatment and a large amount of collagenous fibers and fibroblast hyperplasia were seen in the tumor in 3-4 weeks following the application, while the tumor cells were seldom found. Under light microscope, as significant necrosis of the malignant melanoma occurred, the surface conjunctival epithelium gradually grew and covered the defect of the conjunctiva, showing that the malignant melanoma cells are much more sensitive to the cryoapplication than the normal conjunctival epithelial cells.