HISTOPATHOLOGICAL FINDINGS IN HUMAN CHOROIDAL MELANOMAS AFTER TRANSPUPILLARY THERMOTHERAPY

Aims-The effect of transpupillary thermotherapy (TTT) on human choroid al melanomas was investigated by means of histopathology. Methods-Befo re enucleation TTT was performed in 11 eyes with a xenon are photocoag ulator with a red filter or a diode laser at 810 nm. The exposure time was 1 minute; the estimated temperature at the top of the tumour was about 65 degrees C. Results-Seven of 11 tumours developed necrosis to a maximum depth of 3.9 mm with a sharp demarcation between the necroti c and the viable part of the tumour. The depth correlated with penetra tion of heat into the tumour. Scattered small haemorrhages in the tran sitional zone between the necrotic and the viable part of the tumour w ere observed in three eyes but large haemorrhages were absent. Ocular media were not affected owing to the low rate of absorption of radiati on at 810 nm. TTT did not cause significant scleral damage. Intrascler al tumour cells with a viable appearance were observed in one eye, whe re the tumour was almost totally necrotic. Conclusion-Results show tha t TTT has potential as a conservative therapeutic treatment for choroi dal melanomas.