Onkologie. 2013:7(2):78-82

Histological changes in malignant melanoma of the eye following radiotherapy with CyberKnife

Jana Dvořáčková^1,2, Jirka Mačák^1,2, Petr Mašek³, David Feltl⁴, Jana Žmolíková^1,5

¹ Ústav patologie Lékařské fakulty Ostravské univerzity

² Ústav patologie Fakultní nemocnice Ostrava

Radiosurgery with CyberKnife is used in the treatment of uveal melanomas in some cases. Histological and immunohistological changes

in tumour tissue following treatment have been addressed by relatively few authors. This paper presents the results of investigations of

two such cases. Enucleation of the eye was performed for painful glaucoma in both patients. Patient 1 had a recurrent melanoma treated

with a Gamma Knife ten years ago. Due to slight progression in the melanoma site, treatment with CyberKnife was used with total doses

of 45 Gy in 3 fractions. Some five months following eye irradiation, there was regression of the recurrent tumour from the original height

of 1.4 mm in an area of 6 mm x 0.6 mm to that of 0.3 mm in an area of 3 mm x 0.3 mm. Histologically, residua of a sparsely cellular locus of

regressively altered tumour cells and the presence of reactive changes in the optic nerve were noted. Patient 2 underwent radiotherapy with

CyberKnife one month prior, with subsequent complicated cataract surgery and enucleation of the eye without regression, i.e. destruction

of tumour cells. The size of the tumour of 11.1 mm x 15 mm with a height of 9.3 mm remained unchanged even after irradiation with a dose

of 40 Gy/1 fr. No pathological changes in the tumour cells were seen on histological examination. In patient 1, immunohistochemistry showed

high diffusion expression of the bcl-2 protein of up to 75 % and less than 1 % positivity on examination with the proliferation marker

Ki-67. In patient 2, the situation was different, with significant, as high as 75 % positive expression of the bcl-2 protein in tumour cells in the

superficial tumour layers and a decreasing rate of positive expression in the deep tumour layers where it reached no more than 25 %. The

proliferation activity with positive nuclear expression of Ki-67 increased from the surface, where it ranged from 1 % to 3 %, to the depth of

the tumour and toward its base, where it reached up to 5 %. Our observation suggests significant redistribution of genetic activity within

the tumour. It is manifested by overexpression of the bcl-2 protein and, in patient 2, different bcl-2 protein positivity in the various tumour

layers is apparent. The relation of this phenomenon to radiotherapy remains unclear.

Keywords: Malignant uveal melanoma, therapy with CyberKnife, enucleation of the eye, regressive tumour changes

Published: May 1, 2013  Show citation