Clinical and histopathologic findings after photodynamic therapy of choroidal melanoma

Photodynamic therapy (PDT) has been used occasionally as an alternative treatment for uveal melanomas. The present study describes the clinical and histopathologic features of five choroidal melanomas after PDT.

Three patients with pigmented choroidal melanomas were treated with PDT and intravitreal bevacizumab 1 week before undergoing biopsy and brachytherapy to minimize the risks of bleeding during the biopsy. Another two patients received PDT as a primary treatment for peripapillary amelanotic melanomas, one of them also in combination with bevacizumab.

The tumors treated with PDT and bevacizumab showed a marked reduction in tumor vascularity assessed by indocyanine angiography, and the biopsies were conducted without recognizable bleeding, showing viable tumor cells. The tumors receiving PDT as a primary treatment were followed by progressive tumor growth that led to enucleation years after. The histopathology revealed overlying fibrosis with invasion of sclera and optic nerve.

Photodynamic therapy and bevacizumab can induce closure of the superficial vasculature of a pigmented choroidal melanoma, but in none of our cases, there was evidence of tumor destruction from this treatment. Preoperative PDT may be useful to reduce the potential of bleeding at the time of tumor biopsy. Our cases do not support the use of a single session of PDT as a primary treatment for pigmented small choroidal melanomas.