A rare case of double recurrent choroidal melanoma, with distinctive immunohistochemical features

A 57-year-old woman, with left choroidal melanoma treated by laser photocoagulation and a history of repeated vitrectomies, checked for left eye acute pain and foreign body-like sensation, symptoms that occurred after three years since the primary tumor treatment. The left eyeball was enucleated and the tissues were investigated by immunohistochemistry for markers associated with cell differentiation, proliferation and adhesion, cell cycle regulation, apoptosis control, vascularization, invasiveness and local immune response. We identified, in fact, two independent tumors, with different localization and sharing some common features, markers of a highly aggressive potential: loss of cell differentiation markers and cell cycle regulators, ability to avoid death by suppressing Fas antigen expression and important invasive capacity by down regulation of E-cadherin expression. However, only in the posterior tumor, we found cells with high proliferation rate, Fas ligand molecule expression and MMP-9 secretion, acquisitions associated with a much more aggressive behavior. These particular phenotypes allowed the posterior cells to grow and to invade the surrounding tissues more rapidly than the anterior ones, leading to the development of a large size tumoral mass, responsible for the clinical symptoms. Photocoagulation, by destroying the tissues, makes impossible the evaluation of the primary tumor's biological features, important for the tumor evolution. The absence of these data stresses the importance of patient monitoring, eventually addressing a panel of soluble markers associated with recurrence or metastasis development.