Vascularization of choroidal melanomas as a prognostic factor: Comparative analysis between color Doppler and histopathological aspects of tumors

Abstract

Objectives: The objective of the study was to correlate color Doppler with the vascularization of choroidal melanoma (CM) observed in histopathological sections and also to analyze the vascular histopathological prognostic factors of these tumors. Patients, Materials, and Methods: This was an experimental, cross-sectional, and analytical study carried out at Escola Paulista de Medicina - UNIFESP (São Paulo) and at the Ocular Pathology and Translational Research Laboratory of McGill University (Montreal/Canada). Twenty-five enucleated eyes of patients with CM were studied, 10 patients studied at UNIFESP and 15 patients studied at McGill University. The first 10 patients (Brazil), before enucleation, were submitted to color Doppler, all performed at UNIFESP. The resistance index (RI) and maximum systolic velocity of each tumor were calculated. The inclusion criteria of this study were as follows: CMs >8 mm in thickness, enucleation as primary treatment, histopathological blocks sufficient for hematoxylin–eosin staining, periodic acid–Schiff, and CD34 immunohistochemistry. Exclusion criteria included tumors smaller than 8 mm and/or previous treatments such as laser or brachytherapy. Regarding the histopathology of each CM, cell-type classification, vessel diameter measurements, count of the number of mitoses, and vascular clefts were carried out. The latter are considered vessels because they are lined by endothelium (CD34 positive) and surrounded by melanoma cells. Results: There was a statistical correlation between RI and cell type (P < 0.05). Tumors with a better prognosis (spindle cell) showed higher RI compared to epithelioid tumors, with a worse prognosis. The number of mitoses and vascular clefts correlated with the cell type, with a statistically significant difference (P < 0.001). Tumors of worse prognosis (epithelioid) showed an increase in the number of mitoses and in the number of vascular clefts. There was no difference between vessel diameter and cell type. Conclusions: The number of vascular clefts has a positive prognostic correlation with the malignancy of CM. Doppler RI showed a positive prognostic correlation with CM malignancy. For the first time, the usefulness of vascular clefts as prognostic factors was proven, and a new classification of the vascular network in CMs was proposed.