Vascular clefts in choroidal melanoma: Correlation with histopathological prognostic factors

Abstract Objectives: The objectives of this study were to evaluate vascular clefts as histopathological prognostic markers in choroidal melanoma and to correlate their density with established prognostic factors, including tumor cell type, mitotic activity, and tumor size. Patients, Materials, and Methods: This was an experimental, cross-sectional, and analytical study that included 25 patients diagnosed with choroidal melanoma who underwent primary enucleation. Histological samples were obtained from UNIFESP (Brazil) and McGill University (Canada). Hematoxylin–eosin staining was used for mitotic count and cell classification. Periodic acid–Schiff and CD34 immunohistochemistry were performed to identify vascular structures. Vascular clefts were quantified in 20 high-power fields and correlated with tumor cell type, mitotic count, and tumor thickness. Statistical analyses included Spearman’s correlation and the Kruskal–Wallis test. Results: Mixed tumors with epithelioid predominance were the most frequent subtype. A strong positive correlation was observed between the number of vascular clefts and mitotic count (Pearson r = 0.8765; Spearman ρ = 0.8667; P < 0.0001). A significant positive correlation was also found between vascular clefts and tumor thickness (Pearson r = 0.7493; Spearman ρ = 0.8055). Epithelioid tumors demonstrated a significantly higher number of vascular clefts compared with spindle tumors ( P = 0.0019). Conclusions: Vascular clefts are associated with epithelioid cell type, increased mitotic activity, and larger tumor size, supporting their role as markers of tumor aggressiveness. These findings highlight the prognostic relevance of vascular clefts and suggest their incorporation into routine histopathological evaluation of choroidal melanoma.