choroidal malignant melanoma /kôroi″dəl/ [Gk, chorion + eidos + L, malignus, ill-disposed; Gk, melas, black, oma, tumor] , a tumor of the choroid coat of the eye that grows into the vitreous humor, causing detachment and degeneration of the overlying retina. Typically mound-shaped or mushroom-shaped, the neoplasm may break through the sclera and appear under the conjunctiva.
