Posterior Corneal Pigmentation and Fibrous Proliferation by Iris Melanocytes

Peripheral Pigmented Placoid Corneal Endotheliopathy

“…[1][2][3][4][5][6][7][8][9][10] The common neoplasms include benign cystic tumors, anterior segment melanocytoma, and uveal melanoma. [11][12][13][14] Here, we report 4 cases of peripheral pigmented placoid corneal endotheliopathy (PPPCE) in otherwise healthy eyes without a history of preexisting trauma, inflammation, intraocular surgery, or tumors.…”

Clinical, histopathological and immunohistochemical characterization of a novel equine ocular disorder: heterochromic iridocyclitis with secondary keratitis in adult horses

“…Clinical and histopathological evidence of uveitis suggests that the RFM develop as a result of inflammatory exudates, which have organized to form a membrane or induce endothelial metaplasia . In humans, retrocorneal pigmentation is the result of endothelial phagocytosis of free melanin, pigment‐laden macrophages adhered to the endothelium, or the presence of iris melanocytes and/or iris pigmented epithelium on the inner cornea . Iris melanocytes can proliferate on the corneal endothelium and produce fibrilar material (basement membrane) and collagen through a metaplastic process …”

“…16 In humans, retrocorneal pigmentation is the result of endothelial phagocytosis of free melanin, pigment-laden macrophages adhered to the endothelium, or the presence of iris melanocytes and/or iris pigmented epithelium on the inner cornea. 18,19 Iris melanocytes can proliferate on the corneal endothelium and produce fibrilar material (basement membrane) and collagen through a metaplastic process. 19 Moderate to severe lymphoplasmacytic panuveitis with macrophages observed in HIK differs substantially to that of ERU, which is characterized by predominantly a lymphoplasmacytic infiltrate with formation of iris follicles.…”

Brown cornea

“…Primary corneal melanoma does exist [14], and it may be caused by invasion of the corneal stroma of tumour cells from adjacent conjunctival, ciliary body, and iris melanoma [10] or from acquired conjunctival melanosis with atypia [8,9,12]. Corneal pigmentation is frequently due to trauma and drug side effects [4], and may also rarely be caused by migration of iris melanocytes covering the Descemet's membrane [2,5,11,13]. Pigment granules may be phagocytosed by endothelial cells, but in such cases the corneal stroma seems not to harbour pigments [6].…”