Combined Hamartoma of the Retina and RPE
A combined hamartoma of the retina and RPE is not a true neoplasm but may present as a tumorous growth in the eye. It is characterized clinically by a slightly elevated, variably pigmented mass that involves the RPE, peripapillary retina, optic nerve, and overlying vitreous (see Chapter 17, Fig 17-14C). Frequently, a preretinal membrane that distorts the tumor’s inner surface is present. The lesion is often diagnosed in childhood, supporting a probable hamartomatous origin. However, the vascular changes can be primary, with secondary changes in the adjacent RPE.
Figure 11-51 Combined hamartoma of the retina and RPE. A, Low-magnification photomicrograph showing thickening of the peripapillary retina, increased vascularity with variably sized blood vessels (arrows), and cystic change in the outer plexiform layer (asterisks).B, Thickening of the optic nerve head and peripapillary retina with a fibroglial membrane on the optic nerve surface (between arrowheads). Box with dashed line is shown at higher magnification in part C. Smaller box is shown at higher magnification in part D. C, Hyperplastic RPE surrounding small blood vessels (arrows) in the peripapillary nerve fiber layer. D, Small-caliber vascular channels (arrows) and hyperplastic RPE (arrowheads) in the optic nerve head.
(Courtesy of Robert H. Rosa Jr, MD.)
Histologically, the tumor is characterized by increased thickness of the optic nerve head and peripapillary retina, with an increased number of blood vessels (Fig 11-51). The RPE is hyperplastic and frequently migrates into the retina in a perivascular distribution. Vitreous condensation and fibroglial proliferation may be present on the surface of the tumor.
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.