In rare instances, very large retinoblastoma tumors can undergo complete and spontaneous necrosis. The mechanism by which spontaneous regression occurs is not well understood, but tumor growth exceeding the vascular supply likely plays a role. The incidence of spontaneous regression is unknown. Children with spontaneous regression can present with vitreous hemorrhage, a dislocated crystalline lens, or phthisis. For this reason, retinoblastoma should be part of the differential diagnosis for young children who present with unilateral phthisis without a history of trauma. The presence of calcification on imaging is highly suggestive of retinoblastoma, and prompt enucleation should be considered. Certain histologic features of the enucleated globe can suggest or confirm the diagnosis.
The vitreous cavity is filled with islands of calcified cells embedded in a mass of fibroconnective tissue.
Close inspection of the peripheral portions of the calcified islands reveals ghosted contours of fossilized tumor cells.
Exuberant proliferation of retinal pigment and ciliary epithelia is present.
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.