The clinical and histopathologic features of a poorly recognized malformation of the optic disc are described. Typically, the otherwise asymptomatic patient has a blind eye requiring enucleation either because of pain from secondary glaucoma or for cosmetic reasons. An atypical clinical presentation occurs in more than one quarter of the cases when enucleation is undertaken for suspected intraocular tumor. The distal region of the optic nerve is externally enlarged, corresponding to a localized colobomatous defect in the optic disc. Microscopically, striking lipomatosis of the leptomeninges of the distal optic nerve, combined with heterotopic smooth muscle in the peripapillary sclera and choroid, is seen in the region of the coloboma at the disc. Infrequently the colobomatous defect is more extensive, involving the sclera, choroid, and retina well away from the disc.
Willis R, Zimmerman LE, O'Grady R, Smith RS, Crawford B. Heterotopic Adipose Tissue and Smooth Muscle in the Optic DiscAssociation With Isolated Colobomas. Arch Ophthalmol. 1972;88(2):139-146. doi:10.1001/archopht.1972.01000030141003