Optic nerve choristoma.

We present a case of a 29-year-old female with progressive and complete visual loss in her right eye over a four-year duration. Radiographically, a T2-weighted, bright signal proximal to the optic chiasm was identified (Fig. 1, image A). A right frontal supraorbital craniotomy was performed that revealed a slightly white and congested optic nerve with a gritty consistency. Histopathologic examination demonstrated an admixture collection of benign adipose tissue, smooth muscle elements, and optic nerve tissue, consistent with an optic nerve choristoma (Fig. 1, image B). Immunohistochemical stains for smooth muscle actin (SMA) and glial fibrillary acid protein (GFAP) highlight the smooth muscle component (Fig. 1, image C) and optic nerve tissue (Fig. 1, image D), respectively.

Fig. 1

Choristomas are believed to be developmental malformations of normal, mature-appearing tissues in an abnormal anatomic location. Their presence within the optic nerve is extraordinarily rare, with only few cases having been previously reported in the literature. Histologically, they are characterized by the presence of heterotopic mesodermal elements, chiefly adipose tissue and smooth muscle in close approximation to the optic nerve. Patients often present with a painless, slow and progressive unilateral decrease in visual acuity. Neuroimaging with magnetic resonance (MR) typically shows a hyperintense signal within the optic nerve, characteristic of a fat-containing lesion. Despite their benignity and slow growth, clinical recognition or this rare entity is indicated, as evaluation for surgical decompression may be considered in an attempt to preserve vision.

Conflict of interest

The authors declared that there is no conflict of interest.