Peripapillary astrocytic hamartomas evolve from the optic nerve.

Astrocytic hamartomas are rare benign tumours. Spectral domain optical coherence tomography (SD-OCT) with advanced visualisation (optic disc cube 200×200) was performed on a 27-year-old man with peripapillary astrocytic hamartomas in the right eye. En face (OCT scan) view (CT scan) of the optic nerve at the level of retinal pigment epithelium revealed optic nerve fibres along with three associated areas showing optical shadowing corresponding with astrocytic hamartomas in continuum. An area of optical shadowing was also observed superiorly in the retinal tissue corresponding with another astrocytic hamartoma. Astrocytes in diffusely vascularised rat retina have been reported to be immigrants from the optic nerve. En face SD-OCT-based in vivo histology for the first time provides strong evidence that peripapillary astrocytic hamartomas are derived from optic nerve astrocytes.