**3.11 Choroidal macrovessel**

It is a rare ocular lesion which appears on fundus examination as an abnormal, tortuous vessel deep to the retina. It was first described as a serpiginoid atrophic lesion in the temporal macula, with an orange-red aspect and several unspecific choroidal spots in the posterior pole [81]. Choroidal macrovessel is not associated with acute inflammation and symptoms. Some reports have shown hyperpigmentation of the RPE, debris in the subretinal space, and changes in the outer nuclear layer (ONL) thickness [82, 83]. SD-OCT reveals a tubular structure which shows hyperreflectivity band below RPE representing the superior edge of the lesion, with an elevation of RPE and photoreceptor and posterior shadowing [81]. In recent studies, it has been explored with enhanced-depth imaging spectral domain optical coherence tomography (EDI SD-OCT) showing a vascular structure that traversed the entire choroidal thickness and produces an indentation at the choroidal-scleral junction and the ellipsoid zone (EZ) causing a reduction of the ONL thickness [82, 83]. A differential diagnosis from choroidal macrovessel should be made with subretinal nematode tract, choroidal hemangioma, inflammatory choroidopathy, retinochoroidal anastomosis, vortex varix, and aberrant long posterior ciliary artery [81, 83].
