Hemorrhagic Bacillary Layer Detachment in Macular Telangiectasia Type 2.

Abstract

Macular telangiectasia Type 2 (MacTel 2) is a bilateral disease characterized by neurodegenerative and vascular changes affecting the fovea.1 The occurrence of subretinal neovascularization in MacTel 2 is rather rare but constitutes a vision-threatening complication.2 We describe longitudinal multimodal imaging features of a novel variant of bacillary layer detachment (BLD, outer retinal split at the level of the photoreceptor inner segment myoid)3 and termed “hemorrhagic BLD” in a case of subretinal neovascularization associated with MacTel 2. This report followed the tenets of the Declaration of Helsinki. A 55-year-old woman presented with proliferative MacTel 2. Fundus photography showed active yellowish neovascular membrane with subretinal hemorrhages (Figure 1A). Optical coherence tomography (OCT) angiography segmented at the level of the outer retina confirmed subretinal neovascularization (Figure 1B). Optical coherence tomography disclosed a parafoveal outer retinal cyst consistent with BLD and adjacent subretinal fluid (Figure 1, C–E). The higher optical intensity in the BLD compared with that of subretinal fluid and its colocalization with subretinal hemorrhage on fundus photography suggested heme accumulation in the BLD. Eye-tracked follow-up OCT performed one month after a single intravitreal injection of ranibizumab (0.5 mg/0.05 mL) demonstrated significant regression of the BLD (Figure 1, F and G). Persistent focal attenuations of the ellipsoid and interdigitation zones were noted.Fig. 1.: Multimodal imaging features of hemorrhagic bacillary layer detachment. A. Color fundus photography shows typical features of macular telangiectasia Type 2 including retinal graying, crystalline deposits, ectatic capillaries, and hyperpigmentation foci. There is an active yellowish neovascular membrane (white arrowhead) with subretinal hemorrhages. B. Optical coherence tomography angiography segmented from the outer retina to the choriocapillaris shows a subretinal neovascular membrane (white arrowhead). The inset shows segmentation lines of the en face optical coherence tomography angiography image with red flow signal overlay. C–E. The (C) is a magnified view of the BLD on OCT as illustrated in (E). The intraretinal split occurs at the level of the hyporeflective myoid zone (green arrowheads). The ellipsoid zone (orange arrowhead) of the attached retina is continuous with a faint hyperreflective line (orange arrowhead) that likely represents split photoreceptor inner segments and outer segments remaining adherent to the retinal pigment epithelium/Bruch membrane complex (yellow arrowhead). The external limiting membrane (blue arrowheads) is visible over the top of the BLD (withe arrowhead). Note the dense hyperreflective material within the BLD that corresponds to heme accumulation and may interfere with accurate delineation of the outer retinal layers. The (D) is the near infrared reflectance image with the green line indicating the position of the OCT scan. Vertical OCT scan (E) shows parafoveal outer retinal cyst consistent with BLD (white arrowhead) and adjacent subretinal fluid (asterisk). F and G. Eye-tracked follow-up near infrared reflectance image (F) and OCT scan (G) performed 1 month after an intravitreal injection of ranibizumab shows dramatic resolution of the BLD. The external limiting membrane is intact. Note the persistent focal attenuations of the ellipsoid and interdigitation zones (between red arrowheads).To the best of our knowledge, hemorrhagic BLD has not been associated with proliferative MacTel 2, although similar findings coined “atypical outer retinal fluid accumulation” have been reported in neovascular age-related macular degeneration.4 Intense leakage of fluid from the subretinal neovascularization and modulation of the adherence between photoreceptor outer segments and retinal pigment epithelium by the subretinal hemorrhage may have induced BLD development.5 In fact, fibrin interdigitation between photoreceptor outer segments has been documented after experimental subretinal hemorrhages and may explain the presumed photoreceptor fracture under hydrostatic pressure effect.