Torpedo maculopathy is characterized by a unilateral, oval-shaped region of chorioretinal hypopigmentation, resembling a “bullet” or a “torpedo” and located temporal to the macula.1 Two types of this idiopathic and congenital condition have been described in literature:2 type 1, presenting with an attenuation of the outer retinal structures but no outer retinal cavitation; and type 2, with both attenuation of the outer retinal structures and outer retinal cavitation. However, no histopathological studies of this particular lesion are currently available in literature to date. Generally stable over time, torpedo maculopathy may rarely complicate with the development of choroidal neovascularization (CNV).3,4 Hereby, we describe a case of CNV associated with torpedo maculopathy diagnosed and studied by means of multi-modal imaging tools, including spectral-domain optical coherence tomography (OCT) (Spectralis HRA; Heidelberg Engineering, Heidelberg, Germany), fundus fluorescein angiography, indocyanine green angiography (ICGA) (Spectralis HRA; Heidelberg Engineering, Heidelberg, Germany), and OCT angiography (OCTA) (DRI Triton OCT; Topcon, Tokyo, Japan).
A 36-year old white woman complaining of a dark spot in her left visual field but with negative past medical history was referred to our center (Department of Ophthalmology – Ospedale San Raffaele, Milan, Italy). Written informed consent was obtained for identifiable health information included in this case report. Her visual acuity (VA) was 20/20 in both eyes. Anterior segment and intraocular pressure were within normal limits. Biomicroscopic fundus examination of the right eye was normal, but a chorioretinal hypopigmented lesion with hyperpigmented wedge-shaped “tail” extending temporally was evident in the left perifoveal region (Figure 1A). OCT examination of this exact area detected the presence of a choroidal excavation with severe disruption of all the outer retinal layers and slight marginal retinal pigment epithelium hyperplasia. Based on the absence of outer retinal cavitation (Figure 1D), this presentation was judged consistent with type 1 torpedo maculopathy.
Multimodal imaging of a patient with torpedo maculopathy. The typical aspect of this maculopathy is shown on a color fundus photograph (A); the green arrow indicates the scan present on optical coherence tomography (OCT) (D–E). Fundus fluorescein angiography (B) displays some hyperfluorescent signal, primarily attributable to partial staining of the lesion and to interdigitation zone attenuation, whereas late phases of indocyanine green (C) disclose a faint staining on the lesional border. Structural OCT scan instead reveals focal choroidal excavation corresponding to the torpedo-like lesion with disruption of the ellipsoid zone and of the interdigitation zone; moreover, retinal pigment epithelium hyperplasia can be noticed on the border (yellow arrowhead). Angio B-scan (E) shows some visible flow above the retinal pigment epithelium (orange arrowhead).
Although fluorescein angiography did not show any sign of leakage in both early and late phases (Figure 1B), ICGA disclosed some unspecific perilesional staining on the temporal edge, especially visible in the late phase (Figure 1C). Likewise, a 3 mm × 3 mm OCTA scan centered on the torpedo-shaped fundus lesion revealed a small, abnormal, vascular network in proximity to its temporal border (Figures 2C–2E), with rarefaction of the corresponding choriocapillaris layer (Figure 2D). In addition, a fine rarefaction at the deep capillary plexus was noticed, whereas the superficial capillary plexus was overall unaffected (Figures 2A and 2B).
Optical coherence tomography angiography (OCTA) of the torpedo lesion compared with the other angiographic techniques. Although the superficial (A) and the deep (B) capillary plexuses do not show significant vascular alterations on a 3 mm × 3 mm OCTA scan, a clear rarefaction is evident in the choriocapillaris (D). Interestingly, few small capillary tufts are noticed in the outer retina segmentation (C, yellow star). The same macular region is shown in a magnified fashion on fluorescein and indocya-nine angiographies (E and F, respectively).
Patients with torpedo maculopathy generally maintain good VA with limited visual field defect in the affected eye. However, the progression toward macular atrophy or the development of neovascular lesions may bring about further visual deterioration over the follow-up. Although OCTA features in torpedo maculopathy have been previously described,5 our case report is able to demonstrate for the first time how swept-source OCTA can promptly detect the occurrence of complications in this disease (eg, abnormal vascular network), thus conferring a tangible advantage over both fundus fluorescein angiography and ICGA. In addition, hyperautofluorescent areas have been described in presence of ellipsoid and interdigitation zones attenuation,5 making the identification of CNV challenging on fluorescein angiography. The focal vascular rarefaction observed at the choriocapillaris supports the hypothesis of an aberrant choroidal circulation underlying the pathogenesis of torpedo maculopathy; in this scenario, the development of an abnormal vascular network might represent a secondary degenerative complication following the choroidal vascular anomaly. Moreover, we speculate that timely detection of these vascular anomalies might hence open unexpected therapeutic windows to the use of anti-vascular endothelial growth factor treatment.
In conclusion, we recommend that patients affected by torpedo maculopathy undergo OCTA to rule out for the presence of ongoing neovascular processes, particularly in case of visual decline, and to monitor and study the possible evolution of these idiopathic chorioretinal lesions in time.
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