Presumed solitary circumscribed retinal astrocytic proliferation (pSCRAP) is a rare retinal tumor typically located posterior to the equator of the eye. In previously reported cases, vision is not affected by the lesion, as it is often outside the macula and discovered incidentally.1
pSCRAP needs to be differentiated from retinal astrocytic hamartoma, which arises from the retinal nerve fiber layer and can be associated with tuberous sclerosis and similar systemic findings.2 Multimodal imaging can be helpful to establish the diagnosis. Optical coherence tomography (OCT) demonstrated that pSCRAP is located in the deep neurosensory retina with an intact nerve fiber layer and shadowing of the deeper structures.1,3 Bruch's membrane can sometimes be visualized deep to the lesion. Fluorescein angiography often shows early hypofluorescence with late staining, and these lesions are typically found to be hypo- or iso-autofluorescent. Recently, Shields et al. suggested that the name “retinal astrocytic proliferation” may be incorrect, as most astrocytes reside in the nerve fiber layer, which appears to be spared in these lesions.3
OCT angiography (OCTA) is a relatively recent addition to the armamentarium of retinal imaging. To date, no reports of the OCTA findings of pSCRAP have been published, nor have cases arising in the fovea.
A 74-year-old woman was referred for a retinal abnormality in her right eye with a possible diagnosis of adult-onset foveomacular vitelliform dystrophy. The patient had a normal medical history and denied any recent change in vision, though she did describe the right eye had been blurry centrally since her mid-40s. Her corrected visual acuity was 20/250 in the right eye and 20/25 in the left eye. She noted central distortion with wavy vertical and horizontal lines on Amsler grid testing of the right eye.
On examination, the anterior segment was unremarkable other than a well-centered intraocular lens. The posterior exam in the right eye was notable for a hypopigmented nodule in the central macula with surrounding retinal pigment epithelial changes (Figure 1A). No cystoid edema or hemorrhage was noted. Multimodal imaging showed hypoautofluorescence, late staining on fluorescein angiography, and sparing of the nerve fiber layer on spectral-domain OCT with the lesion appearing to arise from the RPE or deep retina in a derby hat configuration (Figures 1B–1D). These findings were consistent with previously described pSCRAP lesions.
(A) Color fundus photography of the right eye shows a pearl-white central retinal lesion. (B) Spectral-domain optical coherence tomography of the right eye reveals a hyperreflective lesion with sparing of the overlying retinal nerve fiber layer that is hypoautoflourescent (C), as well as stains without leakage on fluorescein angiography (D).
OCTA was performed using the Zeiss Cirrus 5000 (Carl Zeiss Meditec, Dublin, CA). OCTA shows an intact inner capillary plexus overlying the lesion, and no intrinsic vascularity to the lesion itself (Figure 2A). The vasculature around the lesion was intact and did not appear to be anastomosing into the lesion (Figures 2B–2D).
(A) Optical coherence tomography angiography (OCTA) of the inner retina shows vascular flow to the central lesion. (B) OCTA of the deep retina does not show any flow of the deep capillary plexus into or toward the lesion. (C,D) OCTA of the choriocapillaris and choroid show blockage from the lesion of the underlying blood flow.
pSCRAP is an uncommon benign retinal tumor. It is typically located posterior to the equator but outside the central macula and, thus, is often asymptomatic and detected incidentally. In this case, the lesion was located in the central macula, and the patient had markedly decreased vision. This led to the consideration of alternative diagnoses, including astrocytic hamartoma, hypopigmented retinal pigment epithelial adenoma, and solitary idiopathic choroiditis. The clinical features and multimodal imaging, however, were most consistent with pSCRAP. These include the lesion's pearl-white coloration, the abrupt way it arises from the surrounding retina (derby-hat configuration), its smooth edges, the sparing of the overlying nerve fiber layer, and the subtle retinal pigment epithelium (RPE) changes surrounding the lesion. The patient was a poor historian, but noted that her vision declined in her 40s, suggesting that the lesion was not congenital in nature.
The central retina is supplied by both superficial and deep vascular networks. The superficial capillary plexus primarily supplies the retinal ganglion cells, whereas the deeper plexus surrounds the inner nuclear layer. These layers can be visualized with OCTA using the automated segmentations on commercially available platforms. To the extent that the automated segmentation does not properly follow the true boundaries between the superficial and deep vascular plexuses,4 manual adjustments can be performed.
OCTA adds additional information to the understanding of pSCRAP. The blood vessels in the superficial capillary plexus appear to be intact overlying the lesion in the compressed nerve fiber layer, which was spared on the structural OCT (Figure 2A). Though hyperreflectivity on structural (B-scan) images can lead to projection artifacts and blocking of the deeper layers of the retina and choroid on OCTA, there does not appear to be any intrinsic vascularity in the lesion itself on OCTA. Similarly, the vascular pattern surrounding the lesion does not show any evidence of vascular flow entering into the lesion itself. Given the lack of structural abnormality surrounding the lesion, the automated segmentation of the retinal layers on OCTA is likely correct. These findings support the hypothesis advanced by Shields et al. that the name pSCRAP is likely a misnomer, and the lesion is the result of a fibrotic process, perhaps arising from the RPE or glial cells, and not retinal astrocytes.3
As OCTA technology improves, including through the use of swept-source technology, which may allow for better depth of penetration, additional insights may be learned regarding the origins of this uncommon lesion.
- Shields JA, Bianciotto CG, Kivela T, Shields CL. Presumed solitary circumscribed retinal astrocytic proliferation: The 2010 Jonathan W. Wirtschafter Lecture. Arch Ophthalmol. 2011;129(9):1189–1194. doi:10.1001/archophthalmol.2011.211 [CrossRef]
- Schwartz SG, Harbour JW. Spectral-domain optical coherence tomography of presumed solitary circumscribed retinal astrocytic proliferation versus astrocytic hamartoma. Ophthalmic Surg Lasers Imaging Retina. 2015;46(5):586–588. doi:10.3928/23258160-20150521-13 [CrossRef]
- Shields CL, Roe R, Yannuzzi LA, Shields JA. Solitary circumscribed “pearl white” retinal mass (so-called retinal astrocytic proliferation) resides in deep retina or beneath retina: Findings on multimodal imaging in 4 cases. Retin Cases Brief Rep. 2017;11(1):18–23. doi:10.1097/ICB.0000000000000278 [CrossRef]
- Spaide RF, Curcio CA. Evaluation of segmentation of the superficial and deep vascular layers of the retina by optical coherence tomography angiography instruments in normal eyes. JAMA Ophthalmol. 2017;135(3):259–262. doi:10.1001/jamaophthalmol.2016.5327 [CrossRef]