Differential Diagnosis of Polypoidal Choroidal Vasculopathy
The key conditions that mimic polypoidal choroidal vasculopathy (PCV) include neovascular age-related macular degeneration (nAMD), central serous chorioretinopathy (CSC), pachychoroid neovasculopathy, and other causes of subretinal neovascularization—each distinguished by specific imaging findings and patient demographics.
Primary Differential Diagnoses
Neovascular Age-Related Macular Degeneration (nAMD)
- Key distinguishing features: Presence of drusen, typically in older patients 11
- Imaging: Neovascular lesions visible on OCT, OCT-A, FA, and ICGA 1
- Choroidal characteristics: Thinner choroid compared to PCV; PCV demonstrates significantly greater subfoveal choroidal thickness than nAMD 2
- Critical pitfall: PCV can present with concurrent non-polypoidal neovascularization, making differentiation challenging 11
- The absence of polypoidal dilatations on ICGA and OCT is the definitive differentiator 11
Central Serous Chorioretinopathy (CSC)
- Clinical overlap: Both conditions can present with serous retinal detachments and RPE changes 3
- Key differentiators:
- Critical diagnostic point: In CSC with persistent/recurrent exudation, multiple RPE changes can evolve that closely mimic PCV—ICGA is essential for differentiation 3
- Common misdiagnosis scenario: Multiple variably-sized serous PEDs in PCV can masquerade as CSC 3
Pachychoroid Neovasculopathy (PNV)
- Distinguishing features: Neovascular network over areas of choroidal thickening and thickened Haller's layer vessels ("pachyvessels") 11
- Imaging: Neovascular network visible on ICGA, FA, and OCT-A 1
- Choroidal comparison: PNV demonstrates even greater choroidal thickness than PCV 2
- Treatment overlap: Both respond to anti-VEGF and/or photodynamic therapy 1
Secondary Differential Diagnoses
Other Neovascular Conditions
- Chorioretinal atrophy adjacent to optic disc
- Oblique optic disc insertion
- Thin choroid (opposite of PCV's thick choroid)
- Deep retinal red-brown bands
- Often bilateral with early onset
- Associated with pseudoxanthoma elasticum
- Optic disc drusen present
- Yellow-white punched-out round spots deep to retina
- Predominantly affects women under 50 years
- Yellow-white subretinal streak
- History of blunt ocular trauma
Vitelliform Lesions
Best Vitelliform Macular Dystrophy 1:
- Positive family history, bilateral symmetrical disease
- Hyperautofluorescence on FAF
- No focal leakage on FA, no choroidal hyperpermeability on ICGA
- Absent/markedly decreased light rise on electro-oculography
Adult-Onset Foveomacular Vitelliform Dystrophy 1:
- Small (<1 disc diameter) round foveal yellowish subretinal lesions
- Central hypofluorescence with hyperfluorescent ring on FA
Diagnostic Algorithm
Step 1: Clinical Assessment
- Age and ethnicity (PCV more common in elderly Asians) 45
- Fundoscopic examination for orange polyp-like structures (hallmark of PCV) 6
- Look for "serosanguineous retinopathy" pattern 6
Step 2: Essential Imaging
- ICGA is the gold standard for identifying polypoidal dilatations 114
- OCT to assess for polypoidal lesions, branching vascular network, and subfoveal choroidal thickness 14
- OCT-A for neovascular network visualization 4
- FA to evaluate leakage patterns and exclude other diagnoses 1
Step 3: Key Differentiating Features
- Presence of polypoidal dilatations on ICGA/OCT = PCV 11
- Drusen + neovascularization without polyps = nAMD 1
- Focal leakage without polyps + younger age = CSC 3
- Thick choroid with pachyvessels but no polyps = PNV 1
Critical Clinical Pearls
- The subretinal polyp-like structure has the highest odds ratio (28) for PCV diagnosis 6
- Scar formation has an odds ratio of 0 for PCV, making it a negative predictor 6
- PCV can present simultaneously with CNM, requiring careful multimodal imaging 7
- Without ICGA, PCV is frequently misdiagnosed as CSC or nAMD 38
- Subfoveal choroidal thickness in PCV is intermediate: greater than nAMD and healthy controls, but less than CSC and PNV 2