Benign Lobular Inner Nuclear Layer Proliferation associated with Congenital Hypertrophy of the Retinal Pigment Epithelium

Purpose: To report two cases of benign intraretinal tumors of the inner nuclear layer (INL) associated with congenital hypertrophy of the retinal pigment epithelium (CHRPE). Methods: Multimodal imaging of two cases, including fundus color and autofluorescence photography, structural and en face spectral-domain optical coherence tomography (SD-OCT), OCT-angiography, fluorescein and indocyanine green angiography. Results: During a routine examination, intraretinal tumors of the INL associated with several CHRPE lesions were observed in one eye of two male patients, aged 27 and 32 years, respectively. Multimodal imaging showed white multifocal lobulated lesions with arching extensions, located in the INL, which allowed diagnosing benign lobular inner nuclear layer proliferation (BLIP). Conclusion: BLIP is a rare benign tumor located in the INL with a unique pattern and only 4 cases have been reported to date. The present two cases allowed confirming that BLIP is associated with CHRPE, suggesting a concomitant developmental anomaly of the RPE and the inner retina.