Phenotypic Spectrum of Benign Lobular Inner Nuclear Layer Proliferations: A Multicenter Analysis and Review of the Literature.

Objective: To report the clinical and imaging features of 8 new and 9 published cases with benign lobular inner nuclear layer proliferations (BLIPs).

Design: Retrospective case series and literature review.

Participants: Eight previously unreported patients from 7 institutions internationally and 10 reported cases in the literature.

Methods: Retrospective analysis of clinical and imaging features of BLIPs including systematic review of published cases using relevant terms.

Main outcomes and measures: Description of multimodal imaging and systemic findings in 17 patients with BLIPs.

Results: Eight new cases and 10 previously published cases with BLIPs were reviewed for clinical features, systemic associations, and imaging findings. The tumors were mostly unilateral (16 of 18 cases; 88%), associated with ipsilateral grouped congenital hypertrophy of the retinal pigment epithelium lesions (16 of 20 eyes; 80%), and located posterior to the equator. In all eyes, the tumors were multifocal, and many had curvilinear extensions that extended beyond the central tumor lobules. OCT demonstrated these lesions to be centered within the inner nuclear layer at the border of the inner plexiform layer with no invasion of adjacent layers. Visual acuity was normal (mean: 0.024 logarithm of the minimum angle of resolution; range: -0.01 to 0.3) in all cases, and most patients were asymptomatic. No plausible genetic or systemic associations could be identified.

Conclusions: This expanded series of BLIPs further refines the clinical characteristics and imaging findings associated with this newly described benign retinal tumor.

Financial disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.