Plume Sign in the Deturgescence of Macular Cysts - A Novel OCT Finding

Abstract

Aim: To describe a novel OCT finding called "Plume sign" in macular cysts.

Methods: Case records of five cases were retrospectively reviewed. Their case history and imaging findings on spectral domain optical coherence tomography (SD-OCT, Spectralis, Heidelberg, Germany) have been described.

Results: We observed five cases which had a solitary cyst foveal or parafoveal in location, was unique due to the presence of a plume-shaped internal substance, was treated with topical NSAIDs and was associated with good visual outcomes. We observed three cardinal events; firstly, retinal thickening followed by the formation of a foveal or parafoveal solitary cyst. Secondly, a vertical expansion of the solitary cysts in an inverted flask-shaped configuration associated with splitting of the retinal layers suggested by a hyper-reflective line and/or a hyporeflective cleft in the outer nuclear layer. Thirdly and finally, a breach of the outer retina with involvement of the external limiting membrane (ELM) and ellipsoid zone (EZ) with an exit trail of proteinaceous material through the defect in the shape of a plume of smoke hyper-reflective on OCT followed by deturgescence of the cyst.

Conclusion: In conclusion, we describe the "plume" sign - a novel OCT finding is cysts and provide a possible pathogenic hypothesis.

Keywords: CME; expansion; fibrin; plume; vertical.