Imaging characteristics of idiopathic scleroma: a retrospective case series and review of the literature.

Background: Idiopathic scleroma (previously coined solitary idiopathic choroiditis or focal scleral nodule) is an innocuous lesion affecting the sclera with intraocular manifestations. It is often the basis of many misdiagnoses such as amelanotic choroidal melanoma, osteoma or metastatic lesions. Patients are often asymptomatic and the course is benign. With increasing use of community based imaging, more of such cases are being identified. This paper is a retrospective case series investigating the multi-modal imaging findings of idiopathic scleroma.

Methods: A retrospective analysis of prospectively collected data were analysed. Over the course of January 2008-January 2022, 44 patients diagnosed with idiopathic scleroma and imaged with wide-field colour fundus photography, fundus autofluorescence, ocular coherence tomography (OCT) and B-scan ultrasonography. Due to a poor image, only 43 images were included for OCT review. We also reviewed our patient's demographics, symptoms and baseline ophthalmic characteristics upon presentation.

Results: The mean age was 52 years (range 32-79) and there was no predilection towards gender. All lesions were post equatorial with the most common location being inferotemporal (n = 16, 36%); 32 lesions (73%) were yellow on fundus photography. 82% (n = 36/44) of lesions exhibited hyperautoflourescence and 43 lesions (98%) showed hyperechogenicity on B-scan ultrasonography. 100% of lesions originated from the sclera with no lesions showing active inflammation. 20 (47%) lesions had associated blood vessels overlying them on OCT.

Discussion: Idiopathic scleroma is a yellow, hyperautofluorescent, hyperechogeneic scleral lesion that has no signs of active inflammation. These characteristics help define them from other more sinister cause of amelanotic fundal lesions.