DIAGNOSTIC AND THERAPEUTIC CHALLENGES OF POSTERIOR SCLERITIS MIMICKING CHOROIDAL MELANOMA

Abstract

Introduction:  Posterior scleritis is a rare form of scleritis. Posterior scleritis occur in 2-12% of cases of scleritis, 64,4-71,1% occur in female. Its clinical features may be confused with choroidal pathologies like choroidal melanoma. Posterior scleritis is 1,5% from 400 lesions simulating choroidal melanoma. This case report presents a diagnosis and therapeutic challenges of posterior scleritis mimicking choroidal melanoma. Diagnosis is made based on history taking, complete ophthalmology examination and ancillary test.

Case Report: A-49-years-old woman came to outpatient clinic with gradual vision loss and ocular pain. She has history of hypothyroid disease. Her visual acuity (VA) was 6/15 in the right eye and 6/9,5 in the left eye. Posterior segment examination revealed disc oedema. B-Scan Ultrasonography showed choroidal thickening without T-sign. She was diagnosed with posterior scleritis and received systemic corticosteroids. At 4-month follow-up her VA was 6/60 in the left eye, exudative retinal detachment was found on funduscopy, B-Scan Ultrasonography showed hyperechoic subretinal mass with overlying subtenon fluid reflection. In a month, B-Scan Ultrasonography on left eye showed larger nodular mass with characteristic T-Sign, OCT macula showed subretinal fluid and MRI showed thickening of left posterior sclera. Posterior scleritis was identified, then the patient received oral methotrexate and high dose corticosteroid. At 2-weeks follow-up, VA on left eye improved to 6/18 and exudative retinal detachment has resolved. B-Scan ultrasonography showed scleral thickness was decreased but T-sign still exist.

Discussion: Posterior scleritis can mimic choroidal melanoma, the diagnosis of posterior scleritis is based on clinical presentation, eye examination and ancillary testing. B-scan ultrasound is useful for confirming posterior scleritis. Posterior scleritis can be treated with steroid or combination of steroid and antimetabolite if steroid treatment fails or inflammation recurs after tapering the steroids.

Conclusion: Posterior scleritis has variable clinical presentation and it may mimic choroidal melanoma. High suspicion clinical assessment combined with ancillary testing are essential for diagnosis. Combination of steroid and antimetabolite therapies are useful in cases with inadequate response to steroid alone.