Conjunctival stromal tumour (COST): anterior-segment OCT findings

Abstract

Conjunctival stromal tumour (COST) is a recently described rare conjunctival tumour of mesenchymal origin with only four publications describing a handful of cases thus far. In this report, we describe the anterior-segment optical coherence tomography (AS-OCT) characteristics in a case of COST for the first time, in addition to the clinical and histopathological characteristics. The AS-OCT showed an elevated, dome-shaped hyporeflective homogenous lesion in the conjunctival stroma lined by hyperreflective outer layer with mild posterior shadowing, consistent with histological description of a paucicellular tumour with large myxoid collagenous material inside. Immunohistochemistry showed positive CD34 and vimentin but negative S100 and smooth muscle actin, thereby differentiating it from conjunctival myxoma.

Conjunctival Stromal Tumor: Report of 2 New Cases and Review of the Literature

“…Including our cases, to date a total of 22 clinicopathologically well-characterized cases of COST have been reported (Table 1). [1][2][3][4][5][6] The lesions have occurred sporadically in patients of different age groups ranging from 11 to 66 years old (mean age = 45 years; median age = 46 years), mixed ethnicity (possibly more common in Chinese/Asian population), and a male-to-female ratio of 1.2:1. The majority of patients presented with a slowgrowing solid mass or cyst-like lesion, often asymptomatic or with slight conjunctival irritation/foreign body sensation; however, one case demonstrated rapid growth and was large enough to cause exotropia.…”

“…5 Benign conjunctival cysts are the major clinical differential diagnosis of COST; however, cystic lesions tend to transilluminate on clinical examination, and can be easily distinguished by histopathologic assessment. 1,6 Other reported clinical mimics include ocular surface squamous neoplasia, benign or neoplastic lymphoid infiltrates, and ocular sarcoid, although none of these are considered as a differential diagnosis at the microscopic level. 2 The main histologic differential diagnosis is "conjunctival myxoma," which can be associated and an early manifestation of "Carney complex" in a subset of cases.…”

“…1,2 COST appears to be an extremely rare tumor, and to date, only 20 cases have been published in the literature showing a limited range of clinical manifestations with unifying histopathological and immunohistochemical findings, distinguishing this entity from its mimics. [1][2][3][4][5][6] In this report, we describe 2 additional cases of COST and review the previously published cases in an attempt to encapsulate the clinical and demographic characteristics and to expand the immunomorphological property of this emerging entity.…”