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

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.