Anterior segment optical coherence tomography, in vivo confocal microscopy, histopathologic, and immunohistochemical findings in a patient with multiple endocrine neoplasia type 2b.

Purpose: To describe clinical, anterior segment optical coherence tomography (AS-OCT), in vivo confocal microscopy (IVCM), histopathologic, and immunohistochemical findings in a patient with multiple endocrine neoplasia type 2b (MEN 2b) syndrome.
Materials and Methods: Retrospective case report of a patient with MEN 2b.
Results: A 31-year-old male diagnosed with MEN 2b presented with eye redness, burning, and visible conjunctival mass in both eyes. The patient's past medical history revealed that he underwent bilateral adrenalectomy and total thyroidectomy. Genetic testing revealed M918T heterozygous mutation in the RET proto-oncogene. Corrected visual acuity was 20/20 in both eyes. Anterior segment examination revealed bilateral thickened lid margins, ectropion, blepharitis, conjunctival injection, temporal and inferonasal subconjunctival lesions with corneal invasion, corneal neovascularization, and marked corneal nerves. AS-OCT showed a subepithelial mixed reflective lobular mass in both eyes. Hyperreflective and noticeable thickened stromal corneal nerves were observed on IVCM in the left eye. After incisional biopsy of the right perilimbal lesions, histopathological examination revealed that lesions consisted of spindle cells in hypocellular bundles with no atypia and mitosis. Immunohistochemical examination revealed diffuse staining with S100, focal staining with synaptophysin, and no staining with neurofilament protein. These findings were considered compatible with a benign nerve sheath tumor, probably schwannoma.
Conclusions: We present clinical, AS-OCT, IVCM, histopathological, and immunohistochemical findings in a patient with MEN 2b. To our knowledge, this is the first case of a conjunctival schwannoma diagnosed histopathologically in MEN 2b.