Confocal Scan Imaging and Impression Cytology of the Cornea in a Case of Multiple Endocrine Neoplasia Type-2b

A 19-year-old female who was a known case of multiple endocrine neoplasia (MEN) type 2, presented with gradual decrease of visual acuity in her left eye and bilateral corneal opacities which had developed over a 7 month period. She had nocturnal lagophthalmos since childhood, and history of a thyroid mass with increased serum levels of calcitonin for which subtotal thyroidectomy had been performed. The histopathologic diagnosis of the thyroid mass had been medullary thyroid carcinoma. Best corrected visual acuity was 20/25 and 20/40 in her right and left eyes, respectively. Slit lamp biomicroscopic examination, photography using a photo slit lamp (Haag-Streit BQ900, Switzerland), and corneal confocal scan imaging (Confoscan 3.4, Nidek Technology, Padova, Italy) were performed. Since we suspected limbal stem cell deficiency, impression cytology was also performed on both eyes. Slit lamp examination in both eyes revealed moderate thickening of the eyelid margins, meibomian gland dysfunction, gelatinous and worm-like subconjunctival masses in the perilimbal area suggestive of neuromas (Fig. 1A), nonspecific vascularized opacification of the inferior cornea which was more severe on the left side (Fig. 1B), and prominent intrastromal medullated nerves with an irregular lacy pattern across more than half of the cornea (Fig. 1C). Intraocular pressure and fundus examination were unremarkable. Although the patient had signs of meibomian gland dysfunction, she did not have dry eye symptoms. Since we were suspicious of limbal stem cell deficiency as one of the possible factors in the development of corneal opacities, impression cytology was performed bilaterally which disclosed mild epithelial squamous metaplasia of the involved areas, but no signs of limbal stem cell deficiency (Fig. 1D). Confocal scanning of central, paracentral