A Case of Corneal Neovascularization Misdiagnosed as Total Limbal Stem Cell Deficiency

Abstract

Purpose: To report a case of corneal neovascularization misdiagnosed as total limbal stem cell deficiency (LSCD).

Methods: This is a case report of a 61-year-old woman who has a history of bilateral idiopathic scleritis, keratitis, and uveitis for more than 20 years. She was diagnosed with total LSCD in her left eye based on clinical presentation alone and was confirmed as a candidate for limbal transplantation at several major tertiary eye care centers in the United States. After referral to the Stein Eye Institute, in vivo confocal microscopy (IVCM) and anterior segment optical coherence tomography (AS-OCT) were performed to clarify the diagnosis.

Results: Slit-lamp examination of the left eye revealed 360-degree severe thinning at the limbus and peripheral corneal pannus and neovascularization that spared the central cornea, a smooth epithelium without fluorescein staining at the central cornea, an uneven surface, and pooling of fluorescein at the peripheral cornea accompanied by minimal fluorescein staining of the sectoral peripheral epithelium. IVCM showed that epithelial cells in the central cornea exhibited a corneal phenotype and that the morphology of the epithelium in all limbal regions except the nasal limbus was normal. Epithelial cellular density and thickness were within the normal range. AS-OCT showed severe thinning in the limbus and a normal epithelial layer in the cornea and limbus. Based on the findings of IVCM and AS-OCT, we concluded that the patient had minimal LSCD, and limbal stem cell transplantation was not recommended.

Conclusions: Clinical presentation alone is insufficient to correctly diagnose LSCD in complex cases. Additional diagnostic tests, such as IVCM, are necessary to confirm the diagnosis before any surgical intervention.

Figure 1

Slit-lamp photos and confocal microscopy images of the patient’s left eye. Panels A, D, G, J, and M show images taken under white light. Panels B, E, H, K, and N show images with fluorescein staining. In panels C, F, I, L, and O are confocal images. The central cornea is hazy and edematous and lacks neovascularization (A). The surface of the peripheral cornea is covered by pannus and superficial vessels (panels D, G J, M). The severe scleral thinning is seen within the limbal area. Sectoral epithelial staining is present at the nasal and superior limbus (B, E, H, K, N). Confocal images show that the cellular morphology at the central cornea is normal, which are characterized by small cell size, dark cytoplasm, and distinct cell-cell borders in a regular pattern (C). Conjunctivalized epithelium and goblet cells are found only at the nasal limbus (I). The morphology of basal epithelial cells appears to be normal at the superior, inferior, and temporal limbus (F, L, O).

Figure 2

AS-OCT images of a normal eye, an eye diagnosed with LSCD, and the present patient’s left eye. The corneal epithelium is hyporeflective in the normal eye, with a regular interface between the epithelium and Bowman’s membrane (A). The epithelium thickness at the central cornea is 55 μm in this eye. In contrast, the corneal epithelium is hyper-reflective in the eye diagnosed with LSCD (B), with a decreased epithelial thickness of 37 μm. In the present case described here, the corneal epithelium of the left eye is hypo-reflective, which is similar to that of the normal eye shown in panel A. However, the interface between epithelium and underlying stroma is irregular, with hyper-reflective tissue at Bowman’s membrane, anterior stroma, and deep stroma(C). The epithelial thickness was measured manually at five locations in the central cornea with an interval of 0.5 mm because of subbasal epithelial scarring and the irregular interface between epithelium and stroma. The mean thickness is 54 μm, and the range is 38 μm to 64 μm. There was a severe thinning of peripheral cornea and limbus, with the thickness down to 260 μm (D).