Clinical and histopathological aspects in two cases of ligneous conjunctivitis.

Ligneous conjunctivitis represents a very rare form of chronic membranous conjunctivitis, with unknown etiology; less than 200 cases have been reported in the literature, most of them in infants and children. After 40 years, this condition appears in exceptional circumstances. We present, in this study, two patients (of 55 and 64 years old) with very severe forms of ligneous conjunctivitis, certified by histopathological examination, one of them being previously diagnosed with Lyell's syndrome. The histological examination in ligneous conjunctivitis is important for diagnostic but also to elucidate the etiopathological context. A discontinued hyperplastic conjunctiva with numerous nuclear abnormalities and marked intra- and inter-cellular edema was characteristic for both cases. The epithelium layer presents large area of extension into the connective tissue, in the form of cysts and gland-like structures, or creating deep epithelial lacunas, with goblet cells. The connective subepithelial tissue presents diffuse inflammatory infiltration, with round cells, especially near vessels. Inside the conjunctival tissue, big hyaline areas with rare cellularity are detected. The amorphous deposits containing fibrillar material are also present. At the level of pseudo-membranes, we recorded a massive exudation of fibrin with an inflammatory cellular infiltration, and large areas containing an amorphous eosinophilic hyaline material. The association of ligneous conjunctivitis with Lyell's syndrome in one of our patients suggests its immuno-allergic etiology.