An unusual case of Epstein-Barr virus driven lymphoproliferative disorder of the conjunctiva which mimicked a high grade lymphoma: a sheep in wolf's clothing

Macrodendritic ulcerative keratitis and conjunctival lymphoid hyperplasia in horses with equine herpesvirus-2 and equine herpesvirus-5 infections

OBJECTIVE

The aim of this study was to describe the clinical, confocal microscopic, histologic, and virologic features of horses with macrodendritic ulcerative keratitis and conjunctival lymphoid hyperplasia associated with equine herpesvirus-2 and equine herpesvirus-5 infection.

ANIMAL STUDIED

Four foals with bilateral ocular disease.

PROCEDURES

Complete ophthalmic examination was performed for each horse, and corneal samples were collected for cytology and microbiologic evaluation, including virus isolation and molecular diagnostics for the equine herpesviruses. In vivo confocal microscopy examination of the cornea was performed in two horses. Conjunctival biopsies for histopathology were collected from two horses with nodular conjunctival thickening.

RESULTS

Each horse had bilateral, large, superficial dendritic corneal ulcerations that covered extensive regions of the corneal surface. Corneal in vivo confocal microscopy examination in two horses detected inflammatory cells and populations of morphologically abnormal corneal epithelial cells adjacent to the ulcerations. The abnormal epithelial cells included round, relatively small, hyperreflective cells intermixed with elongated, enlarged, hyperreflective cells. Equine herpesvirus-2 was isolated from corneal samples of 2 horses and detected by PCR assay in the other two horses. Equine herpesvirus-5 was also detected by PCR assay in three of the horses. Conjunctival histopathology identified predominantly lymphocytic infiltrates. The macrodendrites and conjunctival masses resolved with topical antiviral therapy (cidofovir or idoxuridine) in all horses and did not recur.

CONCLUSIONS AND CLINICAL RELEVANCE

The equine gammaherpesviruses may be associated with the development of macrodendritic ulcerative keratitis and conjunctival lymphocytic masses in foals. In vivo confocal microscopy of horses with macrodendrites revealed similar findings to other host species with herpetic dendritic keratitis.

Anterior segment involvement in Epstein-Barr virus: a review

The aim of this study is to describe the involvement of Epstein-Barr Virus (EBV) in the diseases of the ocular anterior segment. This is a narrative review designed using the PUBMED, SCOPE and Web of Science databases, searching for reported literature on findings in the anterior ocular segment related to EBV between 1990 and 2020. Epstein-Barr Virus (EBV) is implicated in the development of salmon-coloured conjunctival masses in the context of acute mononucleosis and lymphoproliferative disorders. Moreover, EBV can cause haemorrhagic conjunctivitis and its corneal implications appear as different types of keratitis patterns. The involvement of EBV in the pathogenesis of anterior segment inflammation is not well-defined. Current evidence regarding anterior segment disease caused by EBV infection has been proved by positive viral detection through polymerase chain reaction test in eyes with lymphoproliferative disorders known to be caused by EBV, as B- and NK/T-cell lymphoid tumours. Antiviral treatment (oral Aciclovir or Valaciclovir) in anterior segment disease caused by EBV remains controversial.