[Case report of a severe Mooren's ulcer].

Mooren's ulcer is a painless and idiopathic ulcer of the peripheral cornea related to autoimmunity against a corneal stromal antigen, calgranulin C. Corneal involvement is isolated. There are no specific histopathological features to differentiate Mooren's ulcer from pseudo-Mooren's, the latter being part of a systemic disease. Mooren ulcer is a diagnosis of elimination based on a complete etiological check-up. However, histopathological examination, when performed, could provide additional data to support the diagnosis. We report the case of a 78-year-old female patient who presented with Mooren's ulcer. The patient had complained of red eye and photophobia for two weeks. Initial visual acuity was "counting fingers". Clinical examination revealed a perforated perilimbic ulcer with an iris prolapse. Based on the peripheral ulcerative keratitis, with a negative etiological work-up and anatomopathological analysis of the cornea, the diagnosis of Mooren's ulcer was proposed. This rare case illustrates the need for a multidisciplinary approach involving ophthalmologists, pathologists, and internists, to reach a diagnosis and optimize the functional prognosis.