Atypical histiocytic granuloma with eosinophilia.

Atypical histiocytic granuloma in the oral mucosa has recently been described as a benign non-neoplastic ulcero-proliferative lesion of histiocytic origin with eosinophilia. The disease is confined to the oral mucosa where the lesion is solitary. These lesions, which heal spontaneously, are not associated with systemic disease or dissemination. This report deals with such a case, and it stresses the benign nature of the lesion despite the worrying clinical and microscopic appearance. The morphological diagnosis was substantiated by the use of a series of immunohistochemical reactions.