Subacute zygomycosis of the orbit.

A zygomycotic (phycomycotic) orbital cellulitis developed in a healthy 9-year-old boy. Because of the involved tissue's unfamiliar histopathologic features, an initial diagnosis of eosinophilic granuloma was made and appropriate treatment was delayed for more than six months. The patient's slowly progressive form of zygomycosis was clinically and morphologically similar to that described in previously recorded cases. All three cases occurred in otherwise healthy children living within the United States. Their involved tissues had mixed histopathologic features of chronic granulomatous entomophthoramycosis and acute necrotizing mucormycosis; however, unlike entomophthoramycosis, the fungi in these cases may invade the walls of blood vessels and cause severe tissue necrosis. We believe that these three cases represent a distinct clinicopathologic variant of facial-cranial zygomycosis not previously delineated in the literature. Although they are aggressive, these infections are not as fulminant as in classic mucormycosis, but can nevertheless be lethal.