Pythium insidiosum: A Rare Necrotizing Orbital and Facial Infection.

Pythium insidiosum, also known as "swamp cancer," has been long known for its destructive effects on plants and animals. Infections with this fungus-like organism typically occur in temperate, tropical, and subtropical regions [ 1]. Human infection with P insidiosum, although exceedingly rare, is characterized by invasion of the cornea, cutaneous, subcutaneous, and orbital tissues with eosinophilic, tumor-like masses demonstrating arterial tropism [ 1, 2]. In most cases, patients have a history of recent exposure to wet environments [ 1]. If left untreated, P insidiosum is fatal, because it is an angioinvasive organism that leads to thrombosis and tissue ischemia. Reports of most human cases are from Thailand, with only 4 well documented orbital cases to date in the United States and Australia [ 1, 3, 4].