Rhinosporidiosis
Rhinosporidium seeberi, closely related to several protoctistiae fish pathogens, was previously thought to be a fungus and has never been propagated in vitro. It is the cause of chronic granulomatous inflammation in the mucosa (although recent studies suggest waterborne cyanobacterium Microcystis aeruginosa as the causative organism), presenting as vascular, friable nasal polyps. The disease is endemic in the Indian subcontinent and Sri Lanka and has been reported in the United States.
1 minute clinical correlation