New interpretations in rhinosporidiosis, enigmatic disease of the last nine decades.

Fungal etiology is widely quoted for the disease rhinosporidiosis. Identity of the fungal sporangium and its relationship with the disease have baffled medical scientists and mycologists for several decades. This study provides unequivocal evidence against involvement of fungus in rhinosporidiosis. The so-called sporangium is found to be a unique body containing residue-loaded lysosomal bodies ('spores') for elimination from the system. 'Sporangia' have been redesignated nodular bodies (NB) and 'spores' as spheres of cellular waste (scw). Two carbohydrates, namely defective proteoglycans synthesized intracellularly and an exogenous polysaccharide ingested through diet of tapioca constitute indigestible material in NB and scw. Polysaccharide in NB which has beta, 1-4 glycosidic bonds between mannose residues is not degraded by gastrointestinal enzymes nor in intracellular lysosomes which break only alpha-glycosidic bonds. A link between NB and dry tapioca has been deduced. Rhinosporidiosis is a complex phenotype with perhaps no parallel in medical science. This report erases 99 years (1892-1991) of controversies regarding 'causal organism' of rhinosporidiosis.