Chlamydospores of Rhizopus microsporus var. rhizopodiformis in tissue of pulmonary mucormycosis.

Hyphae are usually the only fungal elements found in tissue of mucormycosis, and other fungal elements are quite rarely encountered. We found chlamydospores in bronchial lumina in autopsied tissue of pulmonary mucormycosis of a diabetic patient. Chlamydospores are thick-walled, asexually produced spores arising from the modification of a hyphal segment. This is the first histologic demonstration of chlamydospores in mucormycosis in which the causative fungus is culturally identified to species level. Rhizopus microsporus var. rhizopodiformis was isolated from the present autopsied pulmonary tissue. A literature review of human infection by this fungus found 27 cases with histopathologic evidence.