Furuncular myiasis from Dermatobia hominis infestation. Diagnosis by light microscopy.

Myiasis, the infestation of humans or other vertebrates with fly larvae, may appear as furuncular nodules. Furuncular myiasis occurring in the Western hemisphere, especially in Central and South America, is usually caused by Dermatobia hominis infestation. Travel history, gross examination, and histologic evaluation of the submitted fly larvae will allow the clinician and dermatopathologist to identify the causative organism. We report two cases of furuncular myiasis due to Dermatobia hominis and review the clinical and histopathologic findings pertinent to its diagnosis. In addition, we attempted to identify some of the cardinal internal structures of this organism by extrapolating known information about insect internal anatomy and physiology to the structures visualized during serial transverse sectioning of the larvae.

Pseudallescheria boydii mycetoma in northern New England.

Mycetoma is a chronic subcutaneous fungal infection characterized by tumefaction, draining sinuses, and grains. It is most common in the tropics but occasionally occurs in the United States. We report a case of a mycetoma affecting the foot of a 38-year-old mentally retarded man from northern New England. The causal organism was identified as Pseudallescheria boydii, the most common cause of mycetoma in the United States. The patient showed a partial response to 8 months of ketoconazole therapy.