Branched filaments no fungus, ovoid bodies no bacteria: Two unusual cases of mycetoma.

We describe a 58-year-old man presenting with necrotizing panniculitis of the lower right leg and a 64-year-old woman with a clinically similar lesion combined with pustular eruptions and subsequent ulceration on the forehead. In the first patient, Giemsa staining showed small ovoid bodies and Grocott staining revealed hyphae. Histology from the process on the forehead showed branched filaments in the periodic acid-Schiff (PAS) staining. In the first case, Madurella mycetomatis, a fungus, was the pathogenic agent, whereas in the other case white colonies of filamentous organisms resembling fungi could be cultivated that turned out to be the bacterium Nocardia brasiliensis. Since the initial clinical appearance of these two forms of mycetoma were almost identical and histopathologic findings were inconclusive, only sophisticated microbiologic work-up of material from lesional skin led to the correct diagnosis. In times of global tourism, these unusual cases impressively document the necessity to become more familiar with mycetoma to make accurate therapeutic decisions with effective results, possibly saving a limb.