Mycetoma of the calf due to Nocardia brasiliensis

Mycetoma is an indolent tumor-like process of soft tissue caused by fungi (eumycetoma) and actinomycetes (actinomycetoma). Nocardia brasiliensis is the most common etiology of actinomycotic mycetoma, especially in Mexico [1,2]. The organism is found in the soil but occasionally has been isolated from animals [1]. An injury, usually involving the lower extremities, often precedes the development of the painless, locally invasive, and indolent infection [3]. The incubation period ranges from 1 week to several months [1]. Hallmarks of the process include tumefaction, draining sinuses, and the presence of grains in the purulent drainage that represent microcolonies of the organism [3]. Prolonged courses of antibiotic therapy are required, but recurrences may still occur [3-8].