A 65-year-old Filipino grape-picker who had lived in California over 40 years developed a mycetoma of the right foot. The causative organism was Madurella grisea. The patient's habit of working barefoot probably afforded opportunity for traumatic implantation of this soil saprophyte into the subcutaneous tissue. Therapy with dapsone over a two-year period appears to have halted the progression of the disease, although signs of activity in the form of abscesses with black grains persist.
Gould WM. Black Grain Mycetoma Originating in Northern CaliforniaReport of a Case Caused by Madurella grisea. Arch Dermatol. 1969;99(4):426-428. doi:10.1001/archderm.1969.01610220054009