Light micrograph of tissue infected with Madurella grisea fungus (centre). The fungus has formed a granule composed of fungal hyphae embedded in a cement-like matrix. M. grisea granules have a characteristic dark outline. Found in soil and water, M. grisea can cause fungal mycetoma (eumycetoma), an infection of the subcutaneous tissue (deepest layer of skin). The proliferating fungus causes purulent swellings and boils. In later stages destruction of deeper tissues may occur, causing deformity and loss of function. Treatments include long-term antifungal medication.