Cervicofacial mycetoma

Actinomyces israelii is a gram-positive, anaerobic, filamentous branching rod that is normal oral flora; it becomes pathogenic when mucosal breach allows entry into deeper tissue. The hallmark 'lumpy jaw' is a slowly enlarging, woody-hard swelling at the angle of the mandible that crosses tissue planes and fascial boundaries without regard for anatomical barriers, eventually forming sinus tracts to the skin. The discharged sulfur granules are yellow macroscopic colonies of organisms, not sulfur. The critical exam contrast is with Nocardia: Actinomyces is anaerobic, not acid-fast, forms sulfur granules, causes cervicofacial and abdominal disease, and is treated with high-dose penicillin for months, whereas Nocardia is aerobic, partially acid-fast, causes pulmonary and central nervous system disease in the immunocompromised, and is treated with trimethoprim-sulfamethoxazole. Actinomyces is also associated with pelvic infection in the setting of intrauterine devices. Surgical drainage and prolonged antibiotics are both usually required.