Botryomycosis Secondary to Staphylococcus simulans Masquerading as Mycetoma in a 46-year-old Filipino Female

Botryomycosis is a rare pyogenic disease that presents with chronic suppurative and granulomatous skin lesions, commonly caused by <i>Staphylococcus aureus</i>. We report a case of botryomycosis presenting similarly to mycetoma, secondary to the emerging cutaneous pathogen <i>Staphylococcus simulans.</i> A 46-year-old female who previously worked in a wet market presented with a 13-year history of suppurative papules on a gradually enlarging right foot, and pain on ambulation. She had no systemic symptoms or co-morbidities, and does not recall preceding trauma. Physical examination showed brawny edema of the right foot with multiple sinus tracts draining purulent discharge. The clinical diagnosis at presentation was mycetoma. Magnetic resonance imaging showed a soft tissue mass involving the right foot and ankle with osseous destruction. Biopsy revealed suppurative granulomatous dermatitis; staining with Grocott methenamine silver did not highlight fungal elements. Potassium hydroxide mount of the purulent discharge did not show grains or hyphal elements. Tissue cultures showed growth of co-trimoxazole-susceptible <i>Staphylococcus simulans</i>. The patient was managed as a case of botryomycosis and treated with co-trimoxazole for 12 months. There was a significant decrease in right foot circumference along with scarring and resolution of associated pain. Repeat biopsy showed no evidence of infection. This is the first reported case of botryomycosis in the Philippines as well as the first report citing <i>Staphyloccocus simulans</i> as a causative agent. Botryomycosis is an important differential in patients clinically presenting as mycetoma. Animal pathogens may need to be considered as etiologic agents in at-risk patients with chronic subcutaneous infections.