Macrophomina phaseolina infection
The most common presentation of M phaseolina infection, in 3 of the 4 patients, was a soft tissue infection. One patient presented with a painful, edematous toe with purulent discharge, another with an ulcerated soft tissue mass on the foot, and the third with a tender, erythematous nodule above the ankle that later ulcerated and became necrotic. The fourth patient experienced traumatic inoculation of the eye with M phaseolina leading to fungal keratitis in an immunocompetent patient, which presented as ocular pain and decreased visual acuity with periorbital edema, conjunctival congestion, corneal epithelial defects, and hypopyon.
Three of the four patients who acquired the infection were immunocompromised, with underlying conditions such as diabetes, solid organ transplant, and malignancy. Three cases occurred in individuals of Asian ethnicity (Indian-American, Indian, and Sri-Lankan Canadian), and 2 patients affected had recently traveled to India.
There have been no reported cases of disseminated M phaseolina infection.
B36.9 – Superficial mycosis, unspecified
14560005 – Dermal mycosis
Differential Diagnosis & Pitfalls
- Cutaneous blastomycosis – A violaceous, verrucous lesion with occasional ulceration and heaped-up borders. Microscopy reveals broad-based budding organisms. Endemic areas include the Mississippi and Ohio River basins.
- Cutaneous coccidioidomycosis – Cutaneous granulomatous lesions or subcutaneous soft tissue abscesses. Endemic areas include the western United States, Mexico, and South America.
- Cutaneous histoplasmosis – May present as a slow-growing nodule that ulcerates and develops heaped-up margins. Endemic areas include the Mississippi and Ohio River basins, the Caribbean, and southern Mexico.
- Mycetoma – A tumor-like mass or edematous plaque, typically on the foot, with communicating sinuses and fistulae that actively drain purulent material and granules that vary in color from white through yellow and red to black.
- Venous insufficiency ulcer – A shallow ulcer with irregular borders and fibrinous exudate over a wound bed that most commonly affects the skin above the medial malleolus. While mild to moderately painful, these ulcers do not overlie a soft tissue mass as in M phaseolina infection. Additional signs of venous insufficiency, such as varicosities, edema, and brown discoloration of the lower extremities, are often present.
- Arterial insufficiency ulcer – An exquisitely painful ulcer with well-demarcated borders and overlying necrotic eschar that usually occurs distally on the toes or on pressure-bearing areas of the foot. Patients may have diminished or absent peripheral pulses and a history of intermittent claudication.
- Neuropathic ulcer – A painless, well-demarcated ulcer that occurs on pressure-bearing areas of the foot. Patients will have a history of peripheral neuropathy, most commonly due to diabetic neuropathy, and absence of sensation in the involved areas on physical examination.
- Pyoderma gangrenosum – Begins as a pustule and rapidly progresses to a painful ulcer with necrotic, undermined borders. More commonly occurs in patients with a systemic disorder such as inflammatory bowel disease or rheumatoid arthritis.
- Medium vessel vasculitis