Eumycetoma

Background

• Also known as “mycotic mycetoma” and "Madura foot"
• Chronic subcutaneous fungal skin and soft tissue infection
• Caused by many different types of molds
• Infection occurs following inoculation of conidia into skin or subcutaneous tissue
• Usually confined to subcutaneous tissue but can spread to fascia, bone, and lymph nodes via continguous dissemination

Microbiology

• There are at least 41 organisms capable of causing eumycetoma
• Most frequent pathogens include
  • Madurella mycetomatis
  • Nigrograna mackinnonii
  • Trematosphaeria grisea
  • Falciformispora senegalensis
  • Scedosporium apiospermum

Clinical Features

Madura foot.

• Located in uncovered areas that have been traumatized (mostly feet, legs, and hands)
• Most often affects lower extremities (typically a single foot)
• Characteristic triad is tumor, sinus tracts, and macroscopic grains
• Progression
  • Initial lesions are painless, often begin as slowly growing indurated subcutaneous nodules
  • Extension occurs due to nodule swelling and coalescence, resulting in large tumors that can evolve into necrotic abscesses with sinus tracts
  • May progress over months to many years
  • Can extend from skin and subcutaneous tissue to muscle, bone, and lymphatic vessels
• Pain is usually associated with secondary bacterial infection

Complications

• Fibrosis
• Ankylosis
• Lymphedema
• Joint destruction

Differential Diagnosis

• Actinomycosis
• Botryomycosis
• Nocardiosis
• Foreign body granuloma
• Soft tissue tumor
• Cyst
• Folliculitis
• Sporotrichosis
• Chromoblastomycosis
• Cutaneous leishmaniasis
• Cutaneous tuberculosis
• Elephantiasis
• Podoconiosis

Evaluation

Plain x-ray of Madura foot.

• Physical exam looking for characteristic triad (tumor, sinus tract, and macroscopic grains)
• Microscopy of grains using 20% potassium hydroxide solution
• Gram stain can be considered to evaluate for alternative diagnoses
• Deep biopsy with culture
• Imaging: CT or MRI (although MRI more sensitive) to determine bony involvement and extent of soft tissue involvement
• PCR can be done to evaluate for specific causative pathogens

Management

• Extended antifungal therapy, depending on causative agent, generally at least 12 months (3 months after clinical and radiographic resolution)
  • Possibilities include itraconazole, voriconazole, posaconazole
• Surgery is not first line as relapse rates are high (109),if performed it should be done in conjunction with antifungal therapy

Disposition

• Disposition will depend on severity of lesion and overall clinical status of patient
• Providers should consider possibility of secondary bacterial infection