Eumycetoma (Fungal Mycetoma)

Updated: Oct 20, 2017
  • Author: George Turiansky, MD; Chief Editor: Dirk M Elston, MD  more...
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Overview

Background

Eumycetoma is a chronic cutaneous and subcutaneous infection caused by various genera of fungi. Approximately 40% of mycetomas worldwide are eumycotic as opposed to actinomycotic (ie, caused by bacterial actinomycetes). The disease is marked by progressive destruction of soft tissue and nearby anatomic structures.

Gill, who worked at a dispensary in the southern Indian province of Madura, first recognized mycetomas as a disease entity in 1842. Godfrey first documented a case of mycetoma in Madras, India. Native peoples of the province of Madura commonly called the disease Madura foot. In 1860, Carter, who established the fungal etiology of this disorder, first proposed the term mycetoma. [1] In 1872, Carter further proposed the terms melanoid and ochroid in an attempt to classify the disease into 2 varieties on the basis of the black or pale-colored granules (ie, grains, sclerotia) produced by the etiologic agents. [2]

Note: Opinions or assertions contained herein are the private views of the author and are not to be considered as official or as reflecting the views of the US Army, the Department of Defense, or the United States Government.

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Pathophysiology

The foot is the most common site of infection, and 70% of all mycetomas affect the foot. Other reported sites of involvement include the upper extremities, trunk, buttocks, eyelids, lacrimal glands, paranasal sinuses, mandible, scalp, neck, perineum, and testes. The disease is initially limited to the skin and subcutaneous tissue but may eventually spread through the fascial planes to contiguous structures such as muscle, bone, blood and lymphatic vessels, and nerves. Rarely, the disease may spread to the regional lymph nodes or viscera.

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Etiology

Agents that cause eumycetoma are primarily saprophytic microorganisms that are found in the soil and on plant matter. Healthy persons become inoculated with these agents as a result of the traumatic implantation of thorns, splinters, and other plant matter.

Pseudallescheria boydii is the most common etiologic agent of eumycetoma in the United States. Madurella mycetomatis accounts for most cases worldwide. Madurella grisea is a common etiologic agent in South America. Leptosphaeria senegalensis and Leptosphaeria tompkinsii are common causes of eumycetoma in West Africa. In general, the geographic distribution of the various mycetoma agents is related to the amount of rainfall and other climatic conditions. Each geographic region has a different list of most common agents.

Fungi with a white-to-yellow granule that cause eumycetoma include the following:

  • Acremonium species
  • Aspergillus nidulans
  • Aspergillus flavus
  • Cylindrocarpon cyanescens
  • Cylindrocarpon destructans
  • Fusarium species
  • Neotestudina rosatii
  • Polycytella hominis
  • P boydii

Fungi with a black granule that cause eumycetoma include the following:

  • Cladophialophora bantiana [3]
  • Corynespora cassicola
  • Curvularia species
  • Exophiala jeanselmei
  • L senegalensis
  • L tompkinsii
  • M grisea
  • M mycetomatis
  • Phialophora verrucosa [4]
  • Plenodomus auramii
  • Pyrenochaeta mackinnonii
  • Pyrenochaeta romeroi [5]
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Epidemiology

Frequency

United States

Sporadic cases have been reported in North America. In the United States, epidemiologic data from 1896-1964 include only 30 cases of eumycetoma, with the highest incidence in the Southwest. [6] Mycetoma is common in Mexico; in the United States, physicians in Texas and other border states are most likely to encounter patients with mycetoma.

International

Eumycetoma is mainly a disease of the tropical and subtropical zones especially between the Tropic of Cancer and the Tropic of Capricorn, that is, between the latitudes 15° S and 30° N. Eumycetoma is endemic in India, parts of Africa (eg, Sudan, [7] Senegal, Somalia, Nigeria, Zaire, Chad), Pakistan, Yemen, Mexico, Central America, South America (eg, Guatemala, Venezuela, Colombia, Brazil), and Indonesia.

Sex

The disease incidence is higher in males than females, with a ratio of 4-5:1.

Age

The disease incidence is highest in persons aged 10-40 years.

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Prognosis

Eumycetoma can be associated with significant morbidity in terms of gradual enlargement and deformity of the infected site. Severe involvement of the lower extremity may impair ambulation.

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