Mycetoma Clinical Presentation

Updated: Apr 07, 2021
  • Author: Lucio Vera-Cabrera, PhD; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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Mycetoma occurs most commonly in people who work in rural areas where they are exposed to acacia trees or cactus thorns containing the etiologic agents that normally live as saprobes. However, the disease has also been found in individuals who work in the city in various occupations.

The classic clinical triad of mycetoma is tumor or soft-tissue swelling, sinus tracts, and characteristic macroscopic grains. The grains typically represent aggregates of the infecting organisms. The earliest sign is often painless subcutaneous swelling. Some patients may give a history of a penetrating injury at the site of involvement.

Several years later, a painless subcutaneous nodule is observed. After some years, massive swelling of the area occurs, with induration, skin rupture, and sinus tract formation.

As the infection spreads to contiguous body parts, old sinuses close and new ones open.

Nearly 20% of patients with mycetoma experience associated pain, usually due to secondary bacterial infection or, less commonly, bone invasion.

Constitutional symptoms and signs of mycetoma are rare.

Patients may report a deep itching sensation.


Physical Examination

Irrespective of the causal agent, the appearance of the mycetoma lesion is consistent. Initially, subcutaneous swelling is present. In a later phase, a subcutaneous nodule develops. Eventually, massive swelling with induration, rupture of the skin, and formation of sinus tracts occur.

The skin is usually darker and firmer than the surrounding areas. Nodules, abscesses, and fistulae draining a clear viscous or purulent exudate can be observed. Granules of the microorganisms may occasionally be seen with the naked eye, as in the case of mycetoma caused by A madurae and M mycetomatis, among others.

In general, eumycetoma is more circumscribed and progresses slower than actinomycetoma.

The most common anatomical locations affected by this disease are the arms and legs, particularly the feet and legs. In Mexico, the next most commonly affected site is the thoracic area, but this varies from country to country. Rarely, mycetoma can also be observed on the buttocks, groin, head, and neck.

 See the images below.

Actinomycetoma of the foot (left) and arm (center) Actinomycetoma of the foot (left) and arm (center) caused by Nocardia brasiliensis. Multiple nodules and fistulae are present. Microscopic examination of the pus (right). Granules are observed, which are multilobulated and surrounded by abundant clubs.
Eumycetoma. Mycetoma of the hand (left). Microscop Eumycetoma. Mycetoma of the hand (left). Microscopic features of a Madurella mycetomatis grain are observed (center). Notice the presence of brownish hyphae and intercellular cement (hematoxylin and eosin stain). Macrocolony of another eumycotic agent, Scedosporium apiospermum (Pseudallescheria boydii) (right).

Regional lymphadenopathy is unusual. Lymphatic spread of mycetoma to regional nodes occurs in only 1-3% of affected patients. Secondary bacterial infection or a local immunologic reaction may enlarge the regional lymph nodes. Lymphatic obstruction and fibrosis can cause lymphedema and erythema.

Pulmonary mycetoma has been found to develop and progress more rapidly in individuals infected with HIV.