Page 195 - Concise Pathology for Exam Preparation ( PDFDrive )

180 SECTION I General Pathology

Mycetoma
Mycetoma can be classified as a Eumycetoma—a fungal disease, or Actinomycetoma—an
old name for Actinomycosis.
Eumycetoma
• It is a chronic, specific, granulomatous, fungal disease which mainly affects the foot.
Mycetoma pedis is also known as Madura foot (7.13a). This infection is endemic in
Africa, India and Central and South America and is usually acquired while performing
agricultural work due to contact with grains of fungal spores that have been discharged
onto soil.
• Infection usually manifests as an open area or break in the skin. It is clinically character-
ized by draining sinuses, granules and tumefaction.
• The disease usually involves cutaneous and subcutaneous tissue, and may also spread
to underlying fascia and bone. Sinuses discharge serosanguinous fluid containing gran-
ules that vary in size, colour and degree of hardness, depending on aetiologic species,
and are hallmark of mycetoma (Fig. 7.13).
• Eumycetoma may be of several varieties, depending on colour of granulous
discharge:
• Red—Actinomadura pelletieri
• White or yellow—Acremonium species, Aspergillus nidulans, Pseudallescheria boydii
• Black—Curvularia lunata, Exophiala jeanselmei, Madurella grisea, Madurella myceto-
matis
Actinomycetoma
• Actinomycosis is a rare, chronic and slowly progressive granulomatous disease caused
by filamentous, Gram-positive, anaerobic bacteria from the Actinomycetaceae family
(genus Actinomyces) such as Actinomyces israelii or A. gerencseriae. It can also be caused
by Propionibacterium propionicus.
• Actinomyces are commensals of the human oropharynx, gastrointestinal tract and uro-
genital tract. When tissue integrity is breached through a mucosal lesion they can invade
local structures and organs and become pathogenic.
• The condition tends to affect certain areas of the body and can be classified into four
main types:
• Oral cervicofacial actinomycosis
• Thoracic actinomycosis
• Abdominal actinomycosis
• Pelvic actinomycosis

Multiple sinuses

FIGURE 7.13. Mycetoma foot showing numerous draining sinuses.

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