Main features of eumycotic and actinomycotic grainsa

Infections and speciesFindings by:
Fresh examinationHistology (H&E)
    Scedosporium apiospermum<2 mm, yellowish or white, soft, oval to lobed, “fig seed like”Compact, no cement, interwoven hyaline hyphae <5μm and swollen cells <20μm, eosinophilic border
    Acremonium kiliense<1.5 mm, white, soft, irregular shapeCompact, no cement, hyaline hyphae <4 μm, swollen cells <12 μm
    Aspergillus nidulans<2 mm, white, soft, oval to lobedCompact, no cement, interwoven hyaline hyphae <5 μm, eosinophilic border
    Neotestudina rosatiiWhite to brownish, soft, <1mm, fragmented angulated massCement and swollen cells at periphery embedded in cement and some central vesicles
    Madurella mycetomatis<2 mm, black, firm to brittle (coal consistency), oval to lobedCompact type, with brown-staining cement; vesicular type, with hyaline center and brown-staining cement and prominent <15 μm at edge
    Madurella grisea<1 mm, black, soft to firm, oval to lobedLittle brownish cement and polygonal cells at the periphery and central hyaline hyphae
    Exophiala jeanselmei<0.5 mm, black, soft, irregular to vermicularNo cement, hollow center, with melanin-pigmented vesicular cells <10 μm associated with short hyphae <4 μm
    Leptosphaeria senegalensis1 mm, black, soft, irregular shapeCement in outer zone, dark periphery with hyaline vesicular center
    Pyrenochaeta romeroi<2 mm, black, firm to brittle, oval to lobedBrownish cement at periphery, no vesicles
    Nocardia brasiliensis<0.5 mm, white, soft, irregularSmall, basophilic stained fringe in layers, homogenous loose clumps of bacterial filaments and rare clubs, positive Gram and Kinyoun stains
    Actinomadura madurae5 mm, yellowish to pink, oval to lobedAnamorphous empty center with a dense basophilic or pink border associated with loose fringe and clubs, gram positive
    Actinomadura pelletieri<1 mm, red, hard, oval to lobedHomogenous dark staining with light periphery and no clubs, easily fractured, gram positive
    Streptomyces somaliensis<2mm, yellow, hard, round to ovalAmorphous center amorphous center with basophilic layers associated with pink patches and dark bacterial filaments at the edge and no clubs, gram positive
  • a Adapted from reference 356 with permission from Elsevier.

  • b Other eumycetoma agents: Acremonium falciforme, Acremonium recifei, Aspergillus flavus, Leptosphaeria tompkinsii, Pyrenochaeta. mackinnonii, Curvularia geniculata, Curvularia lunata, Fusarium solani, Fusarium oxysporum, Exserohilum rostrata, etc.

  • cOther actinomycetoma agents: Nocardia asteroides, Nocardia caviae, Nocardia farcinica, Nocardia dassonvillei, etc.