Pulmonary, cardiac, and thyroid involvement in disseminated Pseudallescheria boydii

S. H. De Ment, R. R.L. Smith, J. E. Karp, W. G. Merz

Research output: Contribution to journalLetterpeer-review


The present case and the previous case descriptions of disseminated pseudallescheriasis are very similar in clinical presentation and organ involvement to disseminated aspergillosis. In addition, the hyphae of the two organisms are exceedingly difficult to differentiate in tissue sections, with the only distinguishable morphologic features being the presence of characteristic conidiophores and terminal conidia in P boydii. Most importantly, however, is the fact that, despite the numerous clinical and morphologic similarities of P boydii and Aspergillus, the two organisms respond quite differently to antifungal therapy. Pseudoallescheria boydii isolates are frequently resistant to amphotericin B in viro, with an MIC above attainable blood levels, and are susceptible to miconazole, as was the isolate obtained from this patient. Therefore, the empiric use of amphotericin B for clinical findings suggestive of invasive aspergillosis, as in this patient, may not afford an adequate therapeutic coverage. Rapid differentiation between Aspergillus species and P boydii can be difficult. Currently, culture of involved tissues is the only means for securing a specific diagnosis. This may require invasive procedures and several days of incubation time. An alternative solution may be the empiric combined use of amphotericin B and miconazole. However, the information concerning the combined effects of these two agents remains unclear as there is conflicting in vitro evidence that suggests both additive or synergic effects as well as antagonism.

Original languageEnglish (US)
Pages (from-to)859-861
Number of pages3
JournalArchives of Pathology and Laboratory Medicine
Issue number11
StatePublished - Dec 1 1984

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Medical Laboratory Technology


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