Correspondence

Fungal Sinusitis

N Engl J Med 1997; 337:1633-1634November 27, 1997

Article

To the Editor:

In their otherwise excellent review of fungal sinusitis (July 24 issue),1 deShazo et al. have made two minor errors. First, in the text and in Table 1, they describe Pseudallescheria boydii as a dematiaceous (pigmented) mold, whereas in fact it is a hyaline (nonpigmented) mold.2 Second, the authors use the term “mycetoma” inappropriately as a synonym for fungus ball. Mycetoma refers strictly to invasive, tumefactive, and destructive infections of skin, soft tissue, and bone caused by a wide variety of aerobic actinomycetes and fungi that form compact mycelial aggregates, called grains or granules, within infected tissues.2 Although the mycelium in a fungus ball may superficially resemble that in a mycetoma granule, the distinction between the two is important. A fungus ball is a noninvasive, colonizing infection of a preformed air space that is usually cured by simple surgical removal and drainage. On the other hand, successful treatment of mycetoma, a truly invasive infection, frequently requires radical surgical débridement or amputation.

John C. Watts, M.D.
William Beaumont Hospital, Royal Oak, MI 48073

Francis W. Chandler, D.V.M., Ph.D.
Medical College of Georgia, Augusta, GA 30912

2 References

1. 1

   deShazo RD, Chapin K, Swain RE. Fungal sinusitis. N Engl J Med 1997;337:254-259
   Full Text | Web of Science | Medline

2. 2

   Chandler FW, Watts JC. Pathologic diagnosis of fungal infections. Chicago: ASCP Press, 1987.
   

To the Editor:

In their review of fungal sinusitis, deShazo et al. point out that fulminant invasive sinusitis can be caused by P. boydii. They state that when emergency surgery has yielded tissue confirming invasion, treatment should be given with amphotericin B, because azole antifungal agents lack activity against mucorales species. The authors imply that amphotericin B should be given alone, without azole antifungal agents. The problem is that azoles have activity against pseudallescheria but amphotericin B does not. Bennett states that the response of pseudallescheriasis to amphotericin B is minimal and that intravenous miconazole (800 mg every eight hours) is probably the regimen of choice for rapidly progressive infection.1

The pathologist must be able to differentiate pseudallescheria from aspergillus and mucorales. Differentiating pseudallescheria from mucorales is easy, because pseudallescheria has regular septate hyphae, which make it look very different from the irregular, ribbonlike, pauci-septate, wide-angle–branching mucorales. Differentiating pseudallescheria from aspergillus is much more difficult. Pseudallescheria has haphazard (random-angle) branching, midhyphal or terminal swellings, an absence of progressive (arboreal) branching, and the occasional presence of ovoid brown spores. Aspergillus sometimes has haphazard branching or hyphal swellings, and progressive branching is not always evident. The characteristic features of pseudallescheria can sometimes allow the pathologist to differentiate it from aspergillus. However, if the histologic features of the invading fungus are not specific enough to rule out pseudallescheria and if no culture result is available, perhaps the wisest treatment of acute, fulminant, invasive fungal sinusitis is a combination of amphotericin B and an azole.

Larry Nichols, M.D.
University of Pittsburgh Medical Center, Pittsburgh, PA 15213-2582

1 References

1. 1

   Bennett JE. Miscellaneous fungi, and prototheca. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas and Bennett's principles and practice of infectious diseases. 4th ed. Vol. 2. New York: Churchill Livingstone, 1995:2389-93.
   

Author/Editor Response

The authors reply:

To the Editor: Drs. Watts and Chandler raise two issues. First, the term “mycetoma” is strongly associated with the syndrome of maduromycosis, a chronic and slowly destructive infection of the cutaneous and subcutaneous tissues caused by a diverse group of fungi. In fungal syndromes other than maduromycosis, the distinction between mycetoma and a fungus ball has been blurred, and the terms have been used interchangeably. For that reason, it may be too late to restore the distinction. Thus, we have defined sinus mycetoma as noninvasive and have not distinguished between sinus mycetoma and fungus balls.1 When surgical material has dense accumulations of hyphae resembling mycetoma but the fungal elements invade tissue, blood vessels, and bone, a diagnosis of chronic invasive fungal sinusitis is made.2 Second, P. boydii often appears to be dematiaceous in culture, with hyaline hyphal elements in tissue. Most experts now classify the organism as a dematiaceous mold.3

Dr. Nichols points out that P. boydii can be mistaken for aspergillus, fusarium, and other fungi on microscopy.4 The identification of fungi on the basis of morphologic characteristics alone requires a high degree of expertise, and every attempt should be made to culture the fungus for precise identification. There are a number of reports suggesting that amphotericin B has limited efficacy against P. boydii and that azole antifungal agents can be lifesaving in such infections.5 Dr. Nichols's suggestion that a combination of amphotericin B and an azole be used to treat invasive fungal sinusitis and a fungus that is difficult to identify is a reasonable one. Nevertheless, until the results of controlled trials are available, the treatment of fungal infections will remain empirical.

Richard D. deShazo, M.D.
Kimberle Chapin, M.D.
Ronnie E. Swain, M.D.
University of South Alabama College of Medicine, Mobile, AL 36617

5 References

1. 1

   deShazo RD, O'Brien M, Chapin K, et al. Criteria for the diagnosis of sinus mycetoma. J Allergy Clin Immunol 1997;99:475-485
   CrossRef | Web of Science | Medline

2. 2

   deShazo RD, O'Brien M, Chapin C, Soto-Aguilar M, Gardner L, Swain R. A new classification and diagnostic criteria for invasive fungal sinusitis. Arch Otolaryngol (in press).
   

3. 3

   Larone DH. Medically important fungi: a guide to identification. 3rd ed. Washington, D.C.: ASM Press, 1995:132-3.
   

4. 4

   Schwartz DA. Pseudallescheriasis and scedosporiasis. In: Connor DH, Chandler FW, Schwartz DA, Manz JH, Lack EE. Pathology of infectious diseases. Norwalk, Conn.: Appleton & Lange, 1997:1074.
   

5. 5

   Walsh TJ, Hiemenz JW, Anaissie E. Recent progress and current problems in treatment of invasive fungal infections in neutropenic patients. Infect Dis Clin North Am 1996;10:365-400
   CrossRef | Web of Science | Medline