ASPERGILLUS INFECTION OF SKIN

---

A selected case from the Clinicopathologic Skin Conference, Ochsner Foundation Hospital, New Orleans; 14 Dec. 1999. This case is furnished and presented by Richard J. Reed, M.D.

The organism identified on culture was said to be Aspergillus ustus.
Morphologically, the pleomorphism of the organism was similar to that seen in
the phaeohypomycotic abscesses. This organism however was not pigmented on
the H&E stained sections and a Fontana-Masson stain was not available.

It seems counterproductive to classify an organism with these pathogenetic
qualities in the category of aspergillosis. Classically, aspergillosis in the
immunocompromised is a severe, fulminating infection with poor tissue
response to the invasive organism and with vascular invasion a prominent
feature. Aspergillus may grow as a low-grade pathogen in cavities in the lung
and may be the pathogen in bronchocentric granulomatosis. The tissue phase of
classic aspergillus infection in the immunocompromised is a hyphal form of
uniform width and prominent branching at fairly acute angles. There is some
problem with the taxonomy of fungal organisms, if both the infection in this
patient and that in classic aspergillosis of the immunocompromised qualify as
aspergillosis. It would appear there is risk of failing to communicate if both
conditions can be dismissed as aspergillosis.
 

 
 
 

I

Fig. 1 In the upper portion of the reticular dermis, there is an irregular defect. The palisaded cells outlining the defect are activated histiocytes

 

Fig. 2 At higher magnification the zone of palisaded histiocytes forms a relatively pure infiltrate with a paucity of other cell types. The adjacent dermis is not significantly involved by infiltrates of lymphocytes, plasma cells, or neutrophils. The green arrows point to linear structures with represent fungal organisms.

 

Fig. 3 With this PAS stain, the organisms in this field (arrows) form pseudohyphae.

 

Fig. 4 Numerous organisms are represented. Some near the margin of the defect are poorly stained and probably are dead. Some form pseudohyphae and along the pseudohyphae there are bulbous expansions. One bulbous expansion is below the center of the field (arrow). PAS stain.

 

Fig. 5 Bulbous expansions of branching septate hyphae are represented. Some hyphae show branching at a wide angle. There is pleomorphism.

 

Fig. 6 The pleomorphic quality of the fungal organism is a prominent feature.

Click on your browser's 'Back' button to return to the previous page.