clearly outlined the fungi having septate hyphae and Masson-Fontana showed blackish pigments suggestive of phaeohyphomycosis (Figure 5).
An ultrasound (US)-guided percutaneous biopsy of the mass revealed a chronic organizing abscess with filamentous bacteria on GMS stain
consistent with an actinomycosis abscess.
Histopathological evaluation of epidural tissue showed predominantly chronic and granulomatous inflammation with numerous large broad based budding organisms seen in black on GMS stain
Budding yeast were seen on Gormori methenamine silver (GMS stain) (Figure 2).
BAL revealed filamentous fungi on direct GMS stain, and no microorganisms on acid fast stains.
Histoplasma capsulatum can be identified on GMS stain
of a variety of tissues, including bone marrow, lymph node, skin lesion biopsy, liver biopsy, and transbronchial lung biopsy specimens.[14,17] Liver biopsy may prove particularly fruitful in those patients with elevations of serum liver enzymes.
Do the black particles on the GMS stain represent fungi?
Although some laboratories additionally perform a periodic acid-Schiff stain for fungi, the GMS stain is preferable, primarily because periodic acid-Schiff provides less contrast between fungi and background debris.
Caption: Figure 4: GMS stain
highlighting delicate branched filaments.
PAS and GMS stains
must be used to properly visualize the hyphae .
Proximal pancreas was negative for microorganisms on AFB and GMS stains
but showed nonnecrotizing granulomas compatible with patient's history of sarcoidosis (Figure 3).
In comparison to the results obtained with MMPS, GMS stained
cellulose fibers gray to black whereas Congo red imparted an orange color to MCC.