Recurrent pituitary adenoma was identified and showed the same microscopic features (high cellularity and necrosis) when compared to the original tumor resection specimen. The MIB-1 proliferation index for the tumor was 16.3% (128 positive/783 cells).
Unsuspected fungal elements with basophilic staining on HE, thick-walled hyphae with swollen segments, septae, pigment production (confirmed by a Fontana-Masson stain) and yeast forms were also seen. Classic ascomata) formation containing nucleated conidiospores) were easily identified. No inflammatory response or other evidence of invasive infection were seen although the recurrent adenoma abutted fungal growth.