Abstract
Acute invasive fungal rhinosinusitis (AIFRS) is a fulminant infection in immunocompromised patients requiring rapid diagnosis (DX), frequently made on frozen section (FS) of sinonasal biopsies, followed by prompt surgical debridement. However, FS interpretation is often difficult and DX sometimes not possible. In this study we sought to characterize reasons for misinterpretation and methods to improve diagnostic accuracy. The FS slides from 271 biopsies of suspected AIFRS in a 16-year period were reviewed and the morphologic features evaluated for their utility in DX. Recurring specific patterns of necrosis were identified, which to our knowledge have not been described in the literature. Although they provide strong evidence for AIFRS, identifying fungus consistently in necrotic tissue is essential for DX. Clues to identifying fungus and pitfalls in misidentification were identified, but even with expert knowledge of these, a gap in accurate DX remained. The key to FS DX of AIFRS is to improve fungus identification in necrotic tissues. Methods had been sought in the past to stain fungus at FS without consistent success. The Periodic Acid Schiff’s Reaction for Fungi was modified by our histopathology department for use on frozen tissue (PASF-fs) resulting in effective staining of the fungus. It stained fungus on all 62 positive slides when applied retrospectively over hematoxylin and eosin (H&E) stained FSs and used prospectively at FS for DX. Although knowledge of histologic morphology on FS is important, the crucial value of this study is the novel use of PASF-fs to identify fungus in the DX of AIFRS.
Highlights
Acute invasive fungal rhinosinusitis (AIFRS) is typically a fulminant infection with high morbidity and mortality [1, 2] in immunocompromised patients [3]
Histopathologic analysis by frozen section (FS) has become a preferred diagnostic method owing to its rapid turnaround in the DX of AIFRS [8,9,10,11] but its accuracy is diminished by difficulties in recognizing the disease
Processed hematoxylin and eosin (H&E) and Gomori’s methenamine silver (GMS) stained slides were reviewed for accuracy of the final FS DX with the final pathologic DX which was treated as the true DX
Summary
Acute invasive fungal rhinosinusitis (AIFRS) is typically a fulminant infection with high morbidity and mortality [1, 2] in immunocompromised patients [3]. Histopathologic analysis by frozen section (FS) has become a preferred diagnostic method owing to its rapid turnaround in the DX of AIFRS [8,9,10,11] but its accuracy is diminished by difficulties in recognizing the disease. We theorize this may be in part because a detailed histomorphologic description of this disease process as seen on FS has not been documented in the literature. We present a description of the important diagnostic features of AIFRS with emphasis on problems in interpretation at FS and potential solutions
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