Acute Invasive Fungal Rhinosinusitis: Frozen Section Histomorphology and Diagnosis with PAS Stain

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.

Usefulness of intraoperative frozen section for diagnosing acute invasive fungal rhinosinusitis: A systematic review and meta‐analysis

“…The endoscopic findings can be variable such as erosive, edematous, dry, or pale mucosa initially, and change to ulceration, necrosis, or suspected ischemia when advanced. 10,11 Biopsy should be performed at any abnormal region such as pale or darkened mucosa, ulcer, or crusted area on endoscopic examination. However, when high suspicion and sufficient risk factors exist, biopsy at endoscopically normal tissues might be considered.…”

“…However, when high suspicion and sufficient risk factors exist, biopsy at endoscopically normal tissues might be considered. 11 The middle turbinate has been shown to be the most common site of fungal invasion (sensitivity of 75% to 86%, specificity of 100%). 14,15 Therefore, middle turbinate biopsy should…”

“…The following data were analyzed: diagnostic accuracy (i.e., diagnostic odds ratio [DOR]), summary receiver operating characteristic (SROC) curves, and areas under the curve (AUCs). [1][2][3][4][5]7,[9][10][11] DORs were calculated as (truepositives/false-positives)/(false-negatives/true-negatives) with 95% confidence intervals (CIs), using random-effects models that considered both within-study and betweenstudy variations. The DOR value ranges from zero to infinity, and higher values indicate better diagnostic performance.…”

Colonic mucormycosis in solid organ transplantation: Case report and review of the literature (colonic mucormycosis after DDLT)

“…Recently, it has been shown that frozen sections, especially with PAS staining, 14 are a sensitive test for rhinocerebral mucormycosis 15 . While this has not been studied in colonic mucormycosis, there exists a potential for earlier confirmation.…”

Evaluation of Fungal Sinusitis on Computed Tomography and Its Correlation With Endoscopy and Histopathology Findings

“…Acute invasive fungal rhinosinusitis (AIFRS) is a lethal form of sinusitis with high morbidity and mortality, in immunocompromised patients and it needs a rapid diagnosis and treatment. A rapid and accurate diagnosis is crucial for the timely and effective treatment and prevention of complications 9 .…”