Fungal sinusitis: histologic spectrum and correlation with culture

Allergic fungal rhinosinusitis with skull base and orbital erosion

Introduction:

Allergic fungal rhinosinusitis is a benign, noninvasive sinus disease related to hypersensitivity to fungal infection having bony skull base and orbital erosion as common finding.

Patients and method:

This descriptive study was conducted at the department of otorhinolaryngology, Dow University of Health Sciences, Karachi, Pakistan, from April 2003 to March 2006. In forty-seven proven cases of allergic fungal sinusitis the following information was recorded: demographic data, signs and symptoms, laboratory investigation results, imaging results, pre- and post-operative medical treatment, surgery performed, follow up, and residual or recurrent disease. The Statistical Package for the Social Sciences version 10.0 software was used for data analysis.

Results:

Findings indicated that allergic fungal rhinosinusitis usually occurred in the second decade of life (51.06 per cent) in males (70.21 per cent), allergic rhinitis (100 per cent) and nasal polyposis (100 per cent). Nasal obstruction (100 per cent), nasal discharge (89.36 per cent), postnasal drip (89.36 per cent), and unilateral nasal and paranasal sinus involvement (59.57 per cent) were significant features. Aspergillus (59.57 per cent) was the most common aetiological agent. Combined orbital and skull base erosion was seen in 30.04 per cent of cases, with male preponderance 6.8:1. Endoscopic sinus surgery was performed in all cases, and recurrent or residual disease was observed in 19.14 per cent.

Conclusion:

Allergic fungal rhinosinusitis is a disease of young, immunocompetent individual. Skull base and orbital erosion are seen in one-third of cases. Bone erosion is 6.8 times more common in males than females. Orbital erosion is 1.5 times more common than skull base erosion. Endoscopic surgical debridement and drainage combined with topical steroids leads to resolution of disease in the majority of cases, without resorting to systemic antifungal agents, craniotomy or dural resection.

Spectrum of fungal rhinosinusitis; histopathologist's perspective

AIMS

Clinical presentation can provide a clue to the subcategories of fungal rhinosinusitis (FRS); however, tissue examination provides accurate classification. The aim was to analyse the incidence and histopathological spectrum of FRS.

METHODS AND RESULTS

A retrospective analysis of all the cases of rhinosinusitis reported in the last 5 years was carried out. Haematoxylin and eosin-stained sections along with special stains such as periodic acid-Schiff and Grocott's were examined. These cases were subclassified based on the presence of allergic mucin, mycelial elements and tissue reaction. Out of a total of 665 cases of rhinosinusitis, 284 (42.7%) were of FRS. On histopathological examination they were broadly categorized as: (i) non-invasive FRS (n = 171, 60.2%), which included 160 cases (56.3%) of allergic fungal rhinosinusitis (AFRS) and eleven (3.9%) of fungal ball; (ii) invasive FRS (n = 101, 35.6%), which included 48 cases (16.9%) of chronic invasive granulomatous FRS, four (1.4%) of chronic invasive FRS and 49 (17.3%) of acute fulminant FRS; and (iii) mixed pattern FRS, comprising 12 cases (4.25%).

CONCLUSIONS

AFRS is the most common type of FRS. Cases with mixed reaction pattern suggest that different types of FRS represent a progressive spectrum of disease. An exact histopathological categorization of FRS is important as regards treatment.

Fungus as the cause of chronic rhinosinusitis: the case remains unproven

PURPOSE OF REVIEW

To review the literature on the role of fungi in chronic rhinosinusitis (CRS) pathogenesis and the effect of antifungal drug therapy and antifungal immunotherapy.

RECENT FINDINGS

This paper reviews the most recent articles investigating the role of fungi in CRS pathogenesis. In addition to possible aberrant innate and adaptive antifungal immune responses and fungus antihost effects, which all may explain disease development, the effect of antifungal drug therapy and antifungal immunotherapy is reviewed.

SUMMARY

Although fungi can be detected in the nose and paranasal sinuses of nearly all patients with CRS and are present in almost all healthy controls, various studies suggest that there may be mechanisms by which fungi exert an effect on sinus mucosa in susceptible individuals only. Future studies will have to clarify the role of fungi in CRS, which fungal organisms, if at all, may be pathogenic and what exactly characterizes the immunological response to fungi that potentially results in the development of disease. Presently, in the absence of convincing immunological data and evidence for clinical improvement of CRS upon therapy with antifungal agents, the case against the fungus remains unproven.

The mold conundrum in chronic hyperplastic sinusitis

The role of fungi in chronic rhinosinusitis (CRS) is not clear. Fungi can be detected in the nose and paranasal sinuses of virtually all CRS patients; however, they also appear to be present in healthy controls. Various theories attempt to explain the mechanisms by which fungi can exert an effect on sinus mucosa in susceptible individuals. Further studies are necessary to clarify the role of fungi in CRS, which fungal organisms (if any) are pathogenic, and what exactly characterizes the immunologic response to fungi that may result in the development of disease. However, in the absence of convincing immunologic data and evidence of clinical improvement of CRS after antifungal therapy, the case against the fungus remains unproven.

Challenges and pitfalls of morphologic identification of fungal infections in histologic and cytologic specimens: a ten-year retrospective review at a single institution

Despite the advantages of providing an early presumptive diagnosis, fungal classification by histopathology can be difficult and may lead to diagnostic error. To assess the accuracy of histologic diagnosis of fungal infections vs culture ("gold standard"), we performed a 10-year retrospective review at our institution. Of the 47 of 338 positive mold and yeast cultures with concurrent surgical pathology evaluation without known history of a fungal infection, 37 (79%) were correctly identified based on morphologic features in histologic and/or cytologic specimens. The 10 discrepant diagnoses (21%) included misidentification of septate and nonseptate hyphal organisms and yeast forms. Errors resulted from morphologic mimics, use of inappropriate terminology, and incomplete knowledge in mycology. The accuracy did not correlate with preceding antifungal therapy (P = .14) or use of special stains (P = .34) and was not operator-dependent. Among 8 discrepancies with clinical follow-up available, 2 potential adverse clinical consequences resulted. While histopathologic identification of fungi in tissue sections and cytologic preparations is prone to error, implementation of a standardized reporting format should improve diagnostic accuracy and prevent adverse outcomes.

[Treatment of invasive rhinosinusitis--the case report]

The frequency of fungal etiology of sinusitis contains between 9 and 49 % according to different authors. Fungal rhinosinusitis has been divided into noninvasive and invasive forms. Noninvasive infections include fungus ball (mycetoma) and allergic fungal rhinosinusitis. Invasive infections include acute (or fulminates) fungal rhinosinusitis and invasive chronic rhinosinusitis. The case of chronic invasive rhinosinusitis was presented. Patient performed surgery--Functional Endoscopic Sinus Surgery and paranasal sinuses operation from subcranial approach. Surgery procedures were followed by antifungal pharmacotherapy (Orungal and Worykonazol). The presented case of fungal invasive chronic rhinosinusitis was treated according to recommended procedures with surgery followed by adequate antifungal farmacotherapy. In this case we have reached a successful outcome.

[Noninvasive fungal sinusitis (fungus ball)--diagnostic difficulties]

Noninvasive fungal sinusitis (fungus ball) is usually found in one sinus and the most frequently is caused by Aspergillus. Diagnostic criteria are based on histopathology, and fungal cultures are frequently negative. The clinical symptomatology mimics chronic rhinosinusitis and radiology, specially CT and MRI are helpful for making decision of surgery. The authors present 4 cases of fungus ball of the paranasal sinus. In one case clinical symptoms, endoscopic examination of nasal cavity and CT scans suggested foreign body in the maxillary sinus. In other case clinical and radiological evidences made us to thing of neoplasmatic disease of the frontal sinus. In remaining two cases mycetoma was found in the sphenoid sinus. Surgical removal was the treatment in all cases and followed by systemic antifungal therapy in one case because of bone destruction. Histopathology revealed hyphae of Aspergillus without evidence of tissue invasion, fungal cultures in two cases were negative, an in other two Aspergillus fumigatus culture were obtained.

Allergic fungal sinusitis: radiological and microbiological features of 59 cases

BACKGROUND AND OBJECTIVES

Allergic fungal sinusitis (AFS) is a relatively newly recognized entity consisting of a pansinusitis with allergic mucinous infiltrates in all involved sinuses. Historically mistaken for a paranasal sinus tumor, AFS is believed to be an allergic reaction to aerolized environmental fungi, usually of dematiaceous and Aspergillus species, in an immunocompetent host. We determined the occurrence of AFS in patients with chronic rhinosinusitis (CRS) to identify accurate preoperative parameters for AFS, as well as to identify the common fungi causing AFS in Saudi Arabia.

METHODS

We conducted a retrospective chart review of 406 cases of CRS undergoing functional endoscopic sinus surgery from 2001 to 2005. Data regarding patient demographics, presenting symptoms, ENT examination, laboratory and radiological features, histopathological features and fungal culture was collected and analyzed.

RESULTS

Fungal cultures were positive in 69 (16.9%) cases of CRS. Based on radiological features, histopathologic findings and culture results, AFS was diagnosed in 59 (14.5%) cases. Nasal polyposis was present in 56 (94.9%) cases; multiple sinuses were affected in all cases. Aspergillus species was the commonest causative fungal pathogen, being isolated in 40 (67.8%) cases, whereas dematiaceous fungi were isolated in 19 (32.2%) cases.

CONCLUSIONS

AFS has been an underdiagnosed clinical entity. Only increased awareness among physicians of fungal involvement will increase accuracy of diagnosis.

Negative impact of Aspergillus galactomannan and DNA detection in the diagnosis of fungal rhinosinusitis

A proportion of patients with chronic rhinosinusitis, especially if nasal polyps are present, have a diagnosis of fungal rhinosinusitis. The diagnosis is difficult to establish because the symptoms and clinical and radiological signs are non-specific. Also current diagnostic methods, i.e. histology, fungal staining and culture, are insensitive. The performance of the Aspergillus galactomannan (GM) ELISA and real-time PCR for Aspergillus fumigatus mitochondrial DNA was evaluated for the detection of Aspergillus in sinus mucus samples from 25 patients with chronic rhinosinusitis with nasal polyposis. The results were compared with those from nasal lavage fluid from 19 healthy volunteers. Seven patients (28 %) were diagnosed as having fungal rhinosinusitis according to the presence of filaments in histology or direct microscopy using Calcofluor white. All fungal rhinosinusitis patients were negative in the GM ELISA. GM ELISA was positive in five patients whose samples were negative using conventional methods and A. fumigatus PCR. Two out of seven patients with fungal rhinosinusitis were positive by A. fumigatus PCR: one also had a positive A. fumigatus culture, and one had hyphae consistent with Aspergillus in histology. One additional patient had a weak positive PCR result, but other fungal tests were negative. In control subjects, the GM ELISA was positive in 21 %, whereas direct microscopy, culture and A. fumigatus PCR were negative in all samples. Direct microscopy and culture together with histology remain pivotal in defining fungal rhinosinusitis diagnosis. A. fumigatus PCR may have additional value in allowing the diagnosis to be made sooner, whereas the GM ELISA is not reliable in diagnosing Aspergillus infection of the paranasal sinuses.

Usefulness of Fungiflora Y to detect fungus in a frozen section of allergic mucin

Allergic fungal sinusitis is a non-invasive disease characterized by pansinusitis with nasal polyps, with most causative agents being members of the dematiaceous fungi. Reported herein is the ninth Japanese case of allergic fungal sinusitis; an Alternaria species was culturally identified as the etiological agent. The present patient, a 32-year-old man, presented with multiple sinusitis and nasal polyps. Allergic mucin, which is a histological hallmark of this disease, was examined intraoperatively on frozen section. Although characteristic histology, including laminated masses of mucin and aggregates of eosinophils, was seen in HE-stained sections, fungal hyphae were scarce and recognized merely as clear spaces. Because fluorescent stilbene derivatives seem useful for the rapid detection of fungi, Fungiflora Y, a commercially available staining kit that includes a fluorescent stilbene derivative, was applied to the sections, and hyphae were successfully visualized using a fluorescence microscope. This stain takes only several minutes to perform. It is concluded that Fungiflora Y should be used when fungal elements are hard to find on HE stain, especially in cases in which rapid detection of fungus is requested.

The role of fungi in the airway of chronic rhinosinusitis patients

PURPOSE OF REVIEW

To analyze the role of fungi in the upper and lower airway in chronic rhinosinusitis patients.

RECENT FINDINGS

Recently, the involvement of the lower airway (as asthma, small airway disease and bronchial hyperresponsiveness) in chronic rhinosinusitis patients had been documented. Fungal spores after inhalation are submerged in the aqueous lining layers of the airway. The site depends on the size of the inhaled spores. The process of inhalation, retention and clearance of fungal spores may explain the positive culture results in both normal subjects and in most chronic rhinosinusitis patients. Fungal culture of different parts of the upper and lower airway in chronic rhinosinusitis patients had no correlation with cellular changes (local eosinophilia) and other clinical parameters. In chronic rhinosinusitis, with persistence of the chronic inflammatory process, the cells may be activated nonspecifically.

SUMMARY

The role played by fungi in most chronic rhinosinusitis patients as the target antigen of initiation of such chronic inflammation is still debated. With the presence of chronic eosinophilic inflammation in chronic rhinosinusitis, an exaggerated reaction to various inhaled antigens is anticipated. The role of fungi will be confirmed only when T cells within the sinuses are shown to be actively responding to fungal antigens cultured from the sinus and with the demonstration that their elimination will stop the disease.

Fungus balls of the paranasal sinuses: a review

In the past 30 years, thanks in part to the advance of both endoscopic technology and imaging possibilities, the classification, diagnosis, and management of rhinosinusitis caused by fungi have been better defined. These are basically divided into invasive and non-invasive forms based on the presence or absence of microscopic evidence of fungal hyphae within the tissues. Among the non-invasive fungal sinus diseases, fungus ball has been increasingly reported and large published series have allowed better characterization of the disease and the treatment strategies. Fungus ball of the paranasal sinuses is defined as the non-invasive accumulation of dense fungal concrements in sinusal cavities, most often the maxillary sinus. To describe this entity, confusing or misleading terms such as mycetoma, aspergilloma or aspergillosis would be best avoided. Clinical presentation is non-specific and the diagnosis is usually suspected on imaging studies. Surgical treatment, usually through an endonasal endoscopic approach, is curative. In this paper, we review the clinical, radiological, and pathological presentation of the fungus ball of the paranasal sinuses as well as the surgical management with emphasis on the transnasal endoscopic approach.

Paranasal fungal sinusitis: contributions of histopathology to diagnosis: a report of 60 cases and literature review

Sixty cases of fungal sinusitis are presented from 2 institutions, accumulated from 1971 to 2005. Fifty cases were from a large suburban general hospital and 10 from a major university referral center. Two of the 50 and 3 of the 10, respectively, were immunocompromised patients and had acute fulminant disease. This suggests that encountering the various forms of this disease may, in part, be dependent on the referral nature of the institution. The remainder were immune competent and had chronic symptoms of nasal discharge, stuffiness, and facial pain. Imaging studies frequently showed sinus expansion, opacification, and bone erosion, although no clinical or radiographic features were predictive of extrasinus extension. Chronic fungal sinusitis is principally represented by fungus ball/mycetoma and allergic fungal sinusitis. The recent literature suggests a predominance of or a predominant interest in allergic fungal sinusitis. Hyphal colonies and the presence of allergic mucin with scattered organisms are histologic observations and are the respective keys to these diagnoses. However, the etiologic role of the fungus in chronic cases is not settled. Patients with chronic sinusitis who yield positive sinus cultures only, but have no organisms visualized histologically, are not universally regarded as having fungal sinusitis. The interest in fungal sinusitis has generated a prominent role for the pathologist. An awareness of the various forms of the disease and thorough histopathologic study, including submission of all tissues removed at surgery and recognition of allergic mucin, are essential. Acute fulminant/invasive fungal sinusitis may require frozen section for adequate management.

The role of ubiquitous airborne fungi in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a confusing disease for both allergists and otorhinolaryngologists, partially due to its poorly understood pathophysiology and partially due to its limited treatment options. Several recent reports now provide evidence for a better understanding of the etiology and the relationship of CRS to airborne fungi, especially to Alternaria. First, the development of novel methods enables detection of certain fungi in mucus from the nasal and paranasal sinus cavities. Second, a non-immunoglobulin E-mediated immunologic mechanism for reactivity of CRS patients to certain common fungi has been described. Third, these fungi are surrounded by eosinophils in vivo, suggesting that they are targeted by eosinophils. Fourth, the preliminary results of studies using antifungal agents to treat patients with CRS are promising. Overall, these recent discoveries provide a logical mechanism for the pathophysiology of CRS, and they also suggest promising avenues for treatment of CRS with antifungal agents.

New paradigm for the roles of fungi and eosinophils in chronic rhinosinusitis

PURPOSE OF REVIEW

Chronic rhinosinusitis represents a challenge with its poorly understood pathophysiology and limited treatment options. Potential roles of fungi and eosinophils in the etiology and pathophysiology of chronic rhinosinusitis are summarized.

RECENT FINDINGS

Previously, the fungal role in chronic rhinosinusitis was limited to the rare subgroup, allergic fungal rhinosinusitis. Critical examination of earlier diagnostic criteria for allergic fungal rhinosinusitis reveals limitations. By using updated diagnostic standards and novel sensitive techniques to detect fungi, a higher number of patients can now be diagnosed with fungal rhinosinusitis. A novel non-IgE-mediated immunologic mechanism in chronic rhinosinusitis patients links the predominant eosinophilic inflammation to certain fungi. Overall, these new findings have implications for surgical and medical approaches, including anti-inflammatory and antifungal medications.

SUMMARY

Several classification schemes and diagnostic criteria describe chronic rhinosinusitis and make comparisons difficult. Preselection of patient groups within the chronic rhinosinusitis population and the lack of sensitive diagnostic techniques have prevented a full understanding of the syndrome complex of chronic rhinosinusitis. New results suggest a broader role for fungi in the pathophysiology of chronic rhinosinusitis, linking the eosinophilic inflammation to the presence of certain molds in the nasal and paranasal cavities. Although fungi are commonly found in nearly everyone, only chronic rhinosinusitis patients respond to them with an eosinophilic inflammation. These findings support a shift in the etiologic understanding of chronic rhinosinusitis away from a bacteriologic infectious pathogenesis to a fungal-driven inflammatory pathophysiology. Herein, the authors review earlier studies and describe an updated view on an old paradigm.

Does the triad of fungi, bacteria and exposure to moisture have an impact on chronic hyperplastic sinusitis?

Here we evaluated a possible relationship between chronic hyperplastic sinusitis (CHS) and moisture exposure and secondly a seasonal variation of fungal and bacterial findings in the healthy nose. In 28 CHS patients sinus mucus was collected during endoscopic sinus surgery. Samples from the nasal cavities of 19 healthy volunteers were collected by nasal lavage (NAL) in January and in September. Bacterial culture and fungal staining and culture were carried out. Histological samples from the sinus mucosa were obtained. Patients' medical history and environmental factors were enquired. Mold odor or moisture problems in the home or work environment were reported by 46% of the CHS patients. Patients who reported moisture exposure did not differ significantly from those who had not been exposed with regards to microbiological findings, tissue eosinophilia, and earlier operations. Cladosporium (16%) and Alternaria (11%) were found in NAL fluid collected in the autumn from the control subjects. No fungi were isolated from samples taken during the winter. An association between CHS or fungal sinusitis and moisture damage was not apparent in the present study. The fungal findings in the nasal cavity reflect the environmental exposure. This should be taken into account when NAL is used for microbiological studies.

PRACTICAL IMPLICATIONS

Living in a moldy house or working in a similar environment may increase the risk of respiratory symptoms and infections. However, our results suggest that chronic hyperplastic sinusitis and fungal sinusitis are not associated with moisture exposure. The nose is a good collector of particles in the air. Especially samples taken by the nasal lavage method reflect the environmental exposure. This should be taken into account when this method is used for microbiological studies.

Overview of fungal rhinosinusitis

The incidence of fungal rhinosinusitis has increased to such extent in recent years that fungal infection should be considered in all patients with chronic rhino sinusitis. In India though the disease was reported earlier only from northern regions of this country, nowadays the disease is increasingly diagnosed from other parts as well. The disease has been categorized with possible five types: acute necrothing (fulminant), chronic invasive, chronic granulomatous invasive, fungal hall (sinus mycetoma), allergic. The first three types are tissue-invasive and the last two are non-invasive fungal rhinosinusitis. However, the categorization is still controversial and open to discussion. Chronic fungal rhinosinusitis can occur in otherwise healthy host and Aspergillus flavus is the common etiological agent in Indian scenario. The pathophys iologic mechanism of the disease remains unclear. It may represent an allergic IgE response, a cell-mediated reaction, or a combination of two. Early diagnosis may prevent multiple surgical procedures and lead to effective treatment. Histopathology and radio-imaging techniques help to distinguish different types and delineate extension of disease process. Culture helps to identify the responsible etiological agent. The presence or absence oj precipitating antibody correlates well with disease progression or recovery. The most immediate need regarding management is to establish the respective roles of surgery and antifungal therapy. Non-invasive disease requires surgical debridement and sinus ventilation only, though, additional oral or local corticosterold therapy may be beneficial in allergie type. For invasive disease, the adjuvant medical therapy is recommended to prevent recurrence and further extension. Itraconazole has been found as an effective drug in such situation. Patients with acute neerotizing type require radical surgery and amphotericin B therapy.