• Humans
• Sinusitis/diagnosis
• Sinusitis/therapy
• Sinusitis/microbiology
• Rhinitis/therapy
• Rhinitis/microbiology
• Rhinitis/diagnosis
• Invasive Fungal Infections/diagnosis
• Prognosis
• Antifungal Agents/therapeutic use
• Risk Factors
• Immunocompromised Host
• COVID-19/epidemiology
• COVID-19/complications
• Rhinosinusitis

• Humans
• COVID-19/complications
• Algorithms
• Sinusitis/microbiology
• Sinusitis/diagnosis
• Sinusitis/diagnostic imaging
• SARS-CoV-2
• Tomography, X-Ray Computed/methods
• Invasive Fungal Infections/diagnosis
• Invasive Fungal Infections/diagnostic imaging
• Invasive Fungal Infections/microbiology
• Eye Infections, Fungal/diagnosis
• Eye Infections, Fungal/microbiology

• MRI
• coagulative necrosis
• diffusion restriction
• fungal load
• lack of contrast enhancement

Rhinocerebral mucormycosis has emerged as a common coinfection in coronavirus disease 2019 (COVID-19) patients during the convalescence period. Frequent spread of disease from sinonasal mucosa to bone, neck spaces, orbit, and brain occurs along the perivascular/perineural routes or through direct invasion. Brain involvement represents severe manifestation and is often associated with poor functional outcomes and high mortality rates. Magnetic resonance imaging (MRI) is the modality of choice for the intracranial assessment of disease severity in mucormycosis. Early and accurate identification of intracranial extension is imperative to improve survival rates. With this pictorial essay, we aim to familiarize the readers with the cross-sectional imaging features of intracranial complications of mucormycosis. The radiological details in this essay should serve as a broad checklist for radiologists and clinicians while dealing with this fulminant infection.

• Acute invasive fungal rhinosinusitis
• Magnetic resonance imaging
• Mortality
• Prognostic findings
• Visual acuity

• Humans
• Rhinitis/diagnostic imaging
• Rhinitis/microbiology
• Prognosis
• Retrospective Studies
• Mycoses/diagnosis
• Sinusitis/diagnostic imaging
• Sinusitis/microbiology
• Magnetic Resonance Imaging/methods
• Acute Disease

The objective is to describe the radiological imaging findings of post-COVID-19 acute invasive fungal rhinosinusitis (AIFRS), being familiar with the wide variety of imaging spectrum, thus raising the suspicion for early diagnosis. Methods: In this retrospective study, we reviewed the imaging findings in 54 patients with proven post-COVID-19 AIFRS who underwent endoscopic/surgical debridement from April 2020 to September 2021. Most of these patients presented with facial or orbital swelling or facial pain. Medical records with a special emphasis on radiological imaging (50 NCCT of the paranasal sinuses and 17 MRIs of the orbit) were reviewed regarding the degree of mucosal disease of sinuses, nasal cavity, and nasopharynx, extra sinus soft tissue infiltration, especially orbital and cerebral extension (parenchymal, cavernous sinus, vascular or neuro-invasion).

We reported findings in 54 patients with post-COVID-19 AIFRS, of whom 30 were men and 24 were women with a mean age of 48.06. Unexpectedly, infiltration of pterygopalatine fossa was found to precede mucosal opacification of sinuses nasal cavity and affection of nasopharynx. Out of 54 patients, 49 showed inflammatory changes involving pterygopalatine fossa, 29.6% of patients showed infiltration of orbital tissues, 22 patients suffered from a fungal invasion of the cavernous sinus and 3 patients had carotid artery involvement.

Imaging findings of AIFRS significantly vary from subtle mucosal thickening of paranasal sinuses, up to orbital and intracranial extension with vascular thrombosis and neuroinvasion. The hallmark inflammatory tissue infiltration into the pterygopalatine fossa and facial soft tissue may precede mucosal disease.

• covid-19, coronavirus disease 2019
• ca-rocm, coronavirus disease 2019 associated rhino-orbital-cerebral mucormycosis
• sars-cov-2, severe acute respiratory syndrome coronavirus 2
• co-rads, covid-19 reporting and data system
• hba1c, glycated haemoglobin
• fiesta-c, fast imaging employing steady-state acquisition
• ctsi, ct severity score
• enti, extra-nasal tissue infarction

Trismus is a common problem with various causes. Any abnormal conditions of relevant anatomic structures that disturb the free movement of the jaw might provoke trismus. Trismus has a detrimental effect on the quality of life. The outcome of this abnormality is critically dependent on timely diagnosis and treatment, and it is difficult to identify the true origin in some cases. We present a rare case of trismus due to fungal myositis in the pterygoid muscle, excluding any other possible pathogenesis.

The patient presented with a 2-mo history of restricted mouth opening. Computed tomography showed obvious enlargement of the left pterygoid muscles. Furthermore, the patient had trismus without obvious predisposing causes. The primary diagnosis was pterygoid myosarcoma. Consequently, lesionectomy of the left pterygoid muscle was performed. Intraoperative frozen biopsy implied the possibility of an uncommon infection. Postoperative pathologic examination confirmed myositis and necrosis in the pterygoid muscle. Fungi were detected in both muscle tissue and surrounding necrotic tissue. The patient recovered well with antifungal therapy and mouth opening exercises. The rarity of fungal myositis may be responsible for the misdiagnosis. Although the origin of pathogenic fungi is still unknown, we believe that both hematogenous spread and local invasion could be the most likely sources. To the best of our knowledge, this is the first case in the literature that reported fungal myositis in pterygoid muscles as the only reason that results in trismus.

Surgeons should remain vigilant to the possibility of trismus originating from fungal myositis.

• Trismus
• Fungal myositis
• Infection
• Immunodeficiency
• Pterygoid muscle
• Case report

A subset of diabetic COVID-19 patients treated with steroids, oxygen, and/or prolonged intensive care admission develop rhino-orbito-cerebral mucormycosis. Radiologists must have a high index of suspicion for early diagnosis, which prompts immediate institution of antifungal therapy that limits morbidity and mortality. Assessment of disease extent by imaging is crucial for planning surgical debridement. Complete debridement of necrotic tissue improves survival. Imaging features reflect the angioinvasive behaviour of fungal hyphae from the Mucoraceae family, which cause necrotising vasculitis and thrombosis resulting in extensive tissue infarction. Contrast-enhanced magnetic resonance imaging (MRI) is the imaging technique of choice. The classic “black turbinate” on contrast-enhanced imaging represents localised invasive fungal rhinosinusitis (IFRS). A striking radiological feature of disseminated craniofacial disease is non-enhancing devitalised and necrotic soft tissue at the orbits and central skull base. Sinonasal and extrasinonasal non-enhancing lesions in IFRS are secondary to coagulative necrosis induced by fungal elements. Multicompartmental and extrasinonasal tissue infarction is possible without overt bone involvement and caused by the propensity of fungal elements to disseminate from the nasal cavity via perineural and perivascular routes. Fungal vasculitis can result in internal carotid artery occlusion and cerebral infarction. Remnant non-enhancing lesions after surgical debridement portend a poor prognosis. Assessment for the non-enhancing MRI lesion is crucial, as it is a sole independent prognostic factor for IFRS-specific mortality. In this review, we describe common and uncommon imaging presentations of biopsy-proven rhino-orbito-cerebral mucormycosis in a cohort of nearly 40 COVID-19 patients.

• Invasive fungal infections
• Magnetic resonance imaging
• Nasal cavity
• Paranasal sinuses
• Squamous cell carcinomas

Acute invasive fungal rhinosinusitis (AIFRS) can spread beyond the sinonasal cavity. It is necessary to analyze the association between the specific site involved in the extrasinonasal area and the survival rate to predict patient prognosis. We investigated 50 patients who had extrasinonasal lesions on preoperative gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) scan and underwent wide surgical resection of AIFRS. The specific sites with loss of contrast enhancement (LoCE) on Gd-enhanced MRI were analyzed for AIFRS-specific survival rate. The most common underlying disease was diabetes mellitus followed by hematological malignancy. The most common symptoms were headache and facial pain. Seven patients (14.0%) expired because of AIFRS progression. Poor prognosis was independently associated with LoCE at the skull base on preoperative MRI (HR = 35.846, P = 0.004). In patients with AIFRS extending to the extrasinonasal area, LoCE at the skull base was an independent poor prognostic factor.

Fungal rhinosinusitis (FRS) is commonly caused by various Aspergillus species (spp) and Mucorales fungi, and the treatment and prognosis of cases differ depending on the causative fungus. The present study describes a novel immunohistochemical method that has high sensitivity and specificity for distinguishing between these two types of fungi in patients with FRS. Three groups were included in the study. Group A included formalin-fixed paraffin-embedded blocks of 51 nasal tissue specimens of patients with FRS (27 Aspergillus spp and 24 Mucorales) that were continuously obtained from the Department of Pathology of Tongren Hospital in Beijing as the experimental group and 34 cultures (26 Aspergillus spp and 8 Mucorales) of FRS that were randomly selected from the bacterial laboratory of Tongren Hospital in Beijing to verify the staining results of the paraffin-embedded blocks. Formalin-fixed paraffin-embedded blocks of 10 esophageal cancer specimens were included in Group B as the positive control group. All specimens in Groups A and B were stained with interferon-γ (IFN-γ) antibody. Group C consisted of the same specimens as described in Group A, however, when performing the immunohistochemical assay, IFN-γ antibody was replaced by PBS and this served as the negative control group. The differences in IFN-γ immunohistochemical staining between Aspergillus spp and Mucorales were analyzed. Staining of IFN-γ in paraffin-embedded samples was positive in 92.6% (25/27) of specimens in which Aspergillus spp were the causative pathogen, which was significantly higher compared with specimens in which Mucorales was causative (P<0.001), with only 4.2% (1/24) of specimens staining positive for IFN-γ. Immunohistochemical staining of cell cultures was 100% positive for Aspergillus spp, whereas all Mucorales were negative. Thus, the results of the current study indicated that IFN-γ antibody immunohistochemical staining may be used as a novel diagnostic tool to distinguish between Aspergillus spp and Mucorales when identifying the causative agent in FRS, providing a useful supplementary test to the current immunohistochemical methods in the clinical diagnosis of FRS.

• interferon-γ
• fungal rhinosinusitis
• Aspergillus
• Mucorales
• sensitivity
• specificity

• Bacteria
• Fungi
• High-throughput sequencing
• Maxillary sinusitis

Acute invasive fungal rhinosinusitis is a lethal infectious process afflicting immunocompromised individuals. Knowledge about this disease is still limited due to the scarcity of animal models designed to study the pathogenesis of this infection. Mast cells are tissue-resident immune cells that participate in a variety of allergic and inflammatory conditions. Limited attention has been given to the role of mast cells in acute invasive fungal rhinosinusitis. Therefore, the objectives of this study were to create a rat model of acute invasive fungal rhinosinusitis based on analyzing the impact of different fungal concentrations on establishing infection, and to observe the changes of mast cells in rats with this disease.

Sprague–Dawley rats were divided randomly into four groups, three of which were experimental and received different concentrations of Aspergillus fumigatus inoculations, and one was a control group (D). The inoculated Aspergillus fumigatus concentrations were 5 × 10⁷ conidia/ml in group A, 10⁷ conidia/ml in group B, and 10⁶ conidia/ml in group C. Before fungal inoculation, rats were immunosuppressed using cyclophosphamide and cortisone acetate, and had Merocel sponges inserted into the right nares. Hematology and histopathology investigations were then performed.

An acute invasive fungal rhinosinusitis rat model was established successfully with an incidence rate of 90% in group A, 50% in group B and 10% in group C. Aspergillus fumigatus invasion was observed in 20% of the lungs in group A, but was not seen in the remaining groups. In addition, no fungi invaded the orbital tissue, brains, livers, spleens or kidneys of any rat. Compared with the control set, the total number of mast cells in the experimental groups was not significantly increased, but mast cell degranulation, on the other hand, was only found in infected nasal cavities.

This investigation illustrates that various fungal concentrations have different effects on the incidence of acute invasive fungal rhinosinusitis, and it also demonstrates the feasibility of using this model to study the process of fungal rhinosinusoidal invasion. In addition, the results suggest that mast cells may play a role in the protection of sinuses against acute Aspergillus fumigatus infection and in the clearance of established hyphal masses.

The online version of this article (doi:10.1186/s12879-014-0713-y) contains supplementary material, which is available to authorized users.