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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4416_Библиотеки_им_академика_М_И_Перельмана
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Section 2 Inammatory Nasal Conditions102
BA
Figs. 7.3A and B: Allergic fungal sinusitis. (A) Sinus window: expansion of bilateral
maxillary, ethmoid sinuses; central hyperdensity, peripheral hypodensity (white arrow),
remodeling and thinning of walls (black arrow); and (B) Bone window. Erosion of lamina
papyracea, intraorbital exten sion (arrowhead).
A
C
B
Figs. 7.4A to C: Allergic fungal sinusitis:
underestimation of disease on MRI. (A)
Central hyperdense contents lling left
maxillary and ethmoid sinuses (arrow). Erosion
of lamina papyracea and intraorbital extension
(arrowhead); (B) Low signal intensity on T2WI
in maxillary and ethmoid sinuses (arrow)
mimics normal aerated sinuses; and (C)
Enhancing mucosal lining and extrasinus soft
tissue (arrow).
Fungal Ball/Mycetoma
■ Synonym: Aspergilloma
■ A mass like noninvasive lesion composed of fungal hyphae forms within
the sinus.
BA
Figs. 7.5A and B: Mycetoma: NCCT. (A) Soft tissue opacication of left maxillary sinus and
nasal cavity (asterisk); and (B) Mild thickening and sclerosis of bony walls (arrow).
■ It is seen in immunocompetent patients, not atopic, more common in
women, and older age.
■ Mostly single sinus is involved and maxillary sinus is most commonly
aected. Less frequently sphenoid, frontal and ethmoid sinuses are
involved in that order.4
■ Organism: Aspergillus fumigatus is most frequently responsible.
■ Histopathology: Fungal hyphae are seen with no background of allergic
mucin (versus AFS), deposits of calcium oxalate may be present.
■ NCCT (Figs. 7.5A and B):
• Soft tissue opacication of involved sinuses
• Central hyperdensities with or without calcications
• Pattern of calcication is ne, round or linear
• Peripheral, hypodense inamed mucosa may be seen
• Sinus cavity volume is normal or decreased; expansion with thin walls
is far less frequent
• Bony walls show thickening and sclerosis.
■ MRI (Figs. 7.6A and B):
103Chapter 7 Imaging in Fungal Sinusitis
BA
Figs. 7.6A and B: Mycetoma: MRI (same patient as in Figs. 7.5A and B). (A) Mass like
heterogenous lesion with central T2 hypointensity (asterisk); and (B) Non-enhancing mass
with only mucosal enhancement (arrow).
Section 2 Inammatory Nasal Conditions104
BA
Figs. 7.7A and B: Acute invasive fungal sinusitis (mucormycosis). (A) Bilateral maxillary
sinusitis. Left premaxillary soft tissue with intact bony margins (arrow); (B) Necrosis in the
extrasinus soft tissues (asterisk).
• T1: Heterogenous, predominantly low signal intensity
• T2: Also low signal intensity (due to calcium, magnesium and
manganese salts)
• CEMRI: Mild/no enhancement of the sinus contents.
■ Differential diagnosis:
• Chronic obstructed sinus (non-fungal) with inspissated secretions:
cannot be dierentiated on imaging.
Invasive Fungal Sinusitis
Acute Invasive
■ Synonym: Rhino-sino-orbito-cerebral mycosis
■ Acute onset, rapidly progressive fungal infection with invasion of the
vessels and surrounding soft tissues.5
■ Mostly immunocompromised patients, occasionally in immunocompetent.
■ Acute clinical illness, rapidly progressive with high mortality.
■ Fungi responsible:
• Aspergillus sp. (more frequent in neutropenic patients)
• Mucoraceae family (Mucor, Rhizopus, and Absidia) more common in
diabetics especially poorly controlled ones.
■ Symptoms: Nonspecic, fever, rhinorrhea, facial pain, headache, and
diplopia.
■ Frequent sites: Maxillary and ethmoid sinuses.2
■ CT
• Mucosal thickening/opacication of aected sinuses
• Hyperdense areas within
• Adjoining soft tissue thickening may be seen despite intact bony sinus
walls (Figs. 7.7A and B).
105Chapter 7 Imaging in Fungal Sinusitis
A
Figs. 7.8A and B: Acute invasive fungal sinusitis with bone erosions. (A) Mucosal
thickening left maxillary sinus. Erosion of sinus walls with premaxillary (asterisk) and
retroantral (arrow) soft tissue; and (B) Permeative lysis of sphenoid bone (arrow) with
extrasinus soft tissue in infratemporal fossa.
A
Figs. 7.9A and B: Acute invasive fungal sinusitis magnetic resonance imaging (MRI).
(A) Intermediate to hypointense signal intensity soft tissue in right orbit (arrow), orbital apex
and cavernous sinus (arrowhead); and (B) Abnormal mucosal enhancement in ethmoid
sinuses, right orbit, dura along temporal fossa (black arrow) and cavernous sinus (asterisk).
B
B
• is extrasinus spread is thought to occur through microvascular
channels in the bone. e presence of soft tissue edema/inltration is
a poor prognostic indicator.
• Sites of extrasinus spread include: premaxillary tissues, retroantral fat
as well as pterygopalatine fossa.
• Bony erosions are seen in the more severe forms (Figs. 7.8A and B).
■ MRI
• Opacied sinuses may appear hypointense on both T1 and T2
weighted images (T2WIs).
• As stated earlier, MRI can underestimate the extent of involvement
and should always be correlated with the CT.
• CEMRI is superior to CT for demonstrating the soft tissue, intracranial
and intraorbital extension (Figs. 7.9A and B).
• Soft tissue edema: T1WI shows replacement of fat in aected areas
with soft tissue, hyperintense on T2WI with contrast enhancement.
Section 2 Inammatory Nasal Conditions106
BA
Figs. 7.10A and B: Complicated fungal sinusitis. (A) Rim enhancing abscess right
temporal lobe (arrow) and abnormal enhancing soft tissue in the temporalis muscle and
infratemporal fossa (asterisk). Thrombosis of right cavernous internal carotid artery (ICA)
(arrowhead); and (B) Diffusion-weighted imaging (DWI) image showing multiple infarcts right
middle cerebral artery (MCA) and watershed territory.
• Characteristic sign: “Black turbinate sign”—refers to absence of
enhancement in areas, which normally enhance such as nasal mucosa
and the turbinates. Lack of enhancement implies tissue necrosis and
is highly suggestive of angioinvasive fungal sinusitis.2
• Critical areas of extension to be mapped: orbit, intracranial extension
including cavernous sinus.
• Involvement of the internal carotid artery in its cavernous part in the
form of thrombosis, mycotic pseudoaneurysm formation or even
dissection should be looked for (Figs. 7.10A and B).
■ Aspergillosis versus Mucormycosis: It is dicult to dierentiate
aspergillosis from mucormycosis and biopsy is essential. Some
characteristic features described for mucormycosis include:
• e earliest signs described by Green et al.6 were nodular mucosal
thickening, with no air-uid levels and patchy erosion of the bony sinus
walls. ese signs however are not pathognomonic for mucormycosis.
• Characteristic distribution of mucormycosis is the involvement of
nasal cavity, sinuses, and orbit.
• Periosteitis and osteitis are typically present along with low density
areas within soft tissues suggesting necrosis in mucormycosis
(see Figs. 7.7A and B).
• Mucor may also cause adjacent skull base osteomyelitis with lysis and
sequestrum formation (Fig. 7.11).
Fig. 7.11: Invasive fungal sinusitis (mucormycosis). Post-functional endoscopic sinus
surgery (FESS), residual mucosal thickening left maxillary and sphenoid sinus. Osteitis of
maxilla and sphenoid (arrows) with sequestrum formation (arrowhead).
■ Dierential diagnosis:
• It is dicult to dierentiate fungal sinusitis from invasive bacterial
forms.
• As fungal infection has a propensity to inltrate the vessels, on
intracranial spread these are more likely to cause thrombosis and
resultant infarctions, hemorrhages and even pseudoaneurysms.
• Hypointense signal on T2WIs suggests a fungal etiology.
Chronic Invasive Fungal Sinusitis
■ e term chronic is used for the more indolent form of the disease
(duration more than 4 weeks)
■ It is of two forms (Table 7.1): With or without granulomas, with the former
being called chronic granulomatous invasive fungal sinusitis.2
■ e comparison between AFS and chronic invasive fungal sinusitis has
been detailed in Table 7.27 and illustrated in Figures 7.12A to F.
Chronic granulomatous invasive fungal sinusitis:
■ Slow, protracted course similar to the nongranulomatous form.
■ Occurs in immunocompetent patients and the symptoms are similar to
chronic sinusitis.
107Chapter 7 Imaging in Fungal Sinusitis
Table 7.1: Chronic invasive fungal sinusitis: granulomatous
versus nongranulomatous disease.
Granulomatous Nongranulomatous
Patient prole Immunocompetent Immunocompromised
Endemic areas Southeast Asia and Africa –
Organism Aspergillus avus Aspergillus fumigatus
Imaging • Usually localized to one or
two sinuses
• Extrasinus soft tissue often
more than intrasinus soft
tissue
• Similar to acute invasive fungal
sinusitis
• Calcication more frequent and
more dense
Section 2 Inammatory Nasal Conditions108
Table 7.2: Comparison between allergic fungal sinusitis and
chronic invasive fungal sinusitis.
Key features Allergic fungal sinusitis Chronic invasive fungal sinusitis
Clinical presentation Nasal/Sinus symptoms
predominate
Diplopia/decreased vision
maybe seen
Facial swelling not seen Facial swelling; decreased
Cranial spread infrequent Seizures/altered sensorium more
Examination Nasal polyps Maybe present/absent
Organism Aspergillus avus A. avus
HPE Allergic mucin, Charcot
Leyden crystals, eosinophilic
debris, fungal hyphae, no
invasion
Distribution Bilateral with involvement
of multiple sinuses more
frequent
Expansion of
involved sinus
Seen Normal size sinus
7
Maybe present/absent
Proptosis/decreased vision/
diplopia
sensation
frequent
Inammatory inltrate,
neutrophilic, fungal hyphae with
invasion
More often unilateral with
involvement of few sinuses
Bone erosion Expansion with thinning
of overlying cortex,
Demineralization of thinned
Bone erosions seen at limited
sites corresponding to the site of
extrasinus extension
cortex appears as erosion
Extrasinus spread Limited, focal Extensive. Extrasinus soft tissue
often exceeds that within the
sinus
CT morphology Heterogenous
Central hyperdense areas
Homogenous
Hyperdensities seldom seen
with peripheral low density
MRI
T1WI Intermediate Low
T2WI Low Low
Post-contrast T1WI Mucosal enhancement seen Entire soft tissue enhances
(CT: Computed tomography; MRI: Magnetic resonance imaging; T1WI: T1 weighted image).
109Chapter 7 Imaging in Fungal Sinusitis
A
C
B
D
E
Figs. 7.12A to F: Allergic fungal sinusitis (AFS) (A, C, and E) versus chronic invasive
fungal sinusitis (CIFS) (B, D, and F). Bilateral and hyperdense contents (arrow in A) in AFS;
Unilateral and soft tissue density (arrow in B) in CIFS. Limited extrasinus spread (arrow in
C) in AFS; Extensive soft tissue spread to orbit and infratemporal fossa (arrow in D) in CIFS.
Mild expansion with demineralization of ethmoid trabeculae (arrow in E) in AFS; Erosion of
maxillary bone with reactive sclerosis of zygomatic bone (arrow in F) in CIFS.
F
Section 2 Inammatory Nasal Conditions110
A
Figs. 7.13A and B: Chronic granulomatous invasive fungal sinusitis (Mucorale sp.).
(A) Soft tissue in right maxillary sinus (arrow). Extrasinus spread to orbit, retroantral fat and
masticator space (asterisk); and (B) Erosion of bony margins (arrowhead) and sclerosis of
zygomatic bone (black arrow).
A
Figs. 7.14A and B: Chronic Granulomatous invasive fungal sinusitis: magnetic
resonance imaging (MRI) (same patient as in Figs. 7.12A to E). (A) Sinus soft tissue is
intermediate signal intensity (white arrow). Extrasinus soft tissue (orbit and infratemporal
fossa): T2 hypointense (black arrow) (B) with contrast enhancement (asterisk).
B
B
■ Highest reported prevalence is in Southeast Asia and Africa
■ Causative agents: Aspergillus sp.; most frequent being Aspergillus avus
■ Histopathology shows noncaseating granulomas with ndings of fungal
invasion.
■ Imaging ndings:
• Similar to other forms of chronic invasive fungal sinusitis.
• Nonspecic appearance.
• Distribution: Usually a single or two sinuses involved.
• No sinus expansion seen.
• Bone erosion more localized but often extrasinus involvement of
the disease is more extensive than the intrasinus extent (Figs. 7.13A
and B).
• MRI: Better delineates the soft tissue extension (Figs. 7.14A and B).
Low signal intensity on T2WIs is characteristic.
BA
Figs. 7.15A and B: Chronic nongranulomatous invasive fungal sinusitis (aspergillosis).
(A) Postoperative case of invasive aspergillosis. Extrasinus homogenous soft tissue in left
orbit, infratemporal fossa (black arrow); and (B) Lytic destruction of left sphenoid bone (white
arrow).
Chronic nongranulomatous invasive fungal sinusitis:
■ is form also primarily occurs in immunocompromised patients.
■ Symptoms are similar to non-fungal chronic rhinosinusitis but showing
a poor response to treatment.
■ May present with orbital apex syndrome.
■ Common agents: Aspergillus sp. (especially A. fumigatus).
■ Imaging:
• Findings are similar to the acute invasive forms. Extrasinus extension
may also be seen (Figs. 7.15A and B).
• However, calcication if seen is dierent in the two forms; with
punctate calcications being seen in the acute forms, while more
dense and coarse calcication is seen in the chronic form. Also, it is
seen more frequently in the chronic disease.
111Chapter 7 Imaging in Fungal Sinusitis
CONCLUSION
Fungal sinusitis has protean manifestations but with several highly suggestive
radiological signs.
REFERENCES
1. Chakrabarti A, Denning DW, Ferguson BJ, et al. Fungal rhinosinusitis: a categorization and denitional schema addressing current controversies. Laryngoscope.
2009;119:1809-18.
2. Raz E, Win W, Hagiwara M, et al. Fungal Sinusitis. Neuroimaging Clin N Am.
2015;25:569-76.
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