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Available online at ScienceDirect www.sciencedirect.com

Original Article

CNS aspergilloma mimicking tumors: Review of CNS

infection imaging characteristics in the immunocompetent population

a b,∗ c a

Devendra Kumar , Pankaj Nepal , Sumit Singh , Subramaniyan Ramanathan , Maneesh

d e e f

Khanna , Rakesh Sheoran , Sanjay Kumar Bansal , Santosh Patil

a

Al wakra Hospital, Hamad Medical Corporation, Doha, Qatar

b

Metropolitan Hospital Center, New York Medical College, NY, USA

c

University of Alabama, Alabama, USA

d

Hamad Medical Corporation, Doha, Qatar

e

Neurociti Hospital, Ludhiana, Punjab, India

f

Department of Radiodiagnosis, JN medical College, Karnataka, India

a

r t i c l e i n f o

a b s t r a c t

Article history: Background and purpose. – CNS is very rare and difficult to diagnose clinically and on imaging.

Available online xxx

Our objective was to elucidate distinct neuroimaging pattern of CNS aspergillosis in the immunocompe-

tent population that helps to differentiate from other differential diagnosis.

Keywords: Methods. – Retrospective analysis of brain imaging findings was performed in eight proven cases of cen-

Central nervous system (CNS)

tral nervous system aspergillosis in immunocompetent patients. Immunocompetent status was screened

Aspergillosis

with clinical and radiological information. Cases were evaluated for anatomical distribution, T1 and T2 sig-

Immunocompetent

nal pattern in MRI and attenuation characteristics in CT scan, post-contrast enhancement pattern, internal

inhomogeneity, vascular involvement, calvarial involvement and concomitant paranasal, cavernous sinus

or orbital extension. All patients were operated and diagnosis was confirmed on histopathology.

Results. – The age range was 19–50 years with mean age of 33.7 years. Concomitant sinonasal disease

was seen in six patients (75%). Three patients had orbital extensions. Most of the lesions (n = 7) were pro-

foundly hypointense in T2-weighted imaging. The most common enhancement pattern was bright, solid

and homogenous enhancement (n = 7). Cavernous extension with ICA encasement was always associated

with paranasal sinus disease. Six patients showed demineralization or complete resorption of involved

bone. All of the fungal masses appear hyperdense on available CT scan images.

Conclusion. – CNS aspergillus infection in immunocompetent patients has distinct imaging features as

compared to CNS aspergillosis in immunocompromised patients. A high index of suspicion in proper

clinical settings, even with immunocompetent status and typical imaging features allow us to diagnose

CNS aspergillosis in such patients.

© 2017 Elsevier Masson SAS. All rights reserved.

Introduction of central nervous system (CNS) aspergillosis can be attributed

to the use of immunosuppressive drugs, increased number of

Aspergillosis is caused by ubiquitous and saprophytic fun- solid organ and hematological malignancies as well as spread of

gus of Aspergillus species. The most common human pathogen is the human immunodeficiency virus (HIV) [2,3]. CNS aspergillo-

Aspergillus fumigatus. However, Aspergillus flavus and Aspergillus sis is a rare infection usually reported in immunocompromised

niger have been recorded occasionally [1]. Increasing frequency patients. The prognosis of CNS aspergillosis in such patients is dis-

mal with 85–100% mortality [4]. CNS aspergillosis is extremely

rare in immunocompetent individuals [5]. CNS infection can occur

∗ by hematogenous dissemination remotely from the , direct

Corresponding author. Metropolitan Hospital Center, New York City Health

extension from adjacent paranasal sinuses, middle ear cavity and

Metropolitan Hospital Center, 1901, First Avenue, New York, NY 10029, USA.

E-mail addresses: [email protected] (D. Kumar), [email protected] orbits or from post-surgical procedures [6,7]. Clinical diagnosis is

(P. Nepal), [email protected] (S. Singh), [email protected]

challenging due to non-specific presenting signs and symptoms

(S. Ramanathan), [email protected] (M. Khanna),

[6]. A prompt diagnosis leading to surgical resection and aggres-

[email protected] (R. Sheoran), [email protected]

sive antifungal treatment is required to limit the high mortality

(S.K. Bansal), [email protected] (S. Patil).

https://doi.org/10.1016/j.neurad.2017.11.001

0150-9861/© 2017 Elsevier Masson SAS. All rights reserved.

Please cite this article in press as: Kumar D, et al. CNS aspergilloma mimicking tumors: Review of CNS aspergillus infection imaging

characteristics in the immunocompetent population. J Neuroradiol (2017), https://doi.org/10.1016/j.neurad.2017.11.001

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Table 1

Imaging features of fungal granuloma.

S.N Age/sex Localization T2 feature Enhancement pattern Vascular involvement Bone involvement

1 37/M Orbital apex, PS T2 hypointense Solid Encased but patent ICA RD and CR

and CS

2 50/F Orbital apex, PS IFG, hypointense Solid, PME Encased but patent ICA RD and CR

and CS

3 24/M MCF, PS T2 hypointense rim Solid NA NA

4 40/F MCF, PS, CS IFG, T2 hypointense Solid, PME Encased but patent ICA RD and CR

5 24/M MCF, PS, CS IFG, T2 hypointense Solid Encased but patent ICA RD and CR

6 20/F ACF, CS, pituitary IFG, T2 hypointense Solid, PME Thrombosed ICA with MCA infarct RD and CR

7 30/M PS, Mastoid, CS T2 hyperintense Diffuse heterogeneous Thrombosed ICA with ACA and Permeative destruction of

enhancement MCA watershed base of skull bones

8 45/M ACF, MCF IFG, T2 hypo Solid, PME NA NA

M: male; F: female; PS: paranasal sinus; CS: cavernous sinus; ACF: anterior cranial fossa; MCF: middle cranial fossa; IFG: intracranial fungal granuloma; RD: reactive

demineralization; CR: complete resorption; PME: pachymeningeal/dural enhancement.

•

associated with the infection. Moreover, the classical neuroimag- axial diffusion-weighted echo planar sequence (3116 ms

ing findings of CNS aspergillosis described in immunocompromised TR/81 ms TE/2NEX) and;

•

patients are often not seen in immunocompetent individuals mak- post-contrast T1-weighted images were obtained in three

ing the diagnosis even more difficult. orthogonal planes after administration of 0.2 mL/kg of gadobe-

Recognizing the typical and atypical imaging features of CNS nate dimeglumine (Multihance; Bracco Diagnostics Incorpora-

aspergillosis allows for early and aggressive management of oth- tion, Monroe, NJ, USA).

erwise rapidly fatal infections. As we know CNS aspergillosis in

immunocompetent individuals is very rare, although few of the In all sequences, except susceptibility-weighted sequence, the

studies and cases have been reported in the literature [1,5,7–12,14], slice thickness was 5 mm and interslice gap of 1–2 mm. Due to

however the discussion of a distinct neuroimaging pattern of CNS volume acquisition, the slice thickness in susceptibility-weighted

aspergillosis in immunocompetent population and its difference sequences was 1 mm. In all sequences, the field of view was 16 to

with immunocompromised patients have not been specifically 24 cm and matrix size was 200–256 × 170–198, except DWI, which

elaborated. In this article, we describe magnetic resonance imaging had an image matrix of 144 × 113.

(MRI) and computed tomography (CT) findings of biopsy-proven CT of the head was performed in 3 patients. Routine CT head

CNS aspergillus infection in eight immunocompetent patients. Case were obtained using GE 16 slice multidetector scanner (General

history and imaging findings of five patients are discussed in detail. Electric, Waukesha, Wisconsin, USA). The scanning parameters for

head CT were 120 Kvp and variable mA depending on SD setting.

Three neuroradiologists with more than 5 years of experience

Material and methods

in neuroimaging reviewed images by consensus. All cases were

evaluated for anatomical distribution; T1 and T2 signal pattern

The institutional review board approved this retrospective

in MRI and attenuation characteristics in CT scan, post-contrast

study. We identified and included eight immunocompetent

enhancement pattern, internal inhomogeneity, vascular involve-

patients from neuroradiology and surgery databases from January

ment, calvarial involvement and concomitant paranasal, cavernous

2010 to January 2014 for a period of 4 years. The clinical data were

sinus or orbital extension. All patients were operated and diagnosis

obtained from electronic medical records. Immunocompetent sta-

was confirmed on histopathology.

tus was screened with clinical and radiological information. The

patients in our study had not received chemotherapy, steroids,

Case review

or other immunosuppressive agents. Patients were not included

if they had a diagnosis of any known malignancy, chronic liver

The clinical detail and imaging features of all patients are sum-

disease, end-stage renal failure, diabetes mellitus, HIV infection,

marized in Table 1. In the interest of scope of the article and to

or congenital immunodeficiency. Patients not meeting the criteria

avoid repetition of imaging findings, we describe the case history

were excluded.

and imaging findings of 5 out of 8 patients in detail.

MRI brain with contrast was performed in all patients. CT scan of

head was done on 3 patients. All MRI scans were performed on 1.5-T

Case 1

Achieva scanners (Philips Healthcare, Andover, MA, USA). Standard

A 17-year-old female presented with generalized acute

8-channel head coil was used for signal acquisition.

headache and diminution of vision had a clinical diagnosis of retro-

bulbar neuritis. Lab work revealed leukocytosis. Blood sugar was

Standard brain imaging protocol

normal. Contrast enhanced magnetic resonance imaging (CEMRI)

revealed a mass along the right planum sphenoidale with exten-

The standard brain imaging protocol consist of:

sion into the right sphenoid sinus and the anterior pituitary gland

(Fig. 1).

•

sagittal T1-weighted spin echo (375–750 ms repetition time

The pituitary infundibulum was thickened and showed loss

[TR]/9.5 to 25 ms time to echo [TE]/1 number of excitations

of expected inferior tapering. The mass was predominantly

[NEX]);

hypointense on T2-weighted images, intermediate signal intensity

•

axial and coronal T2-weighted fast spin echo (2500–7000 ms

on T1-weighted images and showed intense contrast enhancement.

TR/80–102 ms TE/1 NEX);

Internal carotid arteries flow voids were preserved. The location

•

fluid attenuated inversion recovery sequence (11,000 ms

and MR signal characteristics were suggestive of meningioma; but

TR/140 ms TE/2800 ms inversion time/2 NEX);

the pituitary stalk, sphenoid sinus invasion and anterior pituitary

•

axial susceptibility-weighted sequence on Philips (35 ms

extension was atypical for meningioma. Other possibilities like

TR/20 ms TE/1 NEX);

hematological tumors, Langerhans cell histiocytosis,

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characteristics in the immunocompetent population. J Neuroradiol (2017), https://doi.org/10.1016/j.neurad.2017.11.001

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Fig. 1. A, B, C, D. 17-year-old female with planum sphenoidale fungal granuloma with pituitary gland and infundibular involvement. Coronal T2-weighted image (A) shows

hypointense extra-axial fungal granuloma along the planum sphenoidale. Diffuse contrast enhancement noted in the post-contrast sagittal (B) and coronal T1-weighted

images (C) with continuous extension to pituitary gland and stalk. Pituitary stalk is thickened and irregular in outline. Repeat post-contrast T1-weighted image (D) after

24 hours due to sudden development of left hemiplegia demonstrate right ICA occlusion resulting in right MCA territory infarct (not shown).

and fungal infection were considered. MRI was repeated the fol- Case 3

lowing day after the patient developed left sided hemiparesis. The A 50-year-old female presented with right orbital pain for 3

MRI showed complete intracranial ICA occlusion and right MCA months. Physical examination revealed ophthalmoplegia, ptosis

infarct. The vascular invasion was suspicious for fungal infection. and visual loss. Lab findings were within normal limits. Contrast

Endoscopic trans-sphenoid biopsy and curettage was done. His- MRI brain showed heterogeneous, T2 hypointense mass at the

topathology revealed fungal infection by A. fumigatus. Antifungal right orbital apex region with heterogeneous enhancement. Orbital

treatment by intravenous amphotericin was started. apex structures were compressed. There was ipsilateral spheno-

ethmoidal sinusitis (Fig. 4). The imaging possibilities included

atypical granulomatous infection including fungal and tuberculo-

sis, metastasis, pseudotumor and lymphoma. Endoscopic biopsy

was done via the right sphenoid sinus, which confirmed the

Case 2 aspergillosis.

A 48-year-old female presented with blurring of vision and

right-sided body weakness since 4 weeks. She had right frontal

headache for 6 months. On examinations, she had right VI nerve

Case 4

palsy and right body weakness. Her lab investigations were within

A 30-year-old young male presented with severe generalized

normal limits. CT head showed a hyperdense mass in the right

headache, altered sensorium, rhinorrhea, diminishing vision and

para-cavernous region extending to the posterior fossa prepon-

generalized weakness. On examination, the patient had multiple

tine region (Fig. 2). The mass caused smooth erosion of sphenoid

cranial nerve palsies (III, IV, V, and VI). The lab work was significant

sinus lateral wall. MR brain confirmed a profoundly T2 hypointense,

for leukocytosis, and raised inflammatory markers. Initial contrast

para-cavernous mass having diffuse, homogenous enhancement.

CT showed extensive permeative lytic destruction of skull base and

The mass was encasing the ICA but not invading it. There was an

opacification of the sphenoid sinuses. There was destruction of the

associated T2 hypointense linear thickening in the lateral sphenoid

sphenoid sinus septum and erosion of its margins. T2-weighted

sinus wall. The sinus was otherwise filled with T2 hyperintense sec-

MRI images showed diffuse hyperintense signal in mastoid and

retions. The CT and MRI imaging features resembled meningioma;

sphenoid sinuses extending to the para-cavernous region (Fig. 5).

but the bone and cavernous sinus invasion were atypical. The dif-

Post-contrast MRI showed intensely enhancing soft tissue in the

ferential was widened to include neurogenic tumor, pseudotumor,

spheno-ethmoidal sinuses extending to the bilateral cavernous

lymphoma and fungal infection. The mass lesion was surgically

sinus. The left ICA was completely occluded. There was left ACA and

removed through right temporal approach. Histopathology con-

MCA watershed infarct. The CT and MRI findings were suggestive

firmed the diagnosis of aspergilloma (Fig. 3).

of a locally aggressive process possibility representing hematologic

Please cite this article in press as: Kumar D, et al. CNS aspergilloma mimicking tumors: Review of CNS aspergillus infection imaging

characteristics in the immunocompetent population. J Neuroradiol (2017), https://doi.org/10.1016/j.neurad.2017.11.001

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Fig. 2. A, B, C, D, and E. 48-year female with right para-cavernous fungal granuloma with extension into right CP angle cistern. Axial non-contrast CT images (A, B) show

hyperdense fungal granuloma with smooth bone resorption and scalloping. Fungal granuloma is profoundly hypointense in axial T2-weighted image (C), isointense in axial

T1-weighted image (D) and shows intense contrast enhancement in post-contrast axial T1-weighted image (E). Mucosal thickening is noted in the sphenoid sinus.

Fig. 3. A, B. A. Photomicrographs showing histopathologic features of Aspergillus granuloma: granulomatous inflammation characterized by giant cells, lymphocytes, plasma

cells and fibrosis. (Hematoxylin and eosin, original magnification, × 100). B. Broad, septate and branching fungal hyphae with right angle branching, PAS stain, original

magnification × 1000.

malignancy, metastasis or infection possibly fungal or granuloma- sphenoid sinus with secretions. The solid T2 hypointense intraor-

tous in origin. An endoscopic trans-sphenoidal biopsy was made bital intraconal mass simulated a hematologic neoplastic mass

yielding the diagnosis of aspergillus infection. (granulocytic sarcoma or lymphoma), especially in association

with pachymeningeal enhancement. Other imaging possibilities

Case 5 included were metastasis, meningioma or neurogenic tumor. Endo-

A 50-year-old male presented with right orbital pain and vision scopic trans-sphenoidal biopsy was performed which established

disturbance for few months. Laboratory findings were within the diagnosis of aspergilloma.

normal limits. Contrast MRI brain showed a well-defined and

diffusely hypointense mass in T2-weighted images in the right Results

orbit, intraconal compartment (Fig. 6). The mass extended pos-

teriorly to the orbital apex and right para-cavernous region. The The age range was 19–50 years with mean age of 33.7 years.

mass showed diffuse contrast enhancement. There was thick- Six out of 8 patients (75%) were male. Headache (n = 7), visual dis-

ening and pachymeningeal enhancement in the adjacent right turbances (n = 5), weakness (n = 4) and confusion (n = 4) were the

middle cranial fossa. Mucosal thickening was noted in the right primary presenting manifestations. Brain MRI was performed in all

Please cite this article in press as: Kumar D, et al. CNS aspergilloma mimicking tumors: Review of CNS aspergillus infection imaging

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Fig. 4. A, B. 37-year male with orbital apex fungal granuloma. Axial T2-weighted image (A) shows hypointense fungal granuloma with intense contrast enhancement in axial

T1-weighted post-contrast image (B).

Fig. 5. A, B. 30-year male with diffuse permeative destruction of base of skull bones with sinusitis. Bone window axial CT image (A) shows permeative destruction of base of

skull bones. Diffuse enhancement is demonstrated in sphenoid sinus with extension to the both cavernous sinus and loss of flow void in left ICA in post-contrast T1-weighted

image (B).

Fig. 6. A, B. 50-year-old female with intraconal and para-cavernous fungal granuloma with focal pachymeningeal enhancement. Axial T2-weighted image (A) shows

profound hypointense intraconal fungal granuloma. T1-weighted contrast enhanced image (B) demonstrates heterogeneous peripheral contrast enhancement with focal

leptomeningeal enhancement in middle cranial fossa.

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Table 2

Comparison between immunocompromised and immunocompetent patient populations.

Features Immunocompromised Immunocompetent

1) Source and primary focus Hematogenous spread mostly from lungs Extension through paranasal sinus most common

2) Aspergillus, mucor, cryptococcus, candida Mostly Aspergillus

3) Imaging pattern Ring-enhancing lesions – abscess, meningitis, Intra- and extra-axial (solid T2 hypointense intracranial fungal

meningoencephalitis granuloma), focal and thick pachymeningeal enhancement

4) Localization Gray-white matter junction and supratentorial brain Anterior and middle cranial fossa near the orbit and paranasal

parenchyma sinus

5) Hemorrhage and mycotic Common due to vasculitis Uncommon

aneurysm

6) Infarct Smaller infarcts due to vasculitis Territorial infarct by thrombosed ICA

7) Cavernous sinus, orbit, orbital Not common Commonly involved

apex involvement

8) Calvarium destruction Uncommon, common mode is hematogenous spread Reactive resorption to permeative destruction

8 patients preoperatively, and CT was performed preoperatively in walls. A similar study by Siddiqui et al. [7], which is probably one of

3 patients. Post-operatively the diagnosis was made by histopath- the largest studies of CNS aspergillosis in 20 immunocompetent

ology in all patients. individuals, showed that all of the patients had paranasal sinus

On imaging, there was concomitant sinonasal disease in six involvement. One of the patients in our study had both mastoid

patients (75%). Three patients had orbital extensions. All orbital and paranasal sinus involvement. Most fungal infections essen-

extensions were associated with orbital apex, cavernous sinus and tially begin from the paranasal sinuses [4]. Imaging findings include

paranasal involvement. The most common imaging feature was mucosal enhancement of sinuses, enhancement of adjacent dura

a solid granulomatous lesion extending from involved paranasal and subdural empyema. The intracranial and intraorbital infections

sinuses. The most common enhancement pattern was bright, solid in three cases were most likely by contiguous spread. All intraor-

and homogenous (n = 7). One patient with mastoid region, sphe- bital extensions were associated with orbital apex, cavernous sinus

noid sinus and cavernous sinus involvement had diffuse and patchy and paranasal sinus involvement.

heterogeneous enhancement. The same patient had T2 hyperin- The radiological appearance of CNS aspergillosis is vari-

tense signal in the involved area. All of the other lesions (n = 7) able and depends upon the patient’s immune status. We

showed profound hypointense signal in T2-weighted imaging. All have observed difference in MRI imaging appearance of CNS

of the lesions had intermediate or isointense signal in T1-weighted aspergilloma in immunocompetent and immunocompromised

imaging. Cavernous extension with ICA encasement was a fea- individuals (Table 2). The classical findings described in immu-

ture in all six patients with paranasal sinus disease. This had nodeficient patients are multiple ring enhancing lesions, abscess

serious consequences in two patients who developed ICA thrombo- formation, meningitis/meningoencephalitis, and small infarcts

sis with malignant MCA infarct and ACA-MCA watershed infarcts with or without hemorrhage due to vasculitis and mycotic

respectively. Four patients had adjacent pachymeningeal (dural) aneurysm [17–19]. Hematogenous dissemination is more common

enhancement. One of the patients had an atypical finding of pitu- in immunocompromised patients with cerebral invasion. Thus, the

itary gland and infundibulum involvement; a similar atypical case findings are distributed along the corticomedullary junction and

has not been reported previously in the literature. The most com- perforating artery territories in the supratentorial area [19]. CNS

mon localization was middle cranial fossa (n = 4), followed by aspergillosis in immunocompetent individuals presents as intrace-

anterior cranial fossa (n = 3), near the paranasal sinuses. Six patients rebral, intracranial-extradural or invading orbit and/or skull base

showed demineralization or complete resorption of involved bone. [7]. Fungal invasion is common in immunocompetent patients and

One patient showed a lytic permeative destructive pattern of the produces elastase causing thrombotic occlusion of small arterial

skull base. All of the fungal masses appeared hyperdense on CT branches, which leads to smaller cortical and subcortical infarcts

images available for three patients. with or without hemorrhage. There is a tendency to involve major

vessels around the cavernous sinus [4,20]. In our view, cavernous

Discussion extension with ICA encasement was a frequent feature with con-

comitant paranasal sinus disease. Thus, major territorial infarct due

Aspergillus infection in immunocompetent patients is rare but to ICA, malignant MCA infarct and ACA-MCA watershed infarcts are

has been described in the tropical and subtropical areas. Hot and dry common features in immunocompetent patients.

Indian subcontinent environment with abundance of Aspergillus Our study demonstrates the fungal granuloma appearing dif-

spores, poor nutritional status, injudicious use of steroids and anti- fuse and profoundly hypointense on T2-weighted imaging. The T2

tubercular drugs might be the possible explanation of infection in hypointense signal correlates with the presence of paramagnetic

immunocompetent patients in this geographical region [1,2,12,13]. elements like iron, manganese, magnesium, zinc that are essen-

Chronic granulomatous invasive fungal rhinosinusitis also known tial for hyphal growth of the fungi but may also be related

as primary paranasal granuloma can occur in immunocompetent to blood breakdown products [1,6,7,21,22]. In immunocompro-

patients, and A. flavus is most common organism to cause sinonasal mised patients, CNS aspergillosis commonly manifests as a fungal

disease [12]. abscess with a central area of necrosis (seen as hyperintense or

CNS aspergillosis of sinonasal origin has been reported con- intermediate signal in T2 images) followed by the intermediate

sequent to local infection of the ear or paranasal sinuses [14]. layer composed of a dense hyphal rim which appears as a T2

With nose and paranasal sinuses involvement the disease has a hypointense rim, surrounded by perilesional edema [6]. Aspergillus

very high mortality [15,16]. Preexisting paranasal sinus involve- vasculopathy may lead to cortical/subcortical infarcts seen as T2

ment may predispose to intracranial involvement by providing a hyperintensities with or without areas of bleeding. Similar to fun-

source and also a conduit into the cranium through focal bone gal sinusitis, aspergillus granuloma has a characteristic low T2

destruction, tiny foramina or venous channels even without bone hyperintense signal, but is diffuse rather than peripheral [7,23].

destruction. Six out of eight patients in our study had concomitant CT imaging is non-specific; the fungal mass mostly appears hyper-

paranasal sinus diseases, all with focal bone destruction of sinus dense due to the calcium salts and metal ions deposited in necrotic

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areas [24]. Other imaging features in CT include paranasal sinusitis is not a feature of meningioma. Both the aspergilloma and menin-

and areas of bony destruction. gioma appear hyperdense in non-contrast CT brain scans with

The most common pattern of contrast enhancement in our study adjacent hyperostosis or lytic destruction of the skull. In contrast

was a solid and homogenous pattern, with the exception of one to aspergilloma, meningioma appears isointense to gray matter on

patient having diffuse patchy enhancement. Lesion enhancement both T1- and T2-weighted sequences [30,31]. Post-contrast, both

correlates with the immunocompetence level [6]. CNS aspergilloses pathologies enhance homogenously. One of the main differenti-

has variable appearance in immunocompromised patients. The ating features is aspergilloma appearing profoundly hypointense

most common pattern is thick and irregular, heterogeneous ring- on T2W imaging. Fibrous and psammomatous meningioma can

like enhancement due to abscess cavity [6]. It may show no have a lower T2 signal like aspergilloma, however these sub-

contrast enhancement usually referring to dismal prognosis. How- groups of meningioma do not show homogenous, avid contrast

ever, solid and homogenous enhancing lesions with paranasal enhancement, and adjacent sinus involvement [32]. Meningioma

sinus involvement referred to as aspergilloma is most common in demonstrates sunburst flow void pattern on MR imaging [33].

immunocompetent individuals. Dural enhancement is usually seen Hyperdense appearance on CT, hypointense signal in T2-weighted

adjacent to infected paranasal sinuses, which represents a direct imaging, extra-axial location and diffuse enhancement can be seen

extension of the infection [23]. Four of our patients had adjacent with meningioma; however bony destruction, sinus opacification,

dural enhancement, which is a common finding in sinonasal dis- cavernous sinus and arterial invasion can help in differentiation

ease. The aspergilloma in immunocompetent individuals shows and arriving at the diagnosis.

bright and homogenous enhancement with predilection to the Lymphoma also can involve the paranasal sinuses with

anterior and middle cranial fossa [2,7]. coexisting intracranial component, which may be difficult to

These imaging features lead to wide differential consideration differentiate from aggressive fungal infection [34,35]. The lym-

and include metastases, meningioma, lymphoma, granulocytic sar- phomatous mass also appears hyperdense on CT and hypointense

coma, tuberculoma, aggressive sinonasal tumor and neurogenic on T2-weighted MR imaging due to high cellularity and a high

tumors (schwannomas). The differential considerations change nuclear/cytoplasmic ratio. They exhibit homogenous post-contrast

with different presentations as we discussed above in the case enhancement similar to aspergilloma, however, involvement of

histories. In the young patient with diffuse permeative destruc- paranasal sinuses, encasement of ICA and adjacent calvarial

tion of the base of skull bone, the differential included metastases. involvement is uncommon. MR spectroscopy demonstrates ele-

The closest resemblance in our study was with meningioma and vated lipid peaks and high Cho/Cr ratios where DWI shows

hematological malignancy, including lymphoma. Fungal granulo- diffusion restriction, which can be differentiating features from CNS

mas present as enhancing masses sometimes with enhancement aspergilloma [36].

of the adjacent to the dura producing “dural tail sign” [25,26]. Both fungal infections and sinonasal carcinoma present with

similar symptoms of rhinosinusitis, epistaxis, loss of vision and

Differential diagnosis cranial nerve involvement. Most often, carcinomas arise from

the maxillary sinuses followed by the ethmoid sinuses, nasal

Central nervous system and sinonasal involvements can present cavity and a rare involvement of frontal and sphenoid sinuses

in infectious, neoplastic and inflammatory pathologies. CNS [37]. Nasopharynx, skull base and sphenoid sinus tumors may

aspergillosis in immunocompetent individuals has specific features extend intracranially with perineural involvement, aggressive bony

that differentiate it from other mimickers, which are elaborated in destruction and metastasis. Benign sinonasal tumors can cause

this section. bone remodeling and sclerosis, where malignant tumors cause

aggressive destruction in the sinus wall and skull base and orbit

Infectious diseases bones, which are best evaluated on CT scan. They are generally

hypo to isointense to muscles on T1-weighted images and iso- to

The fungal elements appear hypointense on T2-weighted (T2W) hypointense on T2-weighted images due to high cellularity and

MR sequence. Sinonasal has been also reported in less water content within the tumor [38]. They show moderate to

immunocompetent individuals similar to CNS aspergillosis [27]. intense heterogeneous post-contrast enhancement. The extensive

The infarcted mucosa appears hypointense on T2W imaging and bone destruction, cervical lymphadenopathy and heterogeneous

may lead to a restricted diffusion. Mucormycosis generally involves post-contrast enhancement are differentiating features from the

nasal cavity with features of mucosal infarction, which does not aspergilloma.

show homogeneous enhancement. Tuberculomas present either Dural metastasis is often solitary and arises most commonly

single or multiple lesions, with variable signal intensities on MRI. from , breast or prostate. The lesions are typically T2 hyper-

The solid tuberculoma appears hypointense on T2W images. The intense but signal characteristics depend upon the cellularity of

T2 hypointensity depends on stage of caesation, associated fibro- the tumor and adjacent osseous invasion may be evident. Dural

sis and macrophage infiltration. Non-caseating tuberculomas have metastasis can present with thick linear or nodular enhancement of

similar imaging features with other infectious granulomas such as the dura and the tumor usually shows avid contrast enhancement

aspergillomas. In vivo spectroscopy, which shows lipid peak in T2 due to breach of the blood-brain barrier [39]. Malignant periph-

hypointense tuberculomas, can differentiate them accurately [28]. eral nerve sheath tumors (MPNST) are large infiltrative lesions with

erosions of skull foramina and remodeling of adjacent bones. How-

Neoplastic differentials ever, the nerve sheath tumors are T2 hyperintense in contrary to

aspergillomas, which are profound T2 hypointense [40].

Meningioma can mimic intracranial aspergilloma. It is the most

common, benign primary brain tumor which presents as an extra- Inflammatory differentials

axial mass near the cerebral convexity in the parasagittal region,

sphenoid wing and the juxta sellar area. Rarely, meningioma can Inflammatory pseudotumors of orbital, paranasal sinuses and

arise in the orbit and paranasal sinuses [29]. Meningioma can brain are hypointense on T2-weighted images. They may show

extend into the cavernous sinus and prepontine cistern via the marked post-contrast enhancement [41]. Sinonasal involvement

porous trigeminus. It can constrict the cavernous ICA mimicking the may be associated with bony erosions, remodeling and destruc-

angioinvasive nature of aspergilloma, however cerebral infarction tion. However, they show significant improvement with steroid

Please cite this article in press as: Kumar D, et al. CNS aspergilloma mimicking tumors: Review of CNS aspergillus infection imaging

characteristics in the immunocompetent population. J Neuroradiol (2017), https://doi.org/10.1016/j.neurad.2017.11.001

G Model

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Disclosure of interest

[32] Liu L, Lu Y, Peng W, Geng D, Wen J, Xiong J, et al. Imaging features of intracra-

nial psammomatous meningioma. J Neuroradiol 2017, http://dx.doi.org/

The authors declare that they have no competing interest. 10.1016/j.neurad.2017.06.003 [pii: S0150-9861(16)30234-6].

[33] Wang C, Xu Y, Xiao X, Zhang J, Zhou F, Zhao X. Role of intratumoral flow void

signs in the differential diagnosis of intracranial solitary fibrous tumors and

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characteristics in the immunocompetent population. J Neuroradiol (2017), https://doi.org/10.1016/j.neurad.2017.11.001