Head David M. Yousem, William E. Bolger,

Inverted .#{149}

with

MD MD

#{149}

W. Fellows,

#{149} Haskins

Douglas

Kashima,

Papilloma:

MR

Imaging

Radiology

1992;

#{149} David S. James

Evaluation

Nose, neoParanasal

#{149}

#{149}

S

recent studies have attempted to differentiate the besions that occur in the sinonasal cayity by

means

(MR)

imaging

teristics

(1-3).

of magnetic

signal

and

enhancement

In general,

masses

can

the

Departments

Neuro-

radiology Section (D.M.Y.) and Otorhinolaryngology, Head and Neck Surgery (D.W.K., WEB.), Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104; and Departments of Radiology, Neuroradiology Section (D.W.F., S.J.Z.) and Otorhinolaryngology, Head and Neck Surgery (H.K.), The Johns Hopkins Hospital, Baltimore. Received April 15, 1992; revision requested May 21; revision received June 2; accepted June 22. Address reprint requests to D.M.Y. e RSNA, 1992

MATERIALS

inflammatory

be distinguished

from

ma-

by their very high signal intensity on T2-weighted images. In the sinonasab cavity, a peripheral rimenhancement pattern has been described in inflammatory mucosal disease, polyps, and mucoceles (3). A solid enhancement pattern is suggestive of malignancy. Elsewhere in the head and neck, it has been suggested that less cellular neoplasms of the parotid gland can be distinguished from more cellular, poorly differentiated counterparts on the basis of signal intensity; sions tend

the

less

differentiated

be-

to have a bower signal intensity on T2-weighted images (4-6). The inverted papibboma (IP) is a rebativeby common neoplasm of the nasal cavity, accounting for 4% of all nasal neoplasms (7). IPs generally arise along the lateral aspect of the nasal cavity but often grow into the paranasab sinuses and can be locally destructive. The importance of diagnosing IPs lies in the fact that squamous

cell

carcinoma

may

cell

carcinomas

be coexist-

because

arise

within

It is squabPs

It would be very the two neo-

a more

aggressive

therapeutic intervention at the outset would be indicated for squamous cell carcinoma. The prognostic implications and the necessity of postoperative radiation therapy are different for the two entities. To determine whether MR imaging is useful

in differentiating

and comwith those reported in

characpatterns

lignancies

mous

of Radiology,

resonance

intensity

ent in 5.5%-27% of cases (7-11). not clearly understood whether

185:501-505

ance of IP at MR imaging pare these characteristics of sinonasab malignancies the literature.

EVERAL

plasms From

W. Kennedy, MD Zinreich, MD

#{149}

or in separate sites. useful to distinguish

I

Radiology

#{149}

The authors examined the magnetic resonance (MR) appearance of inverted papillomas to determine if this histologically benign lesion could be distinguished from malignancies of the sinonasal cavity. MR images in 10 patients with histologically proved inverted papilloma were retrospeclively reviewed. The signal intensity of inverted papilbomas on short repetition time (TR) images was iso- to slightly hyperintense to muscle in all 10 patients. Inverted papillomas had intermediate signal intensity on the long TR/echo time (TE) images. The tumors were iso- or slightly hypointense to fat on long TR/short TE images. In the seven patients who received gadopentetate dimeglumine, all inverted papillomas showed solid inhomogeneous enhancement. A review of eight sinonasal malignancies showed no distinctive signal intensity or enhancement characteristics to help differentiate inverted papillomas from various malignant tumors. The authors conclude that there is no signature MR appearance for the benign inverted papilboma. The main utility of MR imaging is in defining the extent of the lesion. Index terms: Nose, MR. 23.1214 plasms, 26.369 #{149} Papilloma, 26.369 sinuses, neoplasms, 23.369

MD

MD

Neck

and

between

and sinonasal malignancies, we retrospeetiveby reviewed the MR imaging experience with IP at two institutions. Our goal was to describe the appear-

The

AND

MR images

tologically tions three

proved

of all patients

with

bPs

institu-

from

were retrospectively neuroradiobogists

S.J.Z.). The study 10 patients aged 35-70 nasal

two

his-

reviewed by (D.M.Y., D.W.F.,

population consisted of men and three women) (mean, 54 years). The

(seven years

cavity

tients;

METHODS

was

involved

extension

into

in all the

10 pa-

paranasal

sinuses

was seen in eight. Two patients had bilaterab sinonasal extension. All images were obtained at 1.5 T with a Signa

imager

(GE

Medical

Systems,

Mib-

waukee) with a quadrature head coil. TIweighted images were obtained with repetition times (TRs) of 400-850 msee and echo times (TEs) of 11-30 msee. Long TR images

were

obtained

with

TRs

of 2,500-

3,600 msec and TEs of 18-36 msee (proton density) and 80-108 msec (T2 weighted). Fast

spin-echo

laxation

(rapid

acquisition

enhancement

weighted

pulse

with

[RARE])

sequences

re-

T2-

were

used

in

three patients (12). All images were obtamed with a 256 x 128-256 matrix, infenor saturation pulses, and one or two signals mine

averaged. Gadopentetate was administered at a dose

mmob/kg

in seven

weighted

images

ately tetate

10 patients.

obtained

after administration dimeglumine, with

600-833

and

17-26

Images were sity and contrast istics. The signal compared with cosa,

of the were

and

weighted signal

images.

intensity

of the gadopenTRs and TEs of respectively.

fluid

(CSF)

for

and

T2-

proton-density,

intensity

weighted

msee,

Because on

images on

TI-

immedi-

evaluated for signal intenenhancement characterintensity of the IP was that of muscle, fat, mu-

cerebrospinal

Ti-weighted,

dimegluof 0.1

routine

fast

and

fat spin-echo

has

high T2-

intermediate spin-echo

the

signal images,

im-

IP Abbreviations:

CSF = cerebrospinal fluid, IP = inverted papilloma, RARE = rapid acquisition with relaxation enhancement, TE = echo time, TR = repetition time. cni

a.

b.

Figure

1.

Bilateral

IP in a 35-year-old

man

with

c.

nasal

congestion.

(a) Axial T2-weighted

through the nasal cavity shows a mass of heterogeneous mixed (predominantly Note the high signal intensity of obstructed secretions in the maxillary antrum moid sinuses. (b) Coronal Ti-weighted MR image (600/16) shows hypointense pointense secretions within the inferior left maxillary antrum (M). The patient side. (c) Fat-suppressed coronal MR image (800/26) obtained after administration cavity mass with gradational enhancement between the inferior right turbinate

ment

is to be contrasted

ages

of the

RARE

three

patients

were

imaging

again

with

who

evaluated

the peripheral

underwent

separately

for comparison of fat signal intensity. Contrast enhancement of the IP was assessed

for

compared mueosal classified

with adjacent inflammatory enhancement. Enhancement was as marked (enhancing as much

as inflamed

homogeneity

mucosa),

enhancement mucosa),

moderate

signal

(slight

than

were

that

evaluated

neuroradiologists

as that

after The

by consensus viewing

of

over

administra-

dimegbumine,

of mueosa).

and

(definite

increase

intensity

tion of gadopentetate less

degree

but not as sinking or mild

baseline

and

much

images

of the three the

images

to-

gether.

RESULTS

At Ti-weighted imaging, five IPs were isointense and five were hyperintense to muscle. The masses were hyperintense to CSF and hypointense to fat in all eases (Table). The proton-density images reveabed the masses to be hyperintense to CSF in all patients and isointense fat in all but two patients, in whom 502

Radiology

#{149}

to

rim enhancement

within

MR image

(TR msec/TE

intermediate) signal (M). The patient had mass (arrows) within

had previously

sinus

the lesion was hypointense to fat. The bPs were hyperintense to muscle. However, heterogeneity within the tumors was seen in eight of the 10 bPs on long TR/short TE images. On the conventional T2-weighted spin-echo images, the masses were isointense to fat in three of the seven patients and hyperintense to fat in four. On the RARE images, all three tumors were hypointense to fat but were still of intermediate signal intensity (similar to that of gray matter) (Fig 1). On T2-weighted images, besions were hypointense to CSF and hyperintense to muscle in all cases. On the long TR/TE images, septafions/ striations within the IP were seen in five of the 10 patients. Solid enhancement of the IP was seen in all 10 cases; the enhancement was heterogeneous in seven. All IPs enhanced bess than the adjacent inflammatory mucosa, which had marked enhancement, and enhancement was considered mild in two patients and moderate in five (Fig 2).

msee (arrows)

previously

undergone

both

cavities,

undergone

of contrast material and the region of the

the maxillary

intensity nasal

partial shows solid left middle

inflammatory

=

3,500/90)

in both

obtained

nasal

surgery with

even

turbinatectomy enhancement turbinate.

The

cavities.

of the ethmore

hy-

on the right of the nasal solid enhance-

secretions.

The extent of disease was confirmed with review of surgical notes. In two patients, the masses extended through the cribriform plate to the intracranial compartment. No intraparenchymal cerebral invasion was present; however, meningeal infiltration was seen at surgery. The intracranial extent of the tumor was not appreciated at computed tomography (CT) performed in these two cases at the same time as MR imaging. In one case, the mass grew into the masticator space via the pterygopabatine fossa.

One patient underwent extensive preoperative biopsies, which led to a diagnosis of IP. The postoperative surgical specimen revealed multifoeab microscopic areas of squamous cell carcinoma within the IP (Fig 3). Even in retrospect, none of the three neuroradiologists could identify the one patient with both squamous cell earcinoma and IP. In 1 year, eight patients with mabignancies of the sinonasal cavity (three esthesioneurobbastomas, two melanoNovember

1992

a.

b. Figure

2.

Right

old woman.

b. Figure 3.

(2,700/108)

d.

reveals

through

a mass

Left nasal IP with microscopic foci of squamous cell carcinoma in a 26-year-old man. (a) Axial MR image (3,500/18) through the nasal mass reveals a mass of heterogeneous intermediate signal intensity within the left nasal cavity, with extension into the left maxillary antrum. High signal intensity is seen in the obstructed secretions in the left maxillary antrum. 0’) Axial MR image (3,500/90) again shows a mass of intermediate signal intensity within the left nasal cavity, with nonaggressive expansion and deformity of the left medial maxillary sinus wall. This signal intensity would be identical to that seen with squamous cell carcinoma.

sity within right nasal

(c) Axial Ti-weighted

ing

mine

shows

Note

the

image

(600/Il)

obtained

after

administration

of gadopentetate

dimeglu-

mass extending from the left nasal cavity into the left maxillary antrum. rim enhancement of the maxillary antrum, denoting inflammatory disease as opposed to a neoplastic process. (d) Fat-suppressed coronal MR image (700/26) obtained after administration of gadopentetate dimeglumine reveals left nasal cavity enhancement with a small nodule (arrow) extending through the left maxillary sinus ostium. Opacification of the left maxillary antrum with obstructed secretions is noted. Note also the extension of the neoplasm through the enbnform plate (arrowhead) on the left side, where the low signal intensity

a solid

Intermediate

IP in a 48-year-

the

and

mass

right

antrum

of heterogeneous

signal

the right maxillary antrum cavity, with well-defined

signal

intensity

images is not always indicative malignancy. (b) Fat-suppressed image (750/26) obtained after

of contrast

MR image

maxillary

material occupying

maxillary

reveals the

right

inten-

and borders.

on 12-weighted of high-grade coronal MR administration

a solidly nasal

enhanccavity

antrum.

peripheral

of the

Multiple dominant

cortical

bone

foci of microscopic IP.

is lost.

Compare

squamous

this

with

cell carcinoma

the

appearance

were

found

of the

scattered

contralateral

within

side.

the pre-

association with human papibbomavirus-li has been proposed (ii). The IP is seen pathologically as a vascular mass with prominent mucous

mas,

nasoantral

(a) Axial 12-weighted

two

squamous

cell

carcinomas,

and one small cell carcinoma) underwent MR imaging with similar parameters as those performed for the IPs. An informal review of these cases by one neuroradiobogist revealed that three olfactory neurobbastomas (Fig 4), one melanoma, one squamous cell carcinoma, and a small cell carcinoma (Fig 5) had some of the same signal intensity characteristics and enhancement patterns as those of the bPs reported herein. The septated/striated appearance noted in five IPs was found in one squamous cell carcinoma and one olfactory neuroblastoma. The signal intensity patterns of IP and sinonasab malignancies are also compared with those reported in the literature in the following discussion.

DISCUSSION bPs are masses that typically arise along the lateral nasal wall or in the paranasab sinuses (most frequently in the maxillary antrum). Patients present with nasal congestion, epistaxis, nasal discharge, and recurrent sinusitis. bPs originate from the nasal septum in only 5.5%-18% of cases (9,i3). Bilateral IPs occur in less than 5% of cases (8). Men are three to five times more commonly affected than women, and whites are more commonly affected than blacks (7,8,11,13). The typical age range is 40-60 years, although IPs in the nasal septum often occur at a younger age (iO,i4-16). The etiobogic characteristics of IPs are unknown, although an

cyst

inclusions

interspersed

throughout the epithelium and a high intracellular glycogen content (8,17). The IP gets its name because of its unusual growth pattern into the underlining stroma rather than in an exophytic direction. bPs have been cabled by many names, including endophytie papilboma (to suggest its growth pattern), squamous cell papibboma, transitional cell papibboma, cybindricab epithebioma, inverting papilboma, and sehneiderian papilboma. The terms used for the exophytic papilbomas are fungiform (most common) or cylindrical cell (rare) papilbomas (8,17). Fungiform papibbomas tend to occur on the nasal septum. Cybindricab cell papilbomas favor the maxillary sinus (8). Squamous cell carcinomas may be associated with bPs in 5.5%-27% of patients (7-11,18). Other neoplastic

forms, such as mucoepidermoid carcinoma, verrucous carcinoma, and adenoid cystic carcinomas, have also been reported to coexist with IP. Malignant change of an IP has a weak association with human papibbomavirus-16 (ii). Because of the association of IP and squamous cell carcinoma and the very high recurrence rate of IP (15%-78%) (7,8,10,11,15,18), complete surgical extirpation is the treatment of choice. This is usually accomplished by means of lateral rhinotomy and en bloc excision of the lateral nasal wall (7,15,19). Midfaciab degboving procedures may be an option that has improved cosmetic results; however, recurrence rates are still reported to be 22%-29%, even with lateral rhinotomy and midfaciab degboving (18). When the IP is far advanced and entering the intracranial space, craniofaciab resection may be required, with a combined neurosurgicabotorhinobaryngobogic team (18,19). The morbidity of craniofaciab resection must be weighed against the benefit of completely removing the besion. If an imaging modality could enable accurate prediction of the presence and location of a coexistent malignancy, surgical planning would be greatly aided. Unfortunately, we have found that the signal intensity characteristics and enhancement pattern of IP are identical to those reported with squamous cell carcinoma (1-3,19). We could not distinguish IP from olfactory neuroblastomas, mebanomas, or small cell carcinomas.

Nor

could

we

identify

the

IP with squamous cell carcinoma within it. Although calcification may occasionally be seen in IPs and would be a useful finding in an intranasab mass

(usually

limiting

the

diagnosis

to

an olfactory neurobbastoma and IP), in the one patient in whom this was present at CT, we were unable to identify

the

calcification

with

MR

im-

aging. (The presence of increased attenuation on CT scans may not be a result of dystrophic calcification but may be reactive change along residual ethmoid sinus septa.) Som et al (20) have previously reported that the pattern of bone destruction of IP may be identical to that of squamous cell carcinoma, particularly in the sphenoid and frontal sinuses and along the anterior cranial fossa. Bone destruction has been reported in up to 30% of IPs and is presumed to be due to pressure necrosis (7,20,21). The presence of bone destruction is better evaluated with CT than with MR imaging; in the region of the eribnform plate, where the 504

Radiology

#{149}

b.

a. Figure

4.

Olfactory

age (4,300/90)

neuroblastoma

a mass

with

woman.

(a) Axial

RARE

12-weighted

im-

signal intensity and what appear to be striations/septations within the left nasal cavity component. Obstructed secretions (S) have high signal intensity. (b) Axial MR image (750/26) shows heterogeneous enhancement of the neuroblastoma. In a blinded reading, two of the three neuroradiobogists thought that this image showed

shows

in a 66-year-old

heterogeneous

IP.

a.

b.

Figure 5. Small cell carcinoma weighted MR image (3,500/90) with moderate heterogeneity

the right

side more

than

of the reveals of signal

nasal cavity in a 72-year-old a low-signal-intensity mass intensity. The mass expands

the left. (b) Fat-suppressed

administration of contrast material reveals enhancement as well as extension through tensity of this mass and the enhancement two cannot be distinguished.

bone is sievelike, tumor intracraniably with only seous

can extend minimal os-

of IP from inflambe more successful in routine cases in which the inflamed mucosa has low signal intensity on Ti-weighted images and very high signal intensity on T2weighted images. The signal intensity of IPs was never as high as that of benign inflamed mucosa or obstructed secretions. Nonetheless, it has been shown that hyperproteinaceous sinonasal secretions may have a variable signal intensity that may overlap the intensity pattern of bPs (22). The solid enhancing pattern of the IP may distinguish it from inflamed mucosa and/or mucoceles, which have peripheral rim enhancement (3). Minor salivary gland tumors and sarcomas of the sinonasal cavity have been reported to have high and low matory

disease

may

MR image

(700/26)

that the carcinoma has a homogeneous the eribriform plate (arrowheads). characteristics are no different than

changes.

Differentiation

coronal

woman. (a) Axial 12within the nasal cavity, the lamina papyracea

obtained

on

after

pattern of The signal inthose of IP; the

signal intensity characteristics with long TR pulse sequences (2,23,24). The premise that a mass with bow signal intensity at T2-weighted imaging represents a poorly differentiated tumor (and, therefore, a poor prognosis) is fraught

with

exceptions,

just

as

high signal intensity on T2-weighted images is not always indicative of benign tumors or inflammatory lesions. Nonetheless, MR imaging is very useful in determining the location and extent of sinonasab neoplasms. In two eases, intracranial extent was not definitely suggested with CT. In one of these instances, the incorrect CT interpretation was a result of severe metal artifact from tooth amalgam. In the other case, infiltration was very subtle and was not visualized with CT because of its bower soft-tissue resobution. There is no signature pattern of MR signal intensity characteristics or enNovember

1992

hancement diagnosis

ate

suggestive of IP. One

between

squamous with IP.

of a specific cannot differenti-

patients

with

cell carcinoma

coexistent

and

7.

8.

those

U

9.

verted papilloma of the nasal Otolaryngol 1980; 106:767-771.

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PM, Shapiro MD, Biller HF, Sasaki C, Lawson W. Sinonasal tumors and inflam-

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11.

Som

imaging

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and neck adenoid

carcinomas: a study with elinicopathological

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extension:

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yogI TJ, Dresel SHJ, Spath M, et al. Parotid gland: plain and gadolinium-enhaneed MR imaging. Radiology 1990; 177: 667-674.

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Friedburg H. methodological

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van Olphen AF, Lubsen H, van’t Verlaat An inverted papilloma with intracranial extension. J Laryngol Otol 1988; 102:

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Som P. Bernard papilloma: analysis 1989;

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Arch

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Som PM, Lawson W, Lidov MW. Simulated aggressive skull base erosion in response to benign sinonasal disease. Radiology 1991; 180:755-759. Weissler WW, Montgomery

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Myers EN, Fernau JL, Johnson JT, TabetJC, Barnes L. Management of inverted papilloma. Laryngoscope 1990; 100:481-490. Hyams DJ. Papillomas of the nasal cavity and paranasal sinuses. Ann Otob Rhinol Laryngol 1971; 80:192-206. KellyJH, Joseph M, Carroll E, et al. In-

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