From the Archives 0 f the AFIP James

Primary Richard Frederick

Ewing

L. Rosado L. Bloem,

Ewing

de Christenson, MD #{149} Margaret

sarcoma

typically lated

328

Ewing we

fected

sarcoma

rib

was

collected

(9%)

and The

contour

even

change

al hemithorax

rib

was

varied

volvement

predominantly

affected from

accompanied

describe

the

spectrum

augmented

mild.

subtle, by

in

isolated

rib

of primary

also

affected

ipsilaterrib

hemithorax.

Ewing

accompanying

af-

although

to solitary

of the

Se-

lytic-

were

of cases,

involvement

findings by

mixed

of the

opacification

appropriate

this

the

patterns

35%

Abnormalities

complete

of radiologic

where

(9%)

“expanded”

corre-

From

but

ar-

Our

Radiographically, cases,

sclerotic

was

usually

(82%)

years.

#{149}

#{149}

that

years.

radiologically 40

in ribs.

MD

tumor

10-25

and

USAR

MC,

Kumar,

bone

aged over

arising in most

.

malignant

adults

in consultation lytic

USNR

Lt Col,

#{149} Rajendra

proved

( 1 0%)

predominantly

encountered.

young

of histologically

34 lesions

identified

sclerotic

rib,

cases

Davis, MD KransdorJ

highly

and

MC,

of Rib1

common,

in adolescents

contain

LCDR,

Maf, MC, USAF A. Stull, MD

is a relatively

occurs

chives

the

Sarcoma

P. Moser, Jr. Col, MC, USA2 #{149} Michaelj W. Gilkey, Lt Col, MC, USAF #{149} MarkJ.

Melissa Joban

ries,

L. Buck,

sarcoma

pathologic

inWe of

material.

U INTRODUCTION Several years ago, we encountered in consultation a 7-year-old boy with malaise, anorexia, low-grade fever, and intermittent, nonproductive cough. The chest radiograph obtained at presentation revealed nearly complete opacification of the right hemithorax due to a large soft-tissue mass, accompanying pleural effusion, and right lung atelectasis. A biopsy specimen of the mass was initially interpreted as “soft-tissue”

Ewing

sarcoma.

The preoperative right fifth posterior mediately appreciated,

Index

terms:

Ewing

sarcoma,

1990;

10:899-9

RadloGraphics I

From

the

Department

pedic

Pathology

6825

16th

veston.

chest radiograph also revealed “an unusual rarefaction” of the rib. The significance of the skeletal abnormality was not imand the abnormal rib was initially ignored. Surgical inter-

and

Washington,

(R.K.);

Department

1 #{149} Ribs,

neoplasms.

Civic

Hospital,

Ottawa

Radiologic DC

Pathology

20306.6000;

RadioIog’,

of Radiology’, Georgetown University Medicine, Uniformed Sert’ices University

edjune

13,

The cial

1990.

address: opinions

or as reflecting

‘RSNA,

Address

reprint

Department or assertions the

views

requests

of Radiology. contained

herein

of the

Department

Ottawa,

(R.P.M.,

M.J.K.,

Department

of Diagnostic

partment Nuclear 2 Current

47 1 .3281

14

ofRadiology,

(F.W.G.)

St. NW,

Tex

47 1 . 328

Hospital, ofthe

Ontario,

of Radiology, University

Canada

M.L.R.C.), Hospital

(M.J.D.);

Armed University

Institute

ofTexas

at Leiden,

Washington. DC (M.A.S.); Health Sciences, Bethesda,

Departments

Forces The

and Md

Medical Netherlands

Department (M.J.K.).

of Ortho. of Pathology. Branch,

Gal.

(J.L.B.);

Dc.

of Radiology and Received and accept.

to M.J.K. Penn are

State the of the

University. private Army

views or the

Milton of the Department

S. Hershey authors

Medical and

are

Center. not

Hershey.

to be construed

Penn. as offi.

of Defense.

1990

899

vention via night-sided in tumor “debulking,” by radiation therapy

proxfmatcly

thoracotomy resulted which was followed and chemotherapy. Ap-

6 months

elapsed

before

a night

fifth nib resection was performed. Unfortunately, less than 1 year later, a mass recurred in the night side of the lower chest, with accompanying ipsilateral hilar nodal metastases.

In retrospect, we believe this was a case primary Ewing sarcoma of rib, wherein at presentation the huge soft-tissue mass ob-

of

scuned the relatively subtle osseous origin (from nib) of the tumor. This interesting case has subsequently stimulated an examination of similar cases in our archives and a review of the literature. The purpose of this report is to facilitate

entity

the

correct

diagnosis

by familiarizing

ed in diseases

affecting

ly of adolescents spectrum mary U

CLINICAL

An

and

young

estimated

adults)

the

of nib.

CHARACTERISTICS are Ewing 50%-60% the

40%

with

of pni-

1 0% of all primary

especially

interest-

(particular.

appearances

sarcoma

bone tumors proximately while

the chest

of radiologic Ewing

of this

all physicians

femur,

.

tibia,

of Ewing

malignant

sarcomas (1 ,2) Aparise in long bones, and

sarcomas

Figure 1. Distribution of 34 cases of Ewing sancoma of rib from the archives of the Department of Radiologic Pathology, Armed Forces Institute of Pathology, Washington, DC. Large numbers represent numbers of cases.

humerus,

occur

in flat

bones, most commonly the innominate bone, nibs, and scapula (1 ,2) Scattered reports in the literature, however, describe the origin of Ewing sarcoma in nearly every bone in the skeleton (1 -4) According to a review of a combined total of 87 1 cases of Ewing sancoma, Mirra (1) described the following most commonly affected sites, in decreasing order

ment account for only 6% and 2%, nespectively, of Ewing sarcoma of long bones) In addition, it is generally accepted that ing sarcoma can occasionally arise in an traosscous location, so-called soft-tissue ing sarcoma (5,6). The typical patient with Ewing sarcoma,

offncquency:

of 10 and 25 years (1). In our series of 34 patients with Ewing sarcoma of rib, the age at presentation averaged 12.4 years (range, 3 years) Eleven patients presented by age 1 0 years, while 26 patients

.

.

(14%),

(8%), long tomic

tibia

and

femur

(25%),

pelvis-ilium

(1 1%),

humerus

(10%),

ribs

(6%).

In Ewing

lowed taphysis

by the

middiaphysis

(1 5%)

confined to the (ic, metaepiphyseal

(1)

end

.

Primary

fibula

sarcoma

bone, the most commonly region is the metadiaphysis

of

affected (44%),

(33%) Ewing

of a long bone and epiphyseal

notwithstanding between

and

anafol-

me-

the

site

of origin,

presents

the ages

. 5-28

.

sarcoma

presented male ratio

by age 20 years. The male-to-fewas 2 : 1 for patients with primary

is unusual involve-

Ewing sarcoma dominance has

of rib. A similar been reported

Ewing

occurring

sarcoma

male prepreviously

elsewhere

U

Ra4ioGrapbics

U

Moser

et a!

Volume

for

in the

skeleton. In our series, anatomic location failed to demonstrate a predilection for then right on left hemithoracic involvement on for involvement of a specific rib(s) (Fig 1).

900

(1). EwcxEw-

10

ci-

Number

5

As

with

most

bone

tumors,

regardless

of

Extensive peniosteal reaction is not tune of primary Ewing sarcoma of rib, though a diverse spectrum of peniosteal

type, the symptoms of patients with primary Ewing sarcoma of rib are also disappointingly nonspecific (1 ,2 ,7). Most complain of pain, occasionally accompanied by swelling at the affected site. Among our 34 patients

with

tions

sarcoma of rib, the most common complaint was pain, recorded in 16 cases. In three of these, pain was associated with mild palpable

Thirteen

patients

soft-tissue

presented

mass,

with

usually

sociated pain. These symptoms of relatively short duration (ic, to months) Infrequent presenting included fever (n 2), cough sis (n = 1), and anorexia (n tients presented with a pathologic through

the affected

a

without

as-

were usually several weeks symptoms

.

(n i).

2) , ptoTwo

be

encountered

in Ewing

sarcoma,

particularly when the tumor arises in long bones (8, 1 6, 1 7) When noted, accompanying periosteal reaction is usually parallel to the shaft of the affected bone; terms such as ‘laminated, ‘lamellated, and ‘onion skin” have been used to describe its appearance. There may be coexistent, more aggressive periosteal reactions oriented (approxi.

Ewing

trauma.

can

a feaalneac-

pa-

fracture

rib.

‘

‘ ‘

‘

‘ ‘

mately)

perpendicular

affected

bone,

‘

to the

for which

long

terms

axis

such

of the

as “spi-

culated,” “Codman tunately, does not

“hair on end,” “sunburst,” and triangles” have been used. Unforthe pattern of peniosteal reaction establish a specific histologic diagnosis (1 8) To the contrary, the pattern of peniosteal reaction merely reflects the biologic activity of the underlying disease. Therefore, the more aggressive the appear.

RADIOLOGIC FEATURES The radiologic features of Ewing sarcoma have been well described when the lesion occurs in long bones (1 ,2,8-iO) (ie, femur, U

ance

tibia, on humerus), wherein Ewing sarcoma usually causes a “moth-eaten” on permeative pattern of lytic bone destruction. The length of the radiographic abnormality is usually 81 0 cm on greaten. The extent of both intraosseous and adjacent soft-tissue involvement may be underestimated, especially if scintig-

of the peniosteal

spiculated

periosteal triangles) , the

man ity

of the

is not

lesion.

diagnostic

reaction

(ic,

reaction, greater the

Even

this

latter

of a neoplasm,

divergent,

multiple biologic appearance however,

cause it can be encountered with other conditions, such teomyclitis.

Codactiv-

in association as aggressive

be-

os-

raphy or computer-assisted imaging (ic, computed tomography [CT] or magnetic nesonance [MR] imaging) is not used (i 1 -14). The lesion typically occurs in the middiaphysis or metadiaphyseal portion of the affected bone (1) Less common radiologic .

patterns include mixed volvemcnt or a lengthy at the affected site (15).

September

1990

lytic-blastic

area

bone

in-

of osteosclerosis

Moser

et al

U

Ra4ioGrapbks

U

901

a.

b.

d.

C.

Figure 2. Case 1. Ewing sarcoma of left second rib. Posteroanterior (a) and lateral (b) chest radiographs show a large, round opacity in the left upper chest arising from the anterior aspect of the left second rib. Axial CT scans (c, d) demonstrate the origin of the lesion (from the rib) and delineate extensive intrathoracic

902

U

and,

RadioGrapbks

to a lesser

extent,

U

Moser

extrathoracic

et a!

involvement.

Volume

10

Number

5

A striking accompanying feature of primaEwing sarcoma of nib is the associated softtissue mass, observed in 32 of 34 cases in our series (Figs 2-4) In only two of our patients with primary Ewing sarcoma of nib was the 17

.

tumor tation. tissue

confined to the rib at clinical Furthermore, the accompanying mass

was

large

compared

seous

involvement

typically

with

presensoft-

disproportionately

the extent (within

the

of intraosnib of origin).

Figure 3. Case L The extent of the lesion shown in Figure 2 is clearly demarcated on axial Ti -weighted (repetition time msec/echo time msec = 550/30) (a) and T2-weighted (2,000/50)

(b) images 80)

and

MR image

on a coronal

Ti-weighted

(5 50/

(c).

C-

September

1990

Moser

et

a!

U

RadioGrapbks

U

903

b.

a. 4. Case 2. rib in a 1 0-year-old

Ewing sarcoma of right third boy. Posteroantenior (a) and

Figure lateral

(b)

chest

reveal

radiognaphs

a huge soft-tis-

sue mass in the right upper chest, causing leftward displacement of the heart and mediastinum. The mass arises from the right third rib, which demonstrates ill-defined lysis and expansion of its anterior aspect. CT scan (C) shows both anterior rib

destruction

has both thoracic

and

large

soft-tissue

massive intrathoracic components.

mass,

and

minimal

which extra-

-

tL C.

I,

a.

b.

Figure

5. Case

3.

Ewing

(a) and corresponding sion

904

U

of the

Ra4ioGrapbks

right

sarcoma

collimated

third

U

rib,

with

Moser

of right

view a large

et al

(b)

third

rib

in a 6-year-old

demonstrate

associated

soft-tissue

a long

girl.

moth-eaten

Posteroanterior

chest

or permeative

radiograph

destructive

le-

mass.

Volume

10

Number

5

Figure

ond

6. Case

4.

Ewing

rib in an i i -year-old

anterior

chest

radiograph

sarcoma of right 5ccboy. Collimated postero(a) reveals an ill-dc-

fined lytic lesion of the anterior right second rib with associated soft-tissue mass. Increased radionuclide activity is noted in the affected rib on

CT scan (c) demonstrates

scintigram

(b).

volvement

and coexistent

mass

is clearly

demarcated

soft-tissue on coronal

(499/28) (d). Corresponding gross (e) clearly demonstrates the mass.

In our

series,

approximately

the soft-tissue 1 1 cm

mass

in diameter.

component

averaged The

bon-

dens of the mass were either smooth on lobulated, and the mass was frequently inhomogencous

on

CT scans

on MR images, probably reflecting tumor necrosis (Figs 5 , 6) In all cases in which Ewing sarcoma of nib had an .

associated

September

soft-tissue

1990

mass,

was

larger

than

the

rib in-

mass.

The

MR image

photograph

extrathoracic

component. The extraosscous component tended to “engulf’ the rib in a relatively symmetric fashion, but the was occasionally eccentric

soft-tissue growth or asymmetrically

exophytic.

the intrathoracic

Moser

et a!

U

RadioGrapbics

U

905

a.

d.

C.

Figure

7. Case 5. in a 17-year-old

Ewing

rib

male.

sarcoma Posteroanterior

limated

posteroanterior (b), radiographs reveal an opacity tenor chest. On images, differential

the

of right

and lateral in the right

basis of findings considerations

third (a),

from include

(C)

col-

chest midanthese both

pneumonia (especially on the posteroanterior view) and pleural-based mass (especially on the lateral view) Anteroposterior tomogram (d) shows moth-eaten/permeative destruction of the anterior third rib, which is also minimally cxpanded. Expansion of rib and associated soft-tissue mass are readily apparent on CT scan (e). .

C-

906

U

Ra4ioGrapbics

U

Moser

Ct al

Volume

10

Number

5

a.

b.

8. Case 6. Ewing sarcoma of right first rib in a 23-year-old man. Posteroanterior (a) and collimated view (b) of the apex of the right hemithorax demonstrate ill-defined right first rib complicated by pathologic fracture (arrow in b) Note accompanying right which could be confused with Pancoast tumor. Figure

.

Ewing hemithorax. bitrani!y posterior,

sarcoma can affect any rib in either In this series, we somewhat andivided the rib into three segments: lateral (on middle) , and anterior.

The lateral portion of the rib was affected most commonly (n = 16), with near-equal involvement of the anterior (n 8) and postenor (n = 1 0) segments. Thirty-five percent of the affected ribs had an “expanded” contour, in which case it was either the lateral or anterior aspect of the rib that was affected (Fig 7) In all cases in which this feature was .

noted,

however,

The typical ma exhibits

ance

September

on radiographs,

1990

the expansion

rib affected a predominantly

with

as seen

was

ly 80%

of our

cases,

while

the

chest

radiograph

destruction apical

of the

mass,

remaining

nibs

had either a mixed lytic-sclerotic or predominantly sclerotic pattern (Figs 8- 1 0) These features are best appreciated on plain radiographs but are confirmed with plain tomography or CT. The imaging workup of a patient afflicted with Ewing sarcoma of rib should commence with chest radiography. On the chest radiographs, the soft-tissue mass can obscure the underlying rib involvement, particularly if the tumor arises in the lateral aspect of the .

mild.

Ewing sarcolytic appear-

in approximate-

Moser

et a!

U

RadioGrapbics

U

907

a. Figure

b. 9- Case

7.

Ewing

sarcoma

of left

second (a) and lat-

rib in a 9-year-old girl. Posteroanterior eral (b) chest radiognaphs reveal marked opacification of the superior aspect of the left hemithorax due to a large soft-tissue mass. In this case, Ewing

sarcoma

arose

from

a sclerotic

left

second

rib, which is readily seen on collimated view Corresponding CT scan (d) shows tumor cornpletely opacifying the left apex.

908

U

RadioGrapbks

U

Moser

et a!

(C).

Volume

10

Number

5

I

.

C.

Figure

10.

Case

8

Ewing

sarcoma

of left

1 ith

rib

in a 22-year-old

man.

Antenoposterior tomognam (a) reveals a mixed lytic-blastic lesion of the left 1 ith rib. Posterior scintigram (b) shows increased radionuclide activity in the affected rib. Radiograph ofspecirnen (C) shows ill-defined bone destruction throughout the affected rib. Corresponding gross photograph (d)

shows

large

lin-eosin)

struction (arrowhead)

September

the

associated

nib of origin

(labeled mass (large

R

between

the

small

arrows) Macrosection (e) from a similar case shows a permeative pattern typical of Ewing sarcoma. Note areas of trabecular within rib and large associated soft-tissue mass

1990

soft-tissue

.

arrows) and (hematoxy-

of bone dereinforcement (arrows).

Moser

et a!

U

Ra4ioGrapbics

U

909

,.,.t

a

b.

d.

C.

C-

Figure

11. Case

9-

Ewing

sarcoma

enth rib. Posteroanterior chest shows a pleural-based opacity the left hemithorax. The lesion seventh rib, which demonstrates

eaten

or permeative

destruction,

of left sev-

radiograph in the lower arises from extensive

most

(a) part of the left moth-

readily

ap-

preciated on the oblique radiograph (b). Scintigram (C) shows increased activity in the affected rib. Associated intrathoracic mass is readily appreciated on CT scan (d). Axial MR images (e, 2,000/50; f, 2,000/100) show lesion originating from rib and extrathoracic soft-tissue involvement, which was not appreciated on the CT scan.

affected rib. In such cases, oblique radiographs might be necessary to delineate the osseous involvement. If bone scintignaphy performed (as occurred in nine of our 34 cases) , the affected rib demonstrates increased radionuclide activity (Figs 6, 10, 11). Angiognaphy

logic coma

910

U

is unnecessary

assessment of most of nib. If obtained,

RadioGrapbics

U

in the

radio-

cases of Ewing the angiogram

Moser

et al

san-

is

shows minimal neovasculanity, perhaps with vascular displacement by the accompanying soft-tissue mass (Fig 1 2) CT or MR imaging .

is invaluable

in demonstrating

the

origin

of

the tumor from rib, the extent of both intnaosseous and extnaosseous involvement, and the relationship of the tumor to adjacent structures. These determinations allow physicians to optimize the surgical treatment of the patient (1 1 -14).

Volume

10

Number

5

Figure

12. Case

graph nia

(a) shows

and

of large

coexistent

soft-tissue

10.

Ewing

sarcoma

marked opacification right-sided pleural

mass

and small

of right

1 0th rib of inferior right effusion. Actually,

right-sided

pleural

in a 5-year-old boy. Posteroanterior chest radiohemithorax, mimicking right lower lobe pneumothe right basal opacity was due to a combination

effusion

Representative view from the anteropostenior angiographic right i 0th rib and moderate leftward displacement of the tissue mass. Minimal neovasculanity is noted in the vicinity

U

PAThOLOGIC

CHARACTERISTICS

Ewing sarcoma is the prototypical “small blue cell” or “round cell” tumor (1) The blueness is attributed to the fact that the majonity of the tumor is composed of nuclei, which stain blue with hematoxy!in. The small, round cells have a small amount of indistinct (pale, grainy, or stringy) cytoplasm (Fig 1 3a, 1 3b); ccl! membranes are also indistinct. The nuclei are usually round to oval, with minima! irregularity. In some cases (so-called large ccl! or atypical Ewing sarcoma) , the cells have large or cleaved nudci (19,20). There is often one inconspicuous nucleolus. The cells are arranged in sheets or broad bands separated by fibrous septa, and there is often extensive necrosis. .

Mitotic

figures

are frequently

seen

(Fig

1 3b,

1 3c) No significant histologic differences are noted between primary Ewing sarcoma of nib and Ewing sarcoma arising elsewhere in the skeleton. In most histologic sections of Ewing sarcoma, g!ycogcn is demonstrable in the cells with periodic acid-Schiff staining (Fig 1 3d); .

September

1990

caused

study abdominal of the

confirmation of periodic

by Ewing

demonstrates aorta by the destroyed rib.

of right

In the

frequently entiation

performed of Ewing

past,

after

reticulin

staining

was

to assist in the differsarcoma from malignant

it showed

Ewing

soft-

the removal material by

a delicate

but

sive network in lymphoma but Ewing sarcoma. Immunohistochemical ing is now the preferred method guishing

1 0th rib.

lysis of the posterior large accompanying

is established acid-Schiff-positive

amylase.

lymphoma;

sarcoma

(b)

sarcoma

from

very for other

exten-

little

in staindistin-

round

cell tumors. Ewing sarcoma stains negatively for most of the following markers: leukocyte common antigen (which is positive in lymphoma) , lysozome (which is positive in granulocytic sarcoma) , desmin and myoglobin (which are positive in rhabdomyosarcoma) , and neuroectodermal markers (which are positive in neuroblastoma or metastatic oat cell carcinoma) Ewing sarcoma stains positively for vimentin (a nonspecific mesenchymal marker) and occasionally neuron-specific enolase , which, unfortunate.

Moser

et a!

U

Ra4ioGrapbics

U

911

ly,

is a misnomer

specific.

lesions

ferential diagnosis chondrosarcoma coma. Oven the years,

Ewing

it is not

because

Other

neuron histologic dif-

in the

include and small

mesenchymal cell osteosar-

the histogenesis

(pheno-

of the malignant cells) of Ewing sancoma has been extensively debated. Unfortunately, most routine studies, including immunostaining and electron microscopy, demonstrate no specific differentiation in the cells of Ewing sarcoma. More recently, diverse studies performed on cultured cells from Ewing sarcoma support neunoectodermal differentiation (20).

Enchondromas

destructive

because

was likely

age of the

34 patients

likely tional mors lung;

is via an extrinsic,

of remodeling on even Neither cosinophilic myclitis mass

seen

in

on

will as large

erosive

frank invasion. granuloma nor

be accompanied as that

process osteo-

is moth-eaten

then Ewing granuloma,

sarcoma of nib, cosinophilic and osteomyclitis can be indis-

tinguishable

radiologically.

performed volvement

and multiple arc detected,

nosis

912

U

is cosinophilic

RadioGraphics

sites of osseous the most likely granuloma.

U

Moser

et al

are

on radiographs

sarcoma

of rib.

produce

sarcoma

dysplasia of the

greaten

than

ofnib (27). The two

of Further-

a matrix

of rib.

frequently affected rib

that most

tumors

noted

that

in Ewing

common

and

rib

uncommon

is a very

Ewing

Conversely,

expands the to an extent far

sarcoma

malignant

encountered

teosarcoma

mineralization

ivorylike, osteosarcoma

coexistent

or permeative,

If scintigraphy

in Ewing

fibrous contour

dengoes

in primary

Ewing sarcoma of rib. However, if the Ewing tumor is confined to rib (an uncommon cmcumstance encountered in only two of our 34 cases) and the radiologic pattern of bone destruction

dysplasia

primary

in children sarcoma site

are os-

(22,24) for

.

The

osteosar-

coma, although, theoretically, te!angicctatic osteosarcoma (which most commonly arises in the proximal humerus) could be mistaken for the moth-eaten or permeative variant of typical lytic Ewing sarcoma of rib (22). More commonly, however, osteosarcoma elaborates a matrix of malignant ostcoid that un-

by a soft-tissue

occurring

seen

Ewing

enchondromas

bone

to occur in olden adults. As an addidistinguishing feature, Pancoast tuarise in the (extraosscous) apex of the therefore, if nib is involved, the in-

volvement

with

.

1 2 .4 years, Ewing sarcoma of to be confused with neuno-

blastoma, which affects younger children, mctastases, lymphoma, mycloma, on Pancoast tumor, all of which are much more

its associated

confused

can subsequently mineralize in a charactenistic pattern of punctate, flocculcnt, on ringsand-arcs calcifications; none of these featunes is seen in Ewing sarcoma of rib (1 8) In addition, neither enchondroma nor fibrous dysplasia of rib has a large associated soft-tissue mass, whereas this feature is commonly

cosinophilic granu!oma, 1-26). This broad list than its length suggests, it can be narrowed readily of clinical on laboratory correlation. For example,

the average

our series rib is not

with

more,

(5,2

formidable

be

and fibrous

pattern

patients

eloma, neunoblastoma, osteosarcoma (both osteoblastic and the osteolytic or telangiectatic variant) , Pancoast tumor, pleural-based

however, because with a combination data and radiologic

might

tumors on tumorlike processes that commonly affect nibs (27); neither entity is likely to be confused with primary Ewing sarcoma of nib, however. Enchondromas grow in a lobular configuration, which is clearly distinguishable from the moth-eaten on permeative

U DifFERENTIAL DIAGNOSIS Differential diagnoses for Ewing sarcoma of rib include multiple entities of diverse causes, such as metastases, lymphoma, my-

is less

of nib and

mass

pneumonia or a pleural-based mass. Careful scrutiny of the radiograph will enable detection of coexistent intraosseous involvement of a solitary rib, a finding that excludes the possibility that the lesion originated as a pleural-based mass. If doubt persists, intnaosseous origin of the tumor can be confirmed with either CT on MR imaging.

type

masses, pneumonia, and osteomyclitis

sarcoma

soft-tissue

is

indiag-

in a so-called

or cloudlike pattern (1 8) is commonly complicated

soft-tissue

mass

.

solid, Because by a

at clinical

presen-

tation, a blastic ably be confused variant of Ewing

osteosarcoma could conccivwith the osteosclerotic sarcoma of nib. This form of

Ewing

of rib could

sarcoma

not be confused

with blastic metastases, however, as the latten are not associated with a soft-tissue mass. Most radiologic education is focused on a “pattern approach of instruction” : (a) necognition of the radiologic abnormality (on radiographs, plain tomograms, CT scans, MR images, sonograms, ctc) and (b) according

Volume

10

Number

5

a.

b.

13. Ewing sarcoma. (a) Low-power photomicrograph (original magnification, X75; hematoxylin[H-E] stain) shows periosteal new bone (arrows) trapped between sheets of small blue tumor cells. (b) High-power photomicrograph (original magnification, X300; H-E stain) shows many small undifferentiated cells that have minimal, indistinct cytoplasm. Note mitotic figures (arrows) (C) Oil-immersion photomicrograph (original magnification, X750; H-E stain) of a touch imprint preparation of Ewing sarcoma shows round, regular nuclei containing nucleoli (better seen here than in paraffin sections) , small amounts of cytoplasm, and a mitotic figure, complete with mitotic spindle. (d) High-power photomicrograph (original magnification, X300; periodic acid-Schiff stain) shows red glycogen granules in many of Figure

eosin

.

the

cells.

to the abnormal pattern discerned, provision of a reasonable differential diagnosis, with acknowledgment that relatively few diseases manifest a pathognomonic radiologic ap-

pearance.

In this

report,

we have

used,

in our

opinion, a better educational approach that begins with a specific disease and studies all of its radio!ogic manifestations. We have attempted to discuss, in some detail, the entity of Ewing sarcoma of rib and familiarize the reader with a!! of the radiologic manifestations of this disease. This approach should fa-

September

1990

cilitate

hope

earlier,

will

correct

result

and favorable afflicted with (28-33).

outcome primary

ACknowledgments: and Wendy script.

diagnosis,

in more

for

Moser

we

treatment

for those individuals Ewing sarcoma of rib

We thank

Baker

which

effective

preparation

et a!

Curt of the

U

Wolfgang manu-

Ra4ioGrapbics

U

913

i

.

Bone

tumors:

clinical,

radiologic,

and pathologic correlations. Philadelphia: Lea&Febiger, 1989; i087-1117. Wilner D. Radiology ofbone tumors and lied disorders. Philadelphia: Saunders,

2.

1982; 3.

Remus WR, Gilula LA, Nesbit M, et al. Radiology of Ewing’s sarcoma: Intergroup Ewing’s Sarcoma Study (lESS) . RadioGraphics 1984; 4:929-944. Moser RP, Madewell JE. An approach to primary bone tumors. Radiol Clin North Am 1987; 25:1049-1093.

17.

REFERENCES MirraJM.

U

al-

1 8.

Gilula LA, Shirley SK, Askin FB, Radiographic appearance of Ewof the hands and feet: report

19.

2462-2573.

Remus WR, Siegal GP. ing sarcoma

study of 20 cases of large-cell (atypical) Ewing’s sarcoma of bone. Am J Surg Pathol 1980; 4:29-36. Cavazzana AO, MiserJR, Jefferson J, Triche

from

4

the Intergroup Ewing Sarcoma Study. AJR 1985; i44:331-336. Strege DW, Hamel DP, Vogler C, Schajowicz F. Ewing sarcoma in a phalanx of an infant’s finger: a case report. J Bone Joint Surg [Am]

Mascimento AG, Unni K.K, Pritchard DJ, Cooper KL, Dahlin DC. A clinicopathologic

.

1989;

5.

1987;

G, Mendelson DS, Ambiner Ewing sarcoma with comcorrelation. Skeletal Ra-

diol 1983; 9:234-237. NP, Reiman HM, Pritchard FJ, Smithson WA. Extraosseous

a study

of 42 cases.

Dvorak sarcoma

Cancer

i989;

PF, Vorlicky LN, Nesbit ME. Ewing’s of rib, presenting as the superior

Sherman roentgen

Clin

Pediatr

10.

1 1.

1955; 37:529-539. EwingJ. The classic-diffuse endothelioma ofbone. Clin Orthop 1984; 185:2-5. Leffall LD. James Ewing, M.D.: contemporary oncologist exemplar. Arch Surg 1987; 122:1240-1243. Pettersson H, Gillespy T, Hamlin DJ, et al. Primary musculoskeletal tumors: examination with MR imaging compared with con-

13

modalities.

.

Boyko

OB, Cory

Mirkin

D, DeRota

and

JD, Sarrazin

1 6.

Ewing’s

148:317-322. Vanil D, Contesso

14.

.

24

.

25

.

DA, Cohen GP.

MD, Proviso

MR imaging

sarcoma.

27.

A,

28.

29.

of osteo-

30.

U

Moser

et a!

Radiol

1982;

WG. Ewing’s from four cases.

3 1.

sarcoma Clin Pc-

diatrRadiol 1977; 6:13-18. Kransdorf MJ, Moser RP, Gilkey 1W. Fibrous dysplasia. RadioGraphics 1990; 10:519-537. Bacci G, Toni A, Avella M, et a!. Long-term results in 1 44 localized Ewing’s sarcoma pa-

Thomas

PR, Foulkes

Primary

Ewing’s

wall

therapy.

MA, Gilula

sarcoma

the Intergroup

Cancer 1983; Rao BN, Hayes

Chest

to-

mography in the evaluation of 4 i cases of Ewing’s sarcoma. Skeletal Radiol 1982; 11:8-13. Shirley 5K, Gilula LA, Siegal GP, Foulkes MA, Kissane JM, Askin FB. Roentgenographic-pathologic correlation of diffuse sclerosis in Ewing sarcoma ofbone. Skeletal Radiol 1984; 13:69-78. Levine E, Levine C. Ewing tumor of rib: radiologic findings and computed tomography contribution. Skeletal Radiol 1983; 12:227233.

RadioGrapbics

J Belge

copathological aspects of 303 cases from the Intergroup Ewing’s Sarcoma Study. Hum Pathol 1983; 14:773-779. Franken EA, Smit JA, Smith WL. Tumors of the chest wall in infants and children. Pc-

Ewing’s

ribs:

a report

Sarcoma

Study.

51:1021-1027. FA, Thompson

resection

Can-

LA, et al.

of the

El, et al.

for Ewing’s

the rib: an unnecessary procedure. ThonacSurg 1988; 46:40-44. Pritchard DJ, Dahlin DC, Dauphine

sarcoma Ann

of

RT, Tay-

br WF, Beabout JN. Ewing’s sarcoma: a clinicopathological and statistical analysis of patients surviving five years or longer. J 32.

BoneJointSurg[Am] 1975; 57:10-16. Wilkins RM, Pritchard DJ, Burger EO, Unni ICK. Ewing’s sarcoma of bone: experience with 140 patients. Cancer 1986; 58:255 1-

2555. 33.

NeffJR. Orthop

U

findings.

diarn (Phila) 1970; 9:31-4 1. Kissane JM, Askin FB, Foulket M, Stratton LB, Shirley SF. Ewing’s sarcoma of bone: clini-

bone:

914

roentgen

Morgan 5K, Thurman in children, lessons

from

D, Piekarski

Computed

GH, Anderson LS, Bramson RT. wall tumors. Radiol Clin North Am

tients treated with combined cer 1989; 63:1477-1486.

AJR 1987;

G, Couanet

D, MasselotJ.

26.

1987;

164:237-241. Aisen AM, Mantel W, Braunstein EM, McMillin K!, Phillips WA, Kling TF. Mill and CT evaluation of primary bone and soft-tissue tumors. AJR 1986; 146:749-756.

genic

15

Radiology

127:507-518.

65:329-337.

RS, Soong KY. Ewing’s sarcoma: its classification and diagnosis. J Bone

ventional 1 2.

early

(Phila)

JointSurg[Arn]

9.

Omell Chest

1973; 11:197-214. Senac MO, Isaacs H, GwinnJL. Primary lesions of bone in the 1 st decade of life : retrospective survey of biopsy results. Radiology 1986; 160:491-495. Staalman CR. Ewing’s sarcoma in rib: a report on 7 cases with special emphasis to the

23.

mediastinal syndrome. 1971; 10:607-609.

8.

.

DJ, Frassica Ewing’s san-

64:i548-1553. 7.

21

22.

Rud

coma:

ii. Experimental evidence for a neural ongin of Ewing’s sarcoma of bone. Am J Pathol

71:i262-1265.

RoseJS, Hermann EP. Extraskeletal puted tomography

6.

20.

Nonmetastatic

the role 1986;

Ewing’s

of surgical

therapy.

sarcoma

of

Clin

204:111-118.

Volume

10

Number

5