Prenatal Sonographic Appearance of Congenital Fibrosarcoma 

Congenital infantile fibrosarcoma (CIFS) is a

relatively rare disease. Over the past 40

years, about 150 cases have been reported in the

literature. In 1951, Andersen1 reported 5 (3%) fibrosarcomas

in her series of 175 malignant tumors

in infants and children. Stout,2 reviewing

the literature on this subject in 1962, was able to

collect 42 cases of CIFS that developed in patients

5 years or younger, including 4 (10%) cases in

which CIFS was present at birth. In 1976, Chung

and Enzinger3 reported 53 cases of CIFS, of which

20 (38%) were present at birth. In 1991, Coffin

and Dehner4 reported 14 (2%) cases of CIFS

among more than 900 soft tissue tumors in children

and adolescents. Coffin et al5 later reported

a series of 26 cases, of which 21 (81%) were considered

congenital.

The widespread use of sonography during pregnancy

has resulted in a few reports of prenatally

diagnosed CIFS. Dolkart et al6 reported the prenatal

sonographic diagnosis of CIFS involving the

mediastinum. Recently, Michigami et al7 reported

on a fetus in which prenatal sonography

showed a huge hypervascular tumor of the fetal

neck, later proven to be CIFS. We report the prenatal

sonographic observation of CIFS in a fetal

extremity and discuss the differential diagnosis.

CASE REPORT

A 22-year-old woman, gravida 1 para 0, who had

received standard prenatal care was referred to

our unit for routine ultrasound examination in

her 22nd week of pregnancy. An ultrasound examination

at 14 weeks had been unremarkable.

The examination at 22 weeks revealed localized

swelling of the fetus’s left thigh (Figure 1A). Further

detailed examination revealed a soft tissue

growth extending from the greater trochanter to

the lateral epicondyle of the femur, with a maximal

width 3 times that of the opposite leg (Figure

1B). The femoral shaft of the abnormal leg was

slightly more hyperechoic than was that of the

unaffected leg. The mass was covered by redundant

skin. Color Doppler flow mapping revealed

normal blood flow in both legs. Targeted organ

screening revealed no other fetal anomalies.

The parents elected to terminate the pregnancy,

and following oxytocin induction, a male fetus weighing 435 g was aborted. On the lateral

aspect of the left leg was a 7-cm, poorly circumscribed

mass (Figure 2) with a pale gray and pink

cut surface. Light microscopy (Figure 3) revealed

small, solidly packed, spindle-shaped cells that

were separated by variable amounts of interstitial

collagen. Ultrastructural examination by

electron microscopy revealed fibroblast-like cells

with large irregular nuclei, 1 or 2 nucleoli, free

ribosomes, a well-developed Golgi complex, and a

prominent and often dilated endoplasmic reticulum.

The extracellular space contained scattered

collagen fibers and abundant electron-dense material.

The pathologic diagnosis was congenital fibrosarcoma

DISCUSSION

Swelling in a fetal limb may be due to any of a

number of conditions, including Klippel-Tre´naunay-

Weber syndrome, lymphangioma, lymphedema, or CIFS. In Klippel-Tre´naunay-Weber syndrome,

also called asymmetric limb hypertrophy, the major

abnormality is congenital or early childhood

hypertrophy of usually 1, but occasionally more

than 1, limb. The hypertrophy may coincide with

an area of hemangiomatous involvement.8,9 This

syndrome could not have accounted for the findings

in our case because the swelling in asymmetric

limb hypertrophy involves the entire limb.

Lymphangiomas, which are benign tumors of

lymphatic origin, are malformations consisting of

dilated lymph channels of various sizes lined by

endothelium. Generally, these tumors consist of

fluid-filled vesicles or cysts of various sizes.

Lymphangioma has been diagnosed in utero,10

but the characteristic appearance of hypoechoic

fluid-filled areas in lymphangioma could not be

confused with the sonographic findings in our

case.

Congenital lymphedema occurs in 2 forms: primary

lymphedema and the hereditary form,

called Milroy’s disease. The edema is confined to

the lower extremities and is firm and easily pitted.

The overlying skin is warmer than usual.

Lymphedema of the legs also occurs in Turner’s

(XO) syndrome. Infants with congenital lymphedema

may develop chylothorax and chylous ascites,

which may be seen on prenatal sonography.

In contrast to our case, in congenital lymphedema

both extremities are affected equally.

We could find no reference in the medical literature

(English and other common languages) to

CIFS in a limb being diagnosed prenatally. Puzey

et al reported a case of perinatal death caused by

shoulder dystocia with tumor rupture and massive

hemorrhage upon delivery; the tumor was

subsequently diagnosed as CIFS.11 Dolkart et al6

reported on the prenatal sonographic observation

of CIFS involving the mediastinum; sonography

demonstrated a homogeneous, echogenic mass

posterior to the sternum. Recently, Michigami et

al7 reported on a fetus with CIFS, which on prenatal

sonography presented as a huge hypervascular

tumor on the fetal neck. Because other cases

of CIFS involving an extremity have been diagnosed

after birth, our intrauterine sonographic

observation of CIFS involving a fetal extremity is

of special interest. In contrast to the findings in

postnatally diagnosed cases, we observed a soft

tissue growth covered by redundant skin on prenatal

sonograms.

The principal manifestation of CIFS is a nontender

or painless swelling or mass that can

range in size from 1 to 20 cm. The most common

sites of the masses are the extremities, especially

the foot, ankle, lower leg, hand, wrist, and forearm.

2,3 Roentgenographic examination may

show, in addition to the soft tissue mass, cortical

thickening and curvature of the bones.

Fibrosarcoma in newborns, infants, and young

children differs little histologically from that occurring

in adults but must be considered as a

separate entity owing to its more aggressive clinical

behavior. CIFS must also be distinguished

from the richly cellular, but benign, forms of fibromatosis

and especially from other types of

childhood sarcoma, such as embryonal rhabdomyosarcoma,

which behave more aggressively.

The microscopic picture of CIFS may be confused

with that of other mesenchymal neoplasms,

but in most cases the uniformity of the spindleshaped

tumor cells, the solid growth pattern, and

the fascicular arrangement permit a reliable diagnosis.

In cases of doubt, reticulin preparations

should be obtained to demonstrate the capacity of

the tumor cells to produce collagen.12

Despite rapid growth and a high degree of cellularity,

most CIFSs are cured by wide local excision

or by amputation (if the large size of the tumor

leaves no alternative).13 In the case we

describe, following extensive discussion, the parents

requested termination of the pregnancy

based on the sonographically detected abnormalities.

To our knowledge, this is the first published

report of the intrauterine sonographic observation

of CIFS involving an extremity. We suggest

that the possibility of fibrosarcoma be considered

in the differential diagnosis of any soft tissue

mass noted during fetal sonography.

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