1990, The British Journal of Radiology, 63, 456-460
Radiological features of extraskeletal Ewing sarcoma By Francis O'Keeffe, M D , James G. Lorigan, M D and Sidney Wallace, M D Department of Diagnostic Radiology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030, USA
(Received September 1989)
Abstract. The radiological features of extraskeletal Ewing sarcoma were reviewed in 22 patients whose average age was 22 years. Tumours were located in the extremities (11 patients), abdomen or pelvis (six patients) and the chest (five patients). The tumours ranged in size from 2 cm to 20 cm, were mainly well circumscribed and showed no evidence of calcification prior to treatment. Most tumours (13 out of 14) were of low attenuation or contained areas of lower attenuation than muscle on computed tomographic examination, and in six out of seven patients studied by ultrasound the tumours were hypoechoic or partly anechoic. No distinctive post-contrast medium enhancement pattern on CT examination (11 patients) or angiographic features (three patients) were evident. Tumour haemorrhage was a frequent microscopic finding and changes consistent with this were present in one patient on magnetic resonance imaging examination. Distant metastases or local recurrence developed in 13 patients with lung being the most frequent metastatic site (eight patients). Although its radiological features are non-specific, extraskeletal Ewing sarcoma should be included in the differential diagnosis of noncalcified soft-tissue tumours especially in a young age group and where located in an extremity or paravertebral region of the chest.
Extraskeletal Ewing sarcoma is a rare soft-tissue tumour which is histologically and ultrastructurally indistinguishable from the osseous form (Angervall & Enzinger, 1975), although it occurs in an older age group and has a predilection for different sites. The diagnosis is made on the basis of the histologic findings (Mahoney et al, 1978; Gillespie et al, 1979) in the absence of bone involvement. In many cases, the extraskeletal origin can be established radiologically although operative evaluation and microscopic examination may be required. It is important that this tumour be distinguished from other round cell tumours, for which specific treatment exists and whose biological behaviour is better known. Accordingly, we reviewed the radiological features in 22 patients.
specimens in six patients) and by radiological evaluation. This included conventional radiography in all 22 patients, computed tomography (CT) in 14, ultrasound in seven, angiography in three, and magnetic resonance imaging (MRI) (1.5T Signa Scanner, GE, Milwaukee, WI) in one patient. Three of the patients examined by CT had unenhanced studies only, and the remainder had both pre- and post-contrast medium examinations. Radionuclide studies with technetium methylene diphosphate ("Tcm MDP) were performed in 12 patients. Results Clinical data
The patients were identified through a search of the data base maintained by the Department of Patient Studies at M. D. Anderson Cancer Center having presented between 1975 and 1986. Histological criteria for diagnosis included the presence of sheets of round or ovoid cells separated by fibrous trabeculae with finely divided nuclear chromatin, a minute nucleolus and distinct nuclear membrane (Angervall & Enzinger, 1975). The presence of intracellular glycogen stores and other ultrastructural findings (Wigger et al, 1977; Mahoney et al, 1978; Gillespie et al, 1979) were used to distinguish it from other round cell tumours. Evidence for extraskeletal origin of tumour was provided by operative findings in 19 patients (including microscopic examination of resected adjacent bone
There were 13 male and 9 female patients in the study group. The age range was 4-52 years (average age, 22 years). Tumour locations were in an extremity (11 patients), abdomen or pelvis (six patients) and thorax (five patients). Of the 11 extremity lesions, seven were located in a lower and four in an upper limb. The abdominal and pelvic tumours were extraperitoneal, originating from the posterior pelvis (two patients), anterior abdominal wall (two patients), bladder dome and posterior subhepatic region (one patient each). All five chest tumours arose from the soft tissues of the chest wall: three were paravertebral and two axillary in location. Tumour size ranged from 2 cm to 20 cm. Thirteen patients presented with a palpable mass. Pain was reported in nine patients, pleuritic infiveand abdominal or pelvic in two patients each. One patient presented with a painful rapidly enlarging abdominal wall mass due to spontaneous tumour haemorrhage.
Address correspondence to F. O'Keeffe, MD, Department of Paediatric Radiology, The University of Texas Medical Branch, Child Health Center, Galveston, Texas 77550, USA and reprint requests to Sidney Wallace, MD.
Soft-tissue mass The tumour was well circumscribed in 16 patients as seen on either ultrasound or CT examination and in one patient on MRI examination. In eight of these patients a
Materials and methods
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The British Journal of Radiology, June 1990
Extra skeletal Ewing sarcoma
(a) (b) Figure 1. An 18-year-old female patient with right chest mass, (a) Non-contrast medium enhanced CT shows a large mass predominantly of low attenuation. A chest tube has been inserted for pleural effusion drainage and a hydropneumothorax is present, (b) On this post-contrast medium CT tumour enhancement is evident. At surgery, diaphragmatic pleural involvement was present.
pseudofibrous capsule was present at pathological inspection. Conventional radiographs were of limited value in defining these tumours, and revealed no abnormality in three patients with small lesions in an extremity. Chest lesions were masked on the chest radio-
graph in three patients by the presence of a pleural effusion. Despite the tumour being apparently well circumscribed in two patients with chest lesions, microscopic involvement of the lung was present. Prior to treatment there was no radiological evidence of tumour
Figure 2. A 12-year-old boy with extraperitoneal subfascial mass arising from the lower abdominal wall, (a) On postcontrast medium CT the mass is of lower attenuation than muscle and relatively well circumscribed, (b) Selective inferior epigastric angiogram shows a relatively hypovascular mass. The tumour also received blood supply from the superficial circumflex iliac artery (not shown). Vol. 63, No. 750
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F. O'Keeffe, J. G. Lorigan and S. Wallace
Figure 3. A 21-year-old man with tumour haemorrhage, (a) Sagittal T, weighted spin-echo image, 600/20 shows large mass with hyperintense areas, (b) On axial T2 weighted spin-echo image, 2000/80, hyperintense signal persists (arrow) consistent with subacute haemorrhage.
calcification, although in two patients, who were receiving chemotherapy prior to resection, small areas of amorphous calcification developed. Tumours were of low attenuation or contained areas of low attenuation (Fig. 1) with respect to muscle in 13 of 14 patients on unenhanced CT examination. The sonographic features in seven patients were mainly those of either a hypoechoic (four patients) or a partly anechoic mass (two patients). In the other patient studied, the tumour had a mixed echo pattern. 458
Figure 4. An 18-year-old female patient with left calf tumour, (a) Conventional radiograph shows periosteal reaction (arrows) in the adjacent tibia, (b) Pre- and post-contrast medium CT scans show tumour rim enhancement. At surgery, a fibrous pseudocapsule was present. The tumour did not invade the periosteum.
Tumour vascularity was variable as evident from angiography and contrast medium enhanced CT examinations. Angiography demonstrated moderately hypervascular tumours in two patients and a hypovascular tumour in one patient (Fig. 2). Early draining veins were The British Journal of Radiology, June 1990
Extra skeletal Ewing sarcoma
parietal lobe metastasis 5 years after initial diagnosis and marked post-contrast medium enhancement of a brain metastasis in another patient. Histological and ultrastructural analysis of the lesions was consistent with extraosseous Ewing tumour. Cystic intraperitoneal metastases developed in one patient (Fig. 5).
Figure 5. Intraperitoneal metastases from pelvic tumour. Contrast medium enhanced CT shows omental lesions (arrows). The larger lesion has a mural nodule.
not seen. Tumour enhancement was shown in four out of 11 patients who had contrast medium enhanced scans. Areas of haemorrhage within the tumour were evident at microscopy in seven patients and in one of these MRI (Fig. 3) revealed areas of high signal intensity on both T, and T2 weighted images in a predominantly low signal mass consistent with subacute haemorrhage. Spontaneous bleeding around the tumour occurred in one patient who presented with a rectus sheath haematoma and this was evident as a hypoechoic mass on ultrasound. Adjacent bone changes
One patient had a bone abnormality felt to be a reactive change to the adjacent soft-tissue mass. Periosteal reaction was present on a conventional radiograph (Fig. 4) with corresponding increased radionuclide uptake at the site of periosteal reaction. At surgery the tumour had a fibrous pseudocapsule and was adjacent to but did not involve the periosteum. Twelve patients had radionuclide studies with technetium methylene diphosphate ("Tcm MDP) and only one (described above) had abnormal radionuclide uptake. Recurrent and metastatic disease
Distant metastases (10 patients) or local recurrence (six patients) developed in 13 patients. Five patients had distant metastases at presentation. The time interval for local recurrence was between 3 months and 2 years. Eleven patients died between 6 months and 10 years after presentation and 11 are alive between 2 and 10 years after presentation, nine without measurable disease. The most frequent metastatic site was lung (eight patients) followed by liver and brain (three patients each). Of particular interest was the clinical presentation in one patient with spontaneous haemorrhage from a Vol. 63, No. 750
Discussion Although Tefft et al (1969) reported four cases of paravertebral round cell tumours of the chest closely resembling Ewing sarcoma of bone morphologically, the pathological features of extraskeletal Ewing sarcoma were first described in 1975 (Angervall et al). In that series of 35 patients, the tumours were frequently located in the soft tissues of the extremities or paravertebral region of the chest, although they have been described in almost all sites where other sarcomas are found. Unlike the osseous form there is no apparent sex predilection, patients are older with a median age of about 20 years and the trunk is a common site of occurrence. Occurrence before five years is unusual (Soule et al, 1978). Patients with extremity lesions usually present with a painless mass, but tumours arising elsewhere may be painful. All of our patients with chest lesions presented with pleuritic pain. Unusually the patient may present with a painful and rapidly enlarging mass due to spontaneous haemorrhage. Distant metastases, most frequently to the lung, are not uncommon at presentation. There may be no findings on conventional radiographs. When present, they are usually of a non-specific mass which can vary widely in size. Tumour calcification was not present in our series and to date has not been reported in the untreated patient. When adjacent bone changes are present, histological examination is necessary to separate it from the osseous form. The osseous form should show involvement of the marrow cavity by CT (Rose et al, 1983) or MRI. Angervall et al (1975) suggested that the rare and late occurrence of osseous involvement made it unlikely that this entity was just an initial soft-tissue manifestation of a skeletal Ewing sarcoma. The gross specimen often has a pseudocapsule and accordingly appears well circumscribed on CT, ultrasound or MRI examination. However, the tumour may be poorly circumscribed histologically (Meister & Gokel, 1978). Extraskeletal Ewing sarcoma is most frequently hypoechoic on ultrasound scans and on CT scans of low attenuation. These are non-specific findings seen with most soft-tissue sarcomas (Golding & Husband, 1982) and reflect the frequent microscopic findings of necrosis sometimes with cyst formation (Angervall et al, 1975; Wigger et al, 1977). Spontaneous tumour haemorrhage may alter the appearances with any of these imaging modalities or, as in two of our patients, may be the presenting feature. The angiographic appearances of this tumour are not distinctive and, although we studied only a small number of patients, it is not universally hypervascular 459
F. O'Keeffe, J. G. Lorigan and S. Wallace
unlike other soft-tissue tumours such as haemangioperi- mass, especially in an extremity or paravertebral region cytoma (Goldman et al, 1988), with which it may be of the chest, in the appropriate age group. confused histologically. In part, at least, this may account for the variable and moderate post-contrast Acknowledgments medium enhancement seen on CT examination. We would like to thank Erlinda S. Alabastro for typing the Although more recently significantly improved manuscript and Robert Czimny and Kelly Duggan for disease-free survival has been shown (Soule et al, 1978), survival rates with extraskeletal Ewing sarcoma are still preparing the illustrations. poor and both local recurrence and distant metastases develop frequently. As with other soft-tissue sarcomas References metastatic spread is predominantly to the lungs. ANGERVALL, L. & ENZINGER, F. M., 1975. Extraskeletal Accordingly, CT examination of the lungs should be neoplasm resembling Ewing sarcoma. Cancer, 36, 240-251. part of the initial staging procedure provided metastatic CADMAN, N. L., SOULE, E. H. & KELLY, P. J., 1965. Synovial sarcoma. An analysis of 134 tumors. Cancer, 18, 613-627. disease has not already been revealed by conventional GILLESPIE, J. J., ROTH, L. M , WILLS, E. R., EINHORN, L. H. & radiography. WILLMAN, J., 1979. Extraskeletal Ewing sarcoma: histologic The diagnosis of extraskeletal Ewing sarcoma is made and ultrastructural observations in three cases. American primarily on the basis of light and electron microscopic Journal of Surgical Pathology, 3, 99-109. features which can in most cases help separate it from GOLDING, S. J. & HUSBAND, J. E., 1982. The role of computed other round cell tumours, malignant lymphoma and tomography in the management of soft tissue sarcomas. haemangiopericytoma. Certain clinical and radiological British Journal of Radiology, 55, 740-747. features may help distinguish it from more common GOLDMAN, S. M., DAVIDSON, A. J. & NEAL, J., 1988. soft-tissue neoplasms such as malignant fibrous histiocyRetroperitoneal and pelvic hemangiopericytomas: clinical radiologic and pathologic correlation. Radiology, 168, 13-17. toma, liposarcoma and synovial sarcoma. Malignant fibrous histiocytoma of soft tissues usually presents after LORIGAN, J. G., O'KEEFFE, F. N., EVANS, H. L. & WALLACE, S., 1989. The radiologic manifestations of alveolar soft-part the age of 45 and may contain calcification (Ros et al, sarcoma. American Journal of Roentgenology, 153, 335-339. 1984). Liposarcoma is also uncommon before the age of J. P., BALLINGER JR, E. W. & ALEXANDER, W., 1978. 30 years and will contain fat if well differentiated. MAHONEY, So-called extraskeletal Ewing sarcoma. American Journal of Synovial sarcoma (Cadman et al, 1965) and the rare Clinical Pathology, 70, 926-931. alveolar soft part sarcoma (Lorigan et al, 1985), which MEISTER, P. & GOKEL, J. M., 1978. Extraskeletal Ewing occur in a similar age group and commonly in the thigh, sarcoma. Virchows Archive (A), 70, 926-931. are characteristically hypervascular. In addition, calcifi- Ros, P. R., VIAMONTE J R , M. & RYWLIN, A. M., 1984. Malignant fibrous histiocytoma: Mesenchymal tumour of cation may be seen in up to 30% of patients with ubiquitous origin. American Journal of Roentgenology, 142, synovial sarcoma. 753-759. Subacute tumour haemorrhage may lead to confusion J. S., HERMANN, G., MENDELSON, D. S. & AMBINDER, E. with fat containing tumours or skeletal muscle haeman- ROSE, P., 1983. Extraskeletal Ewing sarcoma with computed giomas on MRI owing to the presence of high signal tomography correlation. Skeletal Radiology, 9, 234-237'. intensity on both Tx and T2 weighted images. Skeletal SOULE, E. M , NEWTON, W., MOON, T. E. & TEFFT, M., 1978. muscle haemangiomas are not as bright as subcutaneous Extraskeletal Ewing's sarcoma. A preliminary review of 26 fat on r, weighted and much brighter than subcutacases encountered in the intergroup rhabdomyosarcoma study. Cancer, 42, 259-264. neous fat on T2 weighted images, usually have an overall serpiginous pattern and may be associated with focal TEFFT, M., VAWTER, G. F. & Mrrus, A., 1969. Paravertebral round cell tumors in children. Radiology, 92, 1501-1509. muscle atrophy (Yuh et al, 1987), whereas subacute haemorrhage tends to be focal and homogeneous. A CT WIGGER, H. J., SALAZAR, G. H. & BLANC, W. A., 1977. Extraskeletal Ewing sarcoma: an ultrastructural study. examination will readily distinguish fat containing Archives of Pathology and Laboratory Medicine, 101, tumours. 446-449. We have discussed the radiological findings in 22 YUH, W. T. C , KATHOL, M. H., SEIN, M. A., EHARA, S. & patients with extraskeletal Ewing sarcoma. Despite the CHIU, L., 1987. Hemangiomas of skeletal muscle: MR relative rarity of this tumour, it should be included in findings in five patients. American Journal of Roentgenology, the differential diagnosis of a non-calcified soft-tissue 149, 765-768.
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The British Journal of Radiology, June 1990
Radiological features of extraskeletal Ewing sarcoma By Francis O'Keeffe, M D , James G. Lorigan, M D and Sidney Wallace, M D Department of Diagnostic Radiology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030, USA
(Received September 1989)
Abstract. The radiological features of extraskeletal Ewing sarcoma were reviewed in 22 patients whose average age was 22 years. Tumours were located in the extremities (11 patients), abdomen or pelvis (six patients) and the chest (five patients). The tumours ranged in size from 2 cm to 20 cm, were mainly well circumscribed and showed no evidence of calcification prior to treatment. Most tumours (13 out of 14) were of low attenuation or contained areas of lower attenuation than muscle on computed tomographic examination, and in six out of seven patients studied by ultrasound the tumours were hypoechoic or partly anechoic. No distinctive post-contrast medium enhancement pattern on CT examination (11 patients) or angiographic features (three patients) were evident. Tumour haemorrhage was a frequent microscopic finding and changes consistent with this were present in one patient on magnetic resonance imaging examination. Distant metastases or local recurrence developed in 13 patients with lung being the most frequent metastatic site (eight patients). Although its radiological features are non-specific, extraskeletal Ewing sarcoma should be included in the differential diagnosis of noncalcified soft-tissue tumours especially in a young age group and where located in an extremity or paravertebral region of the chest.
Extraskeletal Ewing sarcoma is a rare soft-tissue tumour which is histologically and ultrastructurally indistinguishable from the osseous form (Angervall & Enzinger, 1975), although it occurs in an older age group and has a predilection for different sites. The diagnosis is made on the basis of the histologic findings (Mahoney et al, 1978; Gillespie et al, 1979) in the absence of bone involvement. In many cases, the extraskeletal origin can be established radiologically although operative evaluation and microscopic examination may be required. It is important that this tumour be distinguished from other round cell tumours, for which specific treatment exists and whose biological behaviour is better known. Accordingly, we reviewed the radiological features in 22 patients.
specimens in six patients) and by radiological evaluation. This included conventional radiography in all 22 patients, computed tomography (CT) in 14, ultrasound in seven, angiography in three, and magnetic resonance imaging (MRI) (1.5T Signa Scanner, GE, Milwaukee, WI) in one patient. Three of the patients examined by CT had unenhanced studies only, and the remainder had both pre- and post-contrast medium examinations. Radionuclide studies with technetium methylene diphosphate ("Tcm MDP) were performed in 12 patients. Results Clinical data
The patients were identified through a search of the data base maintained by the Department of Patient Studies at M. D. Anderson Cancer Center having presented between 1975 and 1986. Histological criteria for diagnosis included the presence of sheets of round or ovoid cells separated by fibrous trabeculae with finely divided nuclear chromatin, a minute nucleolus and distinct nuclear membrane (Angervall & Enzinger, 1975). The presence of intracellular glycogen stores and other ultrastructural findings (Wigger et al, 1977; Mahoney et al, 1978; Gillespie et al, 1979) were used to distinguish it from other round cell tumours. Evidence for extraskeletal origin of tumour was provided by operative findings in 19 patients (including microscopic examination of resected adjacent bone
There were 13 male and 9 female patients in the study group. The age range was 4-52 years (average age, 22 years). Tumour locations were in an extremity (11 patients), abdomen or pelvis (six patients) and thorax (five patients). Of the 11 extremity lesions, seven were located in a lower and four in an upper limb. The abdominal and pelvic tumours were extraperitoneal, originating from the posterior pelvis (two patients), anterior abdominal wall (two patients), bladder dome and posterior subhepatic region (one patient each). All five chest tumours arose from the soft tissues of the chest wall: three were paravertebral and two axillary in location. Tumour size ranged from 2 cm to 20 cm. Thirteen patients presented with a palpable mass. Pain was reported in nine patients, pleuritic infiveand abdominal or pelvic in two patients each. One patient presented with a painful rapidly enlarging abdominal wall mass due to spontaneous tumour haemorrhage.
Address correspondence to F. O'Keeffe, MD, Department of Paediatric Radiology, The University of Texas Medical Branch, Child Health Center, Galveston, Texas 77550, USA and reprint requests to Sidney Wallace, MD.
Soft-tissue mass The tumour was well circumscribed in 16 patients as seen on either ultrasound or CT examination and in one patient on MRI examination. In eight of these patients a
Materials and methods
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The British Journal of Radiology, June 1990
Extra skeletal Ewing sarcoma
(a) (b) Figure 1. An 18-year-old female patient with right chest mass, (a) Non-contrast medium enhanced CT shows a large mass predominantly of low attenuation. A chest tube has been inserted for pleural effusion drainage and a hydropneumothorax is present, (b) On this post-contrast medium CT tumour enhancement is evident. At surgery, diaphragmatic pleural involvement was present.
pseudofibrous capsule was present at pathological inspection. Conventional radiographs were of limited value in defining these tumours, and revealed no abnormality in three patients with small lesions in an extremity. Chest lesions were masked on the chest radio-
graph in three patients by the presence of a pleural effusion. Despite the tumour being apparently well circumscribed in two patients with chest lesions, microscopic involvement of the lung was present. Prior to treatment there was no radiological evidence of tumour
Figure 2. A 12-year-old boy with extraperitoneal subfascial mass arising from the lower abdominal wall, (a) On postcontrast medium CT the mass is of lower attenuation than muscle and relatively well circumscribed, (b) Selective inferior epigastric angiogram shows a relatively hypovascular mass. The tumour also received blood supply from the superficial circumflex iliac artery (not shown). Vol. 63, No. 750
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F. O'Keeffe, J. G. Lorigan and S. Wallace
Figure 3. A 21-year-old man with tumour haemorrhage, (a) Sagittal T, weighted spin-echo image, 600/20 shows large mass with hyperintense areas, (b) On axial T2 weighted spin-echo image, 2000/80, hyperintense signal persists (arrow) consistent with subacute haemorrhage.
calcification, although in two patients, who were receiving chemotherapy prior to resection, small areas of amorphous calcification developed. Tumours were of low attenuation or contained areas of low attenuation (Fig. 1) with respect to muscle in 13 of 14 patients on unenhanced CT examination. The sonographic features in seven patients were mainly those of either a hypoechoic (four patients) or a partly anechoic mass (two patients). In the other patient studied, the tumour had a mixed echo pattern. 458
Figure 4. An 18-year-old female patient with left calf tumour, (a) Conventional radiograph shows periosteal reaction (arrows) in the adjacent tibia, (b) Pre- and post-contrast medium CT scans show tumour rim enhancement. At surgery, a fibrous pseudocapsule was present. The tumour did not invade the periosteum.
Tumour vascularity was variable as evident from angiography and contrast medium enhanced CT examinations. Angiography demonstrated moderately hypervascular tumours in two patients and a hypovascular tumour in one patient (Fig. 2). Early draining veins were The British Journal of Radiology, June 1990
Extra skeletal Ewing sarcoma
parietal lobe metastasis 5 years after initial diagnosis and marked post-contrast medium enhancement of a brain metastasis in another patient. Histological and ultrastructural analysis of the lesions was consistent with extraosseous Ewing tumour. Cystic intraperitoneal metastases developed in one patient (Fig. 5).
Figure 5. Intraperitoneal metastases from pelvic tumour. Contrast medium enhanced CT shows omental lesions (arrows). The larger lesion has a mural nodule.
not seen. Tumour enhancement was shown in four out of 11 patients who had contrast medium enhanced scans. Areas of haemorrhage within the tumour were evident at microscopy in seven patients and in one of these MRI (Fig. 3) revealed areas of high signal intensity on both T, and T2 weighted images in a predominantly low signal mass consistent with subacute haemorrhage. Spontaneous bleeding around the tumour occurred in one patient who presented with a rectus sheath haematoma and this was evident as a hypoechoic mass on ultrasound. Adjacent bone changes
One patient had a bone abnormality felt to be a reactive change to the adjacent soft-tissue mass. Periosteal reaction was present on a conventional radiograph (Fig. 4) with corresponding increased radionuclide uptake at the site of periosteal reaction. At surgery the tumour had a fibrous pseudocapsule and was adjacent to but did not involve the periosteum. Twelve patients had radionuclide studies with technetium methylene diphosphate ("Tcm MDP) and only one (described above) had abnormal radionuclide uptake. Recurrent and metastatic disease
Distant metastases (10 patients) or local recurrence (six patients) developed in 13 patients. Five patients had distant metastases at presentation. The time interval for local recurrence was between 3 months and 2 years. Eleven patients died between 6 months and 10 years after presentation and 11 are alive between 2 and 10 years after presentation, nine without measurable disease. The most frequent metastatic site was lung (eight patients) followed by liver and brain (three patients each). Of particular interest was the clinical presentation in one patient with spontaneous haemorrhage from a Vol. 63, No. 750
Discussion Although Tefft et al (1969) reported four cases of paravertebral round cell tumours of the chest closely resembling Ewing sarcoma of bone morphologically, the pathological features of extraskeletal Ewing sarcoma were first described in 1975 (Angervall et al). In that series of 35 patients, the tumours were frequently located in the soft tissues of the extremities or paravertebral region of the chest, although they have been described in almost all sites where other sarcomas are found. Unlike the osseous form there is no apparent sex predilection, patients are older with a median age of about 20 years and the trunk is a common site of occurrence. Occurrence before five years is unusual (Soule et al, 1978). Patients with extremity lesions usually present with a painless mass, but tumours arising elsewhere may be painful. All of our patients with chest lesions presented with pleuritic pain. Unusually the patient may present with a painful and rapidly enlarging mass due to spontaneous haemorrhage. Distant metastases, most frequently to the lung, are not uncommon at presentation. There may be no findings on conventional radiographs. When present, they are usually of a non-specific mass which can vary widely in size. Tumour calcification was not present in our series and to date has not been reported in the untreated patient. When adjacent bone changes are present, histological examination is necessary to separate it from the osseous form. The osseous form should show involvement of the marrow cavity by CT (Rose et al, 1983) or MRI. Angervall et al (1975) suggested that the rare and late occurrence of osseous involvement made it unlikely that this entity was just an initial soft-tissue manifestation of a skeletal Ewing sarcoma. The gross specimen often has a pseudocapsule and accordingly appears well circumscribed on CT, ultrasound or MRI examination. However, the tumour may be poorly circumscribed histologically (Meister & Gokel, 1978). Extraskeletal Ewing sarcoma is most frequently hypoechoic on ultrasound scans and on CT scans of low attenuation. These are non-specific findings seen with most soft-tissue sarcomas (Golding & Husband, 1982) and reflect the frequent microscopic findings of necrosis sometimes with cyst formation (Angervall et al, 1975; Wigger et al, 1977). Spontaneous tumour haemorrhage may alter the appearances with any of these imaging modalities or, as in two of our patients, may be the presenting feature. The angiographic appearances of this tumour are not distinctive and, although we studied only a small number of patients, it is not universally hypervascular 459
F. O'Keeffe, J. G. Lorigan and S. Wallace
unlike other soft-tissue tumours such as haemangioperi- mass, especially in an extremity or paravertebral region cytoma (Goldman et al, 1988), with which it may be of the chest, in the appropriate age group. confused histologically. In part, at least, this may account for the variable and moderate post-contrast Acknowledgments medium enhancement seen on CT examination. We would like to thank Erlinda S. Alabastro for typing the Although more recently significantly improved manuscript and Robert Czimny and Kelly Duggan for disease-free survival has been shown (Soule et al, 1978), survival rates with extraskeletal Ewing sarcoma are still preparing the illustrations. poor and both local recurrence and distant metastases develop frequently. As with other soft-tissue sarcomas References metastatic spread is predominantly to the lungs. ANGERVALL, L. & ENZINGER, F. M., 1975. Extraskeletal Accordingly, CT examination of the lungs should be neoplasm resembling Ewing sarcoma. Cancer, 36, 240-251. part of the initial staging procedure provided metastatic CADMAN, N. L., SOULE, E. H. & KELLY, P. J., 1965. Synovial sarcoma. An analysis of 134 tumors. Cancer, 18, 613-627. disease has not already been revealed by conventional GILLESPIE, J. J., ROTH, L. M , WILLS, E. R., EINHORN, L. H. & radiography. WILLMAN, J., 1979. Extraskeletal Ewing sarcoma: histologic The diagnosis of extraskeletal Ewing sarcoma is made and ultrastructural observations in three cases. American primarily on the basis of light and electron microscopic Journal of Surgical Pathology, 3, 99-109. features which can in most cases help separate it from GOLDING, S. J. & HUSBAND, J. E., 1982. The role of computed other round cell tumours, malignant lymphoma and tomography in the management of soft tissue sarcomas. haemangiopericytoma. Certain clinical and radiological British Journal of Radiology, 55, 740-747. features may help distinguish it from more common GOLDMAN, S. M., DAVIDSON, A. J. & NEAL, J., 1988. soft-tissue neoplasms such as malignant fibrous histiocyRetroperitoneal and pelvic hemangiopericytomas: clinical radiologic and pathologic correlation. Radiology, 168, 13-17. toma, liposarcoma and synovial sarcoma. Malignant fibrous histiocytoma of soft tissues usually presents after LORIGAN, J. G., O'KEEFFE, F. N., EVANS, H. L. & WALLACE, S., 1989. The radiologic manifestations of alveolar soft-part the age of 45 and may contain calcification (Ros et al, sarcoma. American Journal of Roentgenology, 153, 335-339. 1984). Liposarcoma is also uncommon before the age of J. P., BALLINGER JR, E. W. & ALEXANDER, W., 1978. 30 years and will contain fat if well differentiated. MAHONEY, So-called extraskeletal Ewing sarcoma. American Journal of Synovial sarcoma (Cadman et al, 1965) and the rare Clinical Pathology, 70, 926-931. alveolar soft part sarcoma (Lorigan et al, 1985), which MEISTER, P. & GOKEL, J. M., 1978. Extraskeletal Ewing occur in a similar age group and commonly in the thigh, sarcoma. Virchows Archive (A), 70, 926-931. are characteristically hypervascular. In addition, calcifi- Ros, P. R., VIAMONTE J R , M. & RYWLIN, A. M., 1984. Malignant fibrous histiocytoma: Mesenchymal tumour of cation may be seen in up to 30% of patients with ubiquitous origin. American Journal of Roentgenology, 142, synovial sarcoma. 753-759. Subacute tumour haemorrhage may lead to confusion J. S., HERMANN, G., MENDELSON, D. S. & AMBINDER, E. with fat containing tumours or skeletal muscle haeman- ROSE, P., 1983. Extraskeletal Ewing sarcoma with computed giomas on MRI owing to the presence of high signal tomography correlation. Skeletal Radiology, 9, 234-237'. intensity on both Tx and T2 weighted images. Skeletal SOULE, E. M , NEWTON, W., MOON, T. E. & TEFFT, M., 1978. muscle haemangiomas are not as bright as subcutaneous Extraskeletal Ewing's sarcoma. A preliminary review of 26 fat on r, weighted and much brighter than subcutacases encountered in the intergroup rhabdomyosarcoma study. Cancer, 42, 259-264. neous fat on T2 weighted images, usually have an overall serpiginous pattern and may be associated with focal TEFFT, M., VAWTER, G. F. & Mrrus, A., 1969. Paravertebral round cell tumors in children. Radiology, 92, 1501-1509. muscle atrophy (Yuh et al, 1987), whereas subacute haemorrhage tends to be focal and homogeneous. A CT WIGGER, H. J., SALAZAR, G. H. & BLANC, W. A., 1977. Extraskeletal Ewing sarcoma: an ultrastructural study. examination will readily distinguish fat containing Archives of Pathology and Laboratory Medicine, 101, tumours. 446-449. We have discussed the radiological findings in 22 YUH, W. T. C , KATHOL, M. H., SEIN, M. A., EHARA, S. & patients with extraskeletal Ewing sarcoma. Despite the CHIU, L., 1987. Hemangiomas of skeletal muscle: MR relative rarity of this tumour, it should be included in findings in five patients. American Journal of Roentgenology, the differential diagnosis of a non-calcified soft-tissue 149, 765-768.
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The British Journal of Radiology, June 1990
