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337
Pictorial .
Essay
:
MR Imaging Marilyn
J. Morton,1
of Synovial
Thomas
H. Berquist,1
Sarcoma
Richard
A. McLeod,1
The MR imaging findings in 12 cases of synoviab sarcoma are illustrated. The MR appearance most indicative of the tumor is an inhomogeneous septated mass with infiltrative margins located close to a joint, a tendon, or bursae, especially if soft-tissue calcification can be seen on CT scans or plain radiographs.
K. Krishnan
Materials
January
documented
Department
of Orthopedics,
Mayo
Clinic and Mayo
February 1991 0361-803X/91/1562-0337
Foundation,
Rochester,
© American
i 989, i 2 patients
sarcoma
underwent
All images
were
with histo-
preoperative
The clinical records, in these obtained
as-
MR
i 2 patients
were
before
treat-
any
included 1 0 males and two females ranging in age 73 years (mean age, 34 years). MR imaging studies were performed with a 1 .5-T Signa magnet (General Electric, Milwaukee, WI) and a 0.i 5-T Picker magnet (Picker International, Highland Heights, OH). Images were obtained by using both Ti-weighted, 400-800/20 (TRITE), and T2-weighted, 2000/20-30,60-80, spinecho (SE) sequences. The i 2 synovial sarcomas included i i untreated lesions and one local tumor recurrence. Three of the tumors were in an upper extremity (two wrists, one elbow) and nine were in a lower extremity or ment.
The
from
i i to
pelvic
group
girdle (four thighs,
two buttocks,
two ankles,
one knee).
Eight
synovial sarcomas were located within 5 cm of or adjacent to joints, tendons, or bursae, and one was intraarticular, arising from the anterior joint capsule of the ankle. The remaining three tumors were located in the thigh at a site removed from the adjacent joint. The mean diameter of the tumors was 9.2 cm (range, 2.5-i 5.0 cm).
MR Imaging
Appearance
On MR images, nine of the i 2 synoviab sarcomas had a heterogeneous, mubtiboculan configuration with various degrees of internal septation (Figs. i and 2). Three of these multiloculan lesions had a striking configuration of extensive boculations with multiple fluid-fluid levels (Figs. 3 and 4). In
Received June 4, 1 990; accepted after revision August 27, 1990. I Department of Diagnostic Radiology, Mayo Clinic and Mayo Foundation, Rochester, MN 55905. Division of Surgical Pathology, Mayo Clinic and Mayo Foundation, Rochester, MN 55905.
3
synovial
retrospectively.
2
AJR 156:337-340,
1983 and August
sessment by MR imaging at our institution. imaging studies, and pathologic specimens reviewed
Synovial sarcoma constitutes approximately i 0% of all softtissue sarcomas [i ]. Although synovial sarcoma frequently occurs close to joints, tendons, and bunsae, it rarely arises from the intnaarticulan synovial lining of these structures. Rather, it is considered to arise de novo from primitive mesenchymal cells that differentiate sufficiently to resemble synovial membrane. Synovial sarcoma may occur at any age but is most commonly seen between the ages of 20 and 40 years. Prognosis is generally poor (5-year survival nate, 55%) [2]. MR imaging is the most valuable imaging technique for the preoperative anatomic staging of soft-tissue tumors of the muscuboskeletal system. MR imaging is less useful in predicting tumor histology and in differentiating benign from mabignant soft-tissue masses [3]. Nevertheless, on the basis of combined clinical data and MR imaging features, the nature of a musculoskebetab mass often can be determined. We retrospectively reviewed the MR imaging features in i 2 cases of synovial sarcoma and noted several MR imaging features that may contribute to a presumptive diagnosis of these softtissue sarcomas.
H. Sim3
and Methods
Between logically
Unni,2 and Franklin
MN 55905.
Roentgen Ray Society
Address
reprint
requests
to M. J. Morton.
MORTON
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338
ET AL.
AJA:156,
February
1991
Fig. 1.-Multilocular synovial sarcoma of right posterior gluteal region. A, Axial MR image, SE 600/20, of prone patient shows large inhomogeneous tumor mass in right buttock posterior to hip joint. Central areas of bright signal intensity (arrow) (short Ti) indicate subacute hemorrhage. Biopsy had not been performed before MR study. B, On T2-weighted MR image, SE 2000/60, inhomogeneous, septated configuration is more apparent. Tumor margin abuts gluteal neurovascular bundle (arrow). At surgery, vascular encasement was found.
A
B
Fig. 2.-Multilocular synovial sarcoma of proximal left thigh. A, Coronal MR image, SE 650/20, shows lobulated, septated mass (arrows) in medial left thigh about 5 cm below hip joint. B, On transaxial MR image, SE 2000/60, tumor is detected within great adductor muscle. Lesion inhomogeneity and internal sepia (arrows) are more conspicious on T2-weighted image.
Fig. 3.-Multilocular synovial sarcoma with fluid-fluid levels. A and B, Axial SE 600/20 (A) and SE 2000/60 (B) MR images of prone patient (same patient as in Fig. 1 but at a more inferior scan level) show fluid-fluid levels adjacent to irregular tumor mass in right buttock. Signal intensities of fluid levels, notably short TI of supernatant (curved arrows) and short T2 of sediment (straight solid arrows) are characteristic of diffusional and paramagnetic effects of degraded hemoglobin. Signal intensity of fluid levels indicated that hemorrhage had occurred within areas of necrosis or cyst formation. Infiltrative tumor margins and tumor extension along posterior ischium (open arrows) are evident on T2-weighted image.
eight of the 12 synovial sarcomas, components of the tumor margins were poorly defined and infiltrative, which are MR imaging features more characteristic of malignant soft-tissue tumors. Eleven of the i 2 lesions (including all nine multilocular
lesions) displayed a signal intensity similar to that of skeletal muscle on Ti -weighted images and equal to on slightly greaten than that of subcutaneous fat on T2-weighted images. In the one exception, the MR signal intensity was similar to that of
MR
AJR:156, February 1991
Fig. 4.-Synovial
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extensive els.
sarcomas
in two patients
OF
SYNOVIAL
SARCOMA
339
have
loculations with multiple fluid-fluid 1ev-
A and B, Axial MR images, SE 2000/60, of proximal right thigh (A) and left gluteal region (B). Supernatant (curved arrows) and sediment (straight solid arrows) have signal intensities identical to those of lesion in Fig. 3. Lesion in A shows infiltrative tumor margins posteriorly (open arrow) obliterating neurovascular bundle. Sciatic nerve involvement was confirmed at surgery.
A
B
Fig. 5.-Small (5 cm) synovial sarcoma in thenar region of hand. A and B, TI-weighted, SE 600/20 (A), and T2-weighted, SE 2000/60 (B), MR images both show homogeneous low signal intensity. Tumor margins are sharp, and lesion is circumscribed peripherally by low-signal-intensity rim. These combined morphologic features of lesion homogeneity and sharp margins are more characteristic of benign soft-tissue neoplasms. Absence of necrosis and hemorrhage in this small synovial sarcoma is most likely explanation for lesion homogeneity and absence of loculations.
skeletal muscle on both Ti - and T2-weighted images. This mass also had a uniform homogeneous signal intensity and well-defined margins (Fig. 5). Neunovascular involvement was suspected in five cases in which the tumor margin abutted and displaced the neunovascular bundle. Neurovascuban encasement was confirmed at operation in two of these cases. The MR studies in our series failed to show small punctate areas of soft-tissue calcification that were discernible on nadiographs in three patients.
Discussion Synovial sarcoma is a rare, malignant mesenchymab neoplasm that occurs chiefly in the extremities of young adults. It occurs primarily in the paraarticulan regions, usually close to tendon sheaths, bursae, and joint capsules. However,
Fig.
6.-Axial
shows synovial
MR
image,
sarcoma
SE
adjacent
2000/60,
to ankle.
Large lobulated mass with multiple septa has inhomogeneous signal intensity slightly greater than that of fat. Small focus of hyperintense signal (arrow) is most likely due to cyst formation or necrosis.
origin from anatomic synovial lining is uncommon. The predominant feature on the MR images in these 1 2 cases of synoviab sarcoma was the configuration of a heterogeneous, multiloculan mass with internal septa (nine cases). Three tumors had a distinct feature of extensive loculations with multiple fluid-fluid levels. The signal intensities of these fluid bevels were considered to be characteristic of sedimented blood products, indicating the presence of hemorrhage within areas of cyst formation on necrosis. The MR studies showed that nine of the synoviab sarcomas were inhomogeneous lesions, and eight of these had infiltrative tumor margins. In our experience, these combined morphobogic features have been useful predictors of the malignant nature of soft-tissue neoplasms (Benquist TH et al., unpublished data). Only one tumor showed a homogeneous signal intensity and sharp mangination, features more commonly seen in benign neoplasms. This same tumor was unique in
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340
MORTON
that it was the only synovial sarcoma to have low signal intensity on T2-weighted images. Pathologic examination of this lesion revealed the usual histologic components of synovial sarcoma, and a histologic basis for the decreased signal on the T2-weighted images could not be found-that is, hypocellulanity and abundant fibrous elements were not evident. A septated configuration has also been reported to be a characteristic MR feature in two types of benign soft-tissue masses: hemangiomas and synovial and ganglionic cysts [4, 5]. Typically, these soft-tissue masses are sharply marginated and have a homogeneous hypenintense signal that is much brighten than that of the subcutaneous fat on T2-weighted images [4, 5]. Homogeneous high signal intensity on T2weighted images was not a feature in any of the synoviab sarcomas in our series (Fig. 6). An important feature of synovial sarcoma is the presence of focal calcification, which can be demonstrated on radiographs in up to 30% of patients [i ]. Three synoviab sarcomas in this series showed small punctate areas of calcification on CT scans on nadiognaphs. These calcifications were not detectable by MR imaging. Because MR imaging is insensitive
ET AL.
AJA:156,
February
1991
to the presence of soft-tissue calcification, we believe that all MR images of bone and soft-tissue tumors should be interpreted with corresponding radiognaphs on CT scans. Although these MR findings cannot be considered specific for synovial sarcoma, an awareness of the typical morphologic appearance may aid in the preoperative recognition of these lesions. The finding of an inhomogeneous, septated mass with infiltrative margins located close to a joint, a tendon, on bursae should suggest the presence of synovial sarcoma, especially if soft-tissue calcification can be identified on CT scans or plain radiognaphs. REFERENCES 1 . Cadman NL, Soule EH, Kelly PJ. Synovial sarcoma: an analysis of 134 tumors. Cancer 1965;18:61 3-627 2. Wright PH, Sim FH, Soule EH, Taylor WE. Synovial sarcoma. J Bone Joint Surg [Am] 1982;64-A: 112-122 3. Kransdorf MJ, Jelinek JS, Moser AP Jr. Soft-tissue masses: diagnosis using MA imaging.AJR 1989:153:541-546 4. Burk DL Jr, Dalinka MK, Kanal E, et al. Meniscal and ganglion cysts of the knee: MA evaluation. AJR i988;150:331-336 5. Kaplan PA, Williams SM. Mucocutaneous and peripheral soft-tissue hemangiomas: MA imaging. Radiology 1987;1 63:163-166
337
Pictorial .
Essay
:
MR Imaging Marilyn
J. Morton,1
of Synovial
Thomas
H. Berquist,1
Sarcoma
Richard
A. McLeod,1
The MR imaging findings in 12 cases of synoviab sarcoma are illustrated. The MR appearance most indicative of the tumor is an inhomogeneous septated mass with infiltrative margins located close to a joint, a tendon, or bursae, especially if soft-tissue calcification can be seen on CT scans or plain radiographs.
K. Krishnan
Materials
January
documented
Department
of Orthopedics,
Mayo
Clinic and Mayo
February 1991 0361-803X/91/1562-0337
Foundation,
Rochester,
© American
i 989, i 2 patients
sarcoma
underwent
All images
were
with histo-
preoperative
The clinical records, in these obtained
as-
MR
i 2 patients
were
before
treat-
any
included 1 0 males and two females ranging in age 73 years (mean age, 34 years). MR imaging studies were performed with a 1 .5-T Signa magnet (General Electric, Milwaukee, WI) and a 0.i 5-T Picker magnet (Picker International, Highland Heights, OH). Images were obtained by using both Ti-weighted, 400-800/20 (TRITE), and T2-weighted, 2000/20-30,60-80, spinecho (SE) sequences. The i 2 synovial sarcomas included i i untreated lesions and one local tumor recurrence. Three of the tumors were in an upper extremity (two wrists, one elbow) and nine were in a lower extremity or ment.
The
from
i i to
pelvic
group
girdle (four thighs,
two buttocks,
two ankles,
one knee).
Eight
synovial sarcomas were located within 5 cm of or adjacent to joints, tendons, or bursae, and one was intraarticular, arising from the anterior joint capsule of the ankle. The remaining three tumors were located in the thigh at a site removed from the adjacent joint. The mean diameter of the tumors was 9.2 cm (range, 2.5-i 5.0 cm).
MR Imaging
Appearance
On MR images, nine of the i 2 synoviab sarcomas had a heterogeneous, mubtiboculan configuration with various degrees of internal septation (Figs. i and 2). Three of these multiloculan lesions had a striking configuration of extensive boculations with multiple fluid-fluid levels (Figs. 3 and 4). In
Received June 4, 1 990; accepted after revision August 27, 1990. I Department of Diagnostic Radiology, Mayo Clinic and Mayo Foundation, Rochester, MN 55905. Division of Surgical Pathology, Mayo Clinic and Mayo Foundation, Rochester, MN 55905.
3
synovial
retrospectively.
2
AJR 156:337-340,
1983 and August
sessment by MR imaging at our institution. imaging studies, and pathologic specimens reviewed
Synovial sarcoma constitutes approximately i 0% of all softtissue sarcomas [i ]. Although synovial sarcoma frequently occurs close to joints, tendons, and bunsae, it rarely arises from the intnaarticulan synovial lining of these structures. Rather, it is considered to arise de novo from primitive mesenchymal cells that differentiate sufficiently to resemble synovial membrane. Synovial sarcoma may occur at any age but is most commonly seen between the ages of 20 and 40 years. Prognosis is generally poor (5-year survival nate, 55%) [2]. MR imaging is the most valuable imaging technique for the preoperative anatomic staging of soft-tissue tumors of the muscuboskeletal system. MR imaging is less useful in predicting tumor histology and in differentiating benign from mabignant soft-tissue masses [3]. Nevertheless, on the basis of combined clinical data and MR imaging features, the nature of a musculoskebetab mass often can be determined. We retrospectively reviewed the MR imaging features in i 2 cases of synovial sarcoma and noted several MR imaging features that may contribute to a presumptive diagnosis of these softtissue sarcomas.
H. Sim3
and Methods
Between logically
Unni,2 and Franklin
MN 55905.
Roentgen Ray Society
Address
reprint
requests
to M. J. Morton.
MORTON
Downloaded from www.ajronline.org by 129.187.254.46 on 11/11/14 from IP address 129.187.254.46. Copyright ARRS. For personal use only; all rights reserved
338
ET AL.
AJA:156,
February
1991
Fig. 1.-Multilocular synovial sarcoma of right posterior gluteal region. A, Axial MR image, SE 600/20, of prone patient shows large inhomogeneous tumor mass in right buttock posterior to hip joint. Central areas of bright signal intensity (arrow) (short Ti) indicate subacute hemorrhage. Biopsy had not been performed before MR study. B, On T2-weighted MR image, SE 2000/60, inhomogeneous, septated configuration is more apparent. Tumor margin abuts gluteal neurovascular bundle (arrow). At surgery, vascular encasement was found.
A
B
Fig. 2.-Multilocular synovial sarcoma of proximal left thigh. A, Coronal MR image, SE 650/20, shows lobulated, septated mass (arrows) in medial left thigh about 5 cm below hip joint. B, On transaxial MR image, SE 2000/60, tumor is detected within great adductor muscle. Lesion inhomogeneity and internal sepia (arrows) are more conspicious on T2-weighted image.
Fig. 3.-Multilocular synovial sarcoma with fluid-fluid levels. A and B, Axial SE 600/20 (A) and SE 2000/60 (B) MR images of prone patient (same patient as in Fig. 1 but at a more inferior scan level) show fluid-fluid levels adjacent to irregular tumor mass in right buttock. Signal intensities of fluid levels, notably short TI of supernatant (curved arrows) and short T2 of sediment (straight solid arrows) are characteristic of diffusional and paramagnetic effects of degraded hemoglobin. Signal intensity of fluid levels indicated that hemorrhage had occurred within areas of necrosis or cyst formation. Infiltrative tumor margins and tumor extension along posterior ischium (open arrows) are evident on T2-weighted image.
eight of the 12 synovial sarcomas, components of the tumor margins were poorly defined and infiltrative, which are MR imaging features more characteristic of malignant soft-tissue tumors. Eleven of the i 2 lesions (including all nine multilocular
lesions) displayed a signal intensity similar to that of skeletal muscle on Ti -weighted images and equal to on slightly greaten than that of subcutaneous fat on T2-weighted images. In the one exception, the MR signal intensity was similar to that of
MR
AJR:156, February 1991
Fig. 4.-Synovial
Downloaded from www.ajronline.org by 129.187.254.46 on 11/11/14 from IP address 129.187.254.46. Copyright ARRS. For personal use only; all rights reserved
extensive els.
sarcomas
in two patients
OF
SYNOVIAL
SARCOMA
339
have
loculations with multiple fluid-fluid 1ev-
A and B, Axial MR images, SE 2000/60, of proximal right thigh (A) and left gluteal region (B). Supernatant (curved arrows) and sediment (straight solid arrows) have signal intensities identical to those of lesion in Fig. 3. Lesion in A shows infiltrative tumor margins posteriorly (open arrow) obliterating neurovascular bundle. Sciatic nerve involvement was confirmed at surgery.
A
B
Fig. 5.-Small (5 cm) synovial sarcoma in thenar region of hand. A and B, TI-weighted, SE 600/20 (A), and T2-weighted, SE 2000/60 (B), MR images both show homogeneous low signal intensity. Tumor margins are sharp, and lesion is circumscribed peripherally by low-signal-intensity rim. These combined morphologic features of lesion homogeneity and sharp margins are more characteristic of benign soft-tissue neoplasms. Absence of necrosis and hemorrhage in this small synovial sarcoma is most likely explanation for lesion homogeneity and absence of loculations.
skeletal muscle on both Ti - and T2-weighted images. This mass also had a uniform homogeneous signal intensity and well-defined margins (Fig. 5). Neunovascular involvement was suspected in five cases in which the tumor margin abutted and displaced the neunovascular bundle. Neurovascuban encasement was confirmed at operation in two of these cases. The MR studies in our series failed to show small punctate areas of soft-tissue calcification that were discernible on nadiographs in three patients.
Discussion Synovial sarcoma is a rare, malignant mesenchymab neoplasm that occurs chiefly in the extremities of young adults. It occurs primarily in the paraarticulan regions, usually close to tendon sheaths, bursae, and joint capsules. However,
Fig.
6.-Axial
shows synovial
MR
image,
sarcoma
SE
adjacent
2000/60,
to ankle.
Large lobulated mass with multiple septa has inhomogeneous signal intensity slightly greater than that of fat. Small focus of hyperintense signal (arrow) is most likely due to cyst formation or necrosis.
origin from anatomic synovial lining is uncommon. The predominant feature on the MR images in these 1 2 cases of synoviab sarcoma was the configuration of a heterogeneous, multiloculan mass with internal septa (nine cases). Three tumors had a distinct feature of extensive loculations with multiple fluid-fluid levels. The signal intensities of these fluid bevels were considered to be characteristic of sedimented blood products, indicating the presence of hemorrhage within areas of cyst formation on necrosis. The MR studies showed that nine of the synoviab sarcomas were inhomogeneous lesions, and eight of these had infiltrative tumor margins. In our experience, these combined morphobogic features have been useful predictors of the malignant nature of soft-tissue neoplasms (Benquist TH et al., unpublished data). Only one tumor showed a homogeneous signal intensity and sharp mangination, features more commonly seen in benign neoplasms. This same tumor was unique in
Downloaded from www.ajronline.org by 129.187.254.46 on 11/11/14 from IP address 129.187.254.46. Copyright ARRS. For personal use only; all rights reserved
340
MORTON
that it was the only synovial sarcoma to have low signal intensity on T2-weighted images. Pathologic examination of this lesion revealed the usual histologic components of synovial sarcoma, and a histologic basis for the decreased signal on the T2-weighted images could not be found-that is, hypocellulanity and abundant fibrous elements were not evident. A septated configuration has also been reported to be a characteristic MR feature in two types of benign soft-tissue masses: hemangiomas and synovial and ganglionic cysts [4, 5]. Typically, these soft-tissue masses are sharply marginated and have a homogeneous hypenintense signal that is much brighten than that of the subcutaneous fat on T2-weighted images [4, 5]. Homogeneous high signal intensity on T2weighted images was not a feature in any of the synoviab sarcomas in our series (Fig. 6). An important feature of synovial sarcoma is the presence of focal calcification, which can be demonstrated on radiographs in up to 30% of patients [i ]. Three synoviab sarcomas in this series showed small punctate areas of calcification on CT scans on nadiognaphs. These calcifications were not detectable by MR imaging. Because MR imaging is insensitive
ET AL.
AJA:156,
February
1991
to the presence of soft-tissue calcification, we believe that all MR images of bone and soft-tissue tumors should be interpreted with corresponding radiognaphs on CT scans. Although these MR findings cannot be considered specific for synovial sarcoma, an awareness of the typical morphologic appearance may aid in the preoperative recognition of these lesions. The finding of an inhomogeneous, septated mass with infiltrative margins located close to a joint, a tendon, on bursae should suggest the presence of synovial sarcoma, especially if soft-tissue calcification can be identified on CT scans or plain radiognaphs. REFERENCES 1 . Cadman NL, Soule EH, Kelly PJ. Synovial sarcoma: an analysis of 134 tumors. Cancer 1965;18:61 3-627 2. Wright PH, Sim FH, Soule EH, Taylor WE. Synovial sarcoma. J Bone Joint Surg [Am] 1982;64-A: 112-122 3. Kransdorf MJ, Jelinek JS, Moser AP Jr. Soft-tissue masses: diagnosis using MA imaging.AJR 1989:153:541-546 4. Burk DL Jr, Dalinka MK, Kanal E, et al. Meniscal and ganglion cysts of the knee: MA evaluation. AJR i988;150:331-336 5. Kaplan PA, Williams SM. Mucocutaneous and peripheral soft-tissue hemangiomas: MA imaging. Radiology 1987;1 63:163-166
