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Pedunculated fibrosarcoma
CASE REPORTS
Pedunculated Fibrosarcoma Unusual Presentation of an lntraabdominal Fibrosarcoma Arising From the Greater Omentum
Stanley Lipper, MD, Chapel Hill, North Carolina Edwin W. Nunnery, MD, Chapel Hill, North Carolina Kent L. Jones, MD, Chapel Hill, North Carolina
The vast majority of fibrosarcomas occur in external soft tissues [I ,2]. Primary intraabdominal examples are uncommon and have been described in the viscera [I], retroperitoneum [1,3-51, mesentery [6] and omentum [5,7,8]. Although partially encapsulated, these tumors invariably infiltrate surrounding structures, which contributes to their overall dismal prognosis [1,5,7]. We could find no reported case in which a fibrosarcoma clinically mimicking a ruptured abdominal aortic aneurysm, manifested as a virtually free-lying tumor attached to its parent omentum by a long, fibrovascular, cord-like pedicle. We therefore report this highly unusual case with light microscopic and ultrastructural observations. Case Report A 50 year old black man was in good health until he presented to his home town hospital emergency room in shock after the sudden onset of severe lower abdominal pain on the morning of admission. His blood pressure was 70/40 mm Hg and pulse 120 beats/min. Special investigations revealed a hemoglobin of 13 g/100 ml, a hematocrit of 39 percent and a white cell count of 10,800/mm3. Intravenous infusion of 1 liter of Ringer’s lactate raised the blood pressure to 110/80 mm Hg. Physical examination disclosed a large, tender, pulsatile abdominal mass. Abdominal roentgenography, including intravenous pyelography, showed superior and lateral displacement of the bowel by
a large lower abdominal mass which indented the dome of the bladder. The patient was transferred to North Carolina Memorial Hospital, where a tentative diagnosis of ruptured aortic aneurysm was made. At celiotomy a large, mobile, encapsulated mass was found (Figure 1). The tumor was suspended from the gastric omentum by an umbilical cord-like vascular pedicle 17 cm long. The source of hemorrhage was a ruptured vein at the lower end of the vascular pedicle. Delivery of the tumor was accomplished easily by resecting the omental origin of the cord and transecting a fibrous adhesion between the tumor capsule and the lower anterior abdominal wall. Tissue excised from the latter attachment site was considered on frozen-section analysis to be free of tumor. There was no evidence of intraabdominal spread of disease. The postoperative recovery was uneventful. Material
and Methods
Tissue for light microscopy was fixed in 10 percent formaldehyde solution and cut into paraffin sections. The stains used included hematoxylin-eosin and Weigert’s reticulin stain. Fresh minced tissue was fixed in phosphatebuffered, 4 percent paraformaldehyde, washed in a 0.1 M phosphate buffer and postfixed in phosphate buffered, 2 percent osmic acid. After dehydration in graded ethanol, the tissue was cleared with propylene oxide. Sections were stained with uranyl acetate and lead citrate and examined under a JEOL-JEM T7 electron microscope. Results
From the Departments of Surgical Pathology and Surgery, School of Medicine, University of North Carolina, Chapel Hill, North Carolina. Requests for reprints should be addressed to Stanley Lipper, MD, Department of Pathology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27514.
Volume 140, September 1990
Macroscopic findings: The specimen consisted of a firm, oval mass measuring 17 by 12 by 9 cm, with a smooth-surfaced, bosselated contour and a thin
457
Lipper et al
fibrous capsule (Figure 1). A 17 cm long, cord-like leash of tortuous blood vessels embedded in fibrofatty tissue inserted into the upper capsular surface through a fibrous, mesentery-like expansion. The proximal end of this cord merged with lobules of omental fat. A thin, transected fibrous adhesion was present anteriorly. The cut surface revealed a solid tumor composed of tan- to gray-colored, irregular nodules with intervening areas of hemorrhage, necrosis and cyst formation (Figure 2). A separate piece of tissue representing the excised abdominal wall attachment of the adhesion was also submitted. Microscopic findings: Sections showed the features of a fibroscarcoma with varying degrees of differentiation, ranging from moderately differen-
tiated regions composed of fusiform cells arranged in a fasciculated pattern and associated with bands of collagen and abundant reticulin, to predominantly poorly differentiated areas consisting of plump, spindle to round cells forming solid sheets devoid of reticulin (Figures 3 and 4). Mitoses were present in all areas and exceeded 40 per 10 high power fields in the most cellular and anaplastic fields. Areas of necrosis and myxoid degeneration were present. The cord structure consisted of large arteries and veins embedded in fibrofatty tissue. No tumor was identified in this tissue. The fibrous adhesion consisted of loose fibrovascular tissue and an active fibroblastic
Figure 1. Operative photograph of the tumor showing the umbilical. cord-like vascular pedicie ( shori arrow) arklng from the greater omentum and insertkg into the tumor. 77~9 clamped fibrous adhesion between the tumor and the anterior abdominal wall is also she wn ( long arrow ) .
Figure 2. Cut surface of tumor composed of tan to gray nodules w/th lntervenkg hemorrhage, necmsk and cysts.
450
F&sw 3. A, fasckks of ks/krm celk associated with bamts of collagen and retkulin. ( Hematoxylk-eosk stain; magnifkatkn X100, reduced 26 percent.) 6, retkulln stain hlghMghtkg fasckulated pattern. ( Welgert’s stain; magnifkation X100, reduced 26 percent.)
The American Journal of Surgewy
Pedunculated Fibrosarcoma
component tumor.
which lacked the cellular atypia of the
Electron microscopy: The area selected for electron microscopy consisted of closely packed, round to oval cells with a few elongated forms (Figure 5). Relatively few collagen fibers, mostly nonpolymerized, were present in the intercellular spaces
Figure 4. Poorly differentiated area composed of plump spindie ceils with frequent mitoses. inset, cellular field of round ceils in solid sheet. ( Hematoxyiin-eosin stain; magn/f/cation X200, reduced 26 percent.)
F&s-e 5. Cioseiy packed round to oval ceil with occasional elongated form; prominent rough endopiasmic reticulum is shown. (&any/ acetate and lead citrate stain; magnificatkn X4,920, reduced 46 percent. )
Volume 140, September lQQ0
(Figure 6). The nuclei showed heterochromatin clumping, with conspicuous perichromatin granules (Figure 7). The cytoplasm of many cells contained prominent rough endoplasmic reticulum (Figure 5). A striking feature was the presence of varying numbers of fine cytoplasmic filaments in many of the cells. These filaments were sometimes so numerous
Figure 6. Intercellular, nonpolymerized collagen fibers; adbcent ceil wntains psripherai myoftiaments with a dense body (long arrow), pinocytotic vesicle ( curved arrow), InteuWWu j &p&g ceil process (short arrow) and plasma membrane plaque (slanted arrow). (Uranyi acetate and lead citrate stain; magnification X23,760, reduced 46 percent. )
Figure 7. Dense aggregates of cytoplasm/c filaments; prominent perichromatin granules are present (uranyi acetate and lead citrate stain; magnifkatkn X&?,SgO,reduced 46 percent). inset, detail of perichromatin granules ( magnification X78,100).
459
Lipper et al
Figure 8. Peripherally arranged myofifaments with dense body condensation ( uranyl acetate and lead c/&ate stain; magnifkation X3 1,320, reduced 46 percent). Inset, detail of dense bodies near plasma membrane (magnification X62,460).
that they filled the cytoplasm (Figure 7). More often, they were sparse and arranged peripherally (Figures 6 and 8). Areas of dense body condensation were occasionally seen along the lengths of these filaments (Figure 8). Several intercellular junction attachments were present as well as a few plasma membrane plaques (Figure 6). Rare pinocytotic vesicles were identified (Figure 6). There was no evidence of basement membrane formation. Comments Fibrosarcomas are relatively common tumors of the soft tissues of the extremities and trunk [1,2]. The rare cases of primary intraabdominal neoplasms occur as infiltrative lesions arising in the viscera 111, retroperitoneum [1,3-S], mesocolon [6] and greater omentum [5,7,8]. The present case represents a unique example of a fibrosarcoma attached to its parent structure, the greater omentum, by a long vascular pedicle. We could find no precedent for a pedunculated fibrosarcoma in the literature, although there are several descriptions of primary, solid, invasive fibrosarcomas of the greater omentum
sult of a long-standing benign process such as occurs in the extremely rare cases of multiple benign pedunculated fibrous tumors of the omentum [9] and peritoneum [IO] and in the commonly occurring pendunculated, subserosal uterine leiomyomata VII. The better-differentiated areas of this tumor permitted a confident histologic interpretation of fibrosarcoma based on identification of the typical fasciculated, collagen- and reticulin-rich fusiform cell areas, in contrast to the poorly differentiated, solid areas devoid of reticulin. Ultrastructural examination of tissue representative of the latter component disclosed a population of cells with the characteristic features of myofibroblasts, with myofilaments occurring both as large aggregates in some cells and as peripherally arranged parallel bundles in others. These peripheral bundles sometimes showed dense body condensations close to the plasma membrane. Rare attachment plaques were present along cell membranes [12,13]. Myogenous differentiation in tumors other than those of pure smooth muscle derivation is now an established ultrastructural observation, since myofibroblasts have been demonstrated in a number of fibroblastic [14-161 and fibrous histiocytic tumors [14]. This has given rise to the concept that there exists a spectrum of tumors with a common mesenchymal stem cell and a range of specialization that includes fibroblastic, myogenic and histiocytic differentiation [14,16]. Experience with soft tissue fibrosarcomas indicates that histologic differentiation or grading is a useful prognostic indicator [1,2,17]. Poorly differentiated tumors have a 5 year survival significantly lower than the 60 percent overall average for all grades [2,17]. An increase in survival after radical surgery as opposed to simple local excision has been noted [1,2,17]. The difficulty with which this is achieved in primary, solid omental sarcomas probably accounts to some extent for their highly lethal behavior [5,8]. From these observations it is difficult to predict the biologic behavior in this particular case. Although of a histologically high grade, the singular lack of infiltration, restricted blood supply and ease of total excision should reduce the risk of local recurrence and blood-borne metastasis. Nevertheless, the anaplsstic nature of this tumor dictates a guarded prognosis, and a 12 month course of adjuvant chemotherapy with Adriamycin@, cytotoxin and dimethyltriazenoimidazole carboxamide (DTIC) is planned.
[5,7,81.
It is difficult to reconcile the gross configuration of this tumor with its aggressive histologic appearance. An encapsulated, noninvasive, pedunculated mass of this nature is far more likely to arise as a re460
Summary A 50 year old man presented with lower abdominal pain and hypotension of sudden onset. Emergency The American Journal of Surgery
PeduncuiatedFibrosarcoma
laparotomy for a suspected ruptured abdominal aortic aneurysm revealed the source of hemorrhage to be a ruptured vessel in the vascular pedicle of a large, oval tumor. This tumor had a unique appearance, lying virtually free within the abdominal cavity except for a 17 cm long umbilical cord-like vascular attachment to the greater omentum and a single fibrous adhesion to the anterior abdominal wall. Histologic examination disclosed the features of fibrosarcoma with a prominent population of myofibroblasts. Review of the literature yielded no previous examples of a similar pedunculated fibrosarcoma. References Bizer LS. Fibrosarcoma: report of sixty-four cases. Am J Surg 1971;588:121. Pritchard [XI, Soule ES, Taylor WF, lvins JC. Fibrosarcoma: a ciinicopathologic and statistical study of 199 tumors of the soft tissues of the extremities and trunk. Cancer 1974;33: 888. Heath AO, Wagern FB. Retroperitoneai fibrosarcoma. Arch Surg 1966;92:198. Heller EL, Sieber WK. Fibrosarcoma: a clinical and pathological study of 60 cases. Surgery 1950;27:539.
Volume 140,8uptem&
1990
5 Stout AP. Hendry J, &die FJ. Primary solid tumors of the greater omentum. Cancer 1963;16:231. 6. Pugh Ji. Mesocollc fibrosarcoma. Br J Surg 1960;47:526. 7. Turcinen M, Eifving G. Primary sarcoma of the omentum. Acta Chir Stand 1957;112:110. 8. Elfving G. Hastbacka J. Primary solid tumors of the greater omentum. Acta Chir Stand 1965;130:803. 9. Norman FW. Fibrous tumors of the omentum. Calif Med 1983;99:407. 10. Smith HF. Peritoneal fibromatosis presenting as an acute abdominal emergency. Br J Surg 1960;48: 161. 11. Demopoulos RI. Benign lesions of ths myometrium. in: Blausteln A, ed. Pathology of the female genital tract. New York: Springer-Verlag, 1977:300. 12. Rudolph R, Guber S, Suzuki M, Woodward M. The life cycle of the myofibroblast. Surg Gynecol Obstet 1977;145:389. 13. Ryan GB, Cliff WJ, Gabbiani G, et ai. Myofibroblasts in human granulation tissue. Hum Pathol 1974;5:55. 14. Churg AM, Kahn LB. Myofibroblasts and related cells in malignant fibrous and fibrohistiocytic tumors. Hum Pathoi 1977;8:205. 15. Cracker DJ, Murad TM. Ultrastructure of fibrosarccma in a male breast. Cancer 1969;23:891. 16. Vasudev KS, Harris M. A sarcoma of myofibroblasts: an ultrastructural study. Arch Pathoi Lab Med 1978;102:185. 17. Pritchard DJ, Sim FH, ivins JC, Dahlin DC. Symposium on tumors of the musculosketai system: fibrosarcoma of bone and soft tissues of the trunk and extremities. in: Moore TM, ed. orthopedic clinics of North America. Vol8. Philadelphia: WB Saunders, 1977:869-81.
461
Pedunculated Fibrosarcoma Unusual Presentation of an lntraabdominal Fibrosarcoma Arising From the Greater Omentum
Stanley Lipper, MD, Chapel Hill, North Carolina Edwin W. Nunnery, MD, Chapel Hill, North Carolina Kent L. Jones, MD, Chapel Hill, North Carolina
The vast majority of fibrosarcomas occur in external soft tissues [I ,2]. Primary intraabdominal examples are uncommon and have been described in the viscera [I], retroperitoneum [1,3-51, mesentery [6] and omentum [5,7,8]. Although partially encapsulated, these tumors invariably infiltrate surrounding structures, which contributes to their overall dismal prognosis [1,5,7]. We could find no reported case in which a fibrosarcoma clinically mimicking a ruptured abdominal aortic aneurysm, manifested as a virtually free-lying tumor attached to its parent omentum by a long, fibrovascular, cord-like pedicle. We therefore report this highly unusual case with light microscopic and ultrastructural observations. Case Report A 50 year old black man was in good health until he presented to his home town hospital emergency room in shock after the sudden onset of severe lower abdominal pain on the morning of admission. His blood pressure was 70/40 mm Hg and pulse 120 beats/min. Special investigations revealed a hemoglobin of 13 g/100 ml, a hematocrit of 39 percent and a white cell count of 10,800/mm3. Intravenous infusion of 1 liter of Ringer’s lactate raised the blood pressure to 110/80 mm Hg. Physical examination disclosed a large, tender, pulsatile abdominal mass. Abdominal roentgenography, including intravenous pyelography, showed superior and lateral displacement of the bowel by
a large lower abdominal mass which indented the dome of the bladder. The patient was transferred to North Carolina Memorial Hospital, where a tentative diagnosis of ruptured aortic aneurysm was made. At celiotomy a large, mobile, encapsulated mass was found (Figure 1). The tumor was suspended from the gastric omentum by an umbilical cord-like vascular pedicle 17 cm long. The source of hemorrhage was a ruptured vein at the lower end of the vascular pedicle. Delivery of the tumor was accomplished easily by resecting the omental origin of the cord and transecting a fibrous adhesion between the tumor capsule and the lower anterior abdominal wall. Tissue excised from the latter attachment site was considered on frozen-section analysis to be free of tumor. There was no evidence of intraabdominal spread of disease. The postoperative recovery was uneventful. Material
and Methods
Tissue for light microscopy was fixed in 10 percent formaldehyde solution and cut into paraffin sections. The stains used included hematoxylin-eosin and Weigert’s reticulin stain. Fresh minced tissue was fixed in phosphatebuffered, 4 percent paraformaldehyde, washed in a 0.1 M phosphate buffer and postfixed in phosphate buffered, 2 percent osmic acid. After dehydration in graded ethanol, the tissue was cleared with propylene oxide. Sections were stained with uranyl acetate and lead citrate and examined under a JEOL-JEM T7 electron microscope. Results
From the Departments of Surgical Pathology and Surgery, School of Medicine, University of North Carolina, Chapel Hill, North Carolina. Requests for reprints should be addressed to Stanley Lipper, MD, Department of Pathology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27514.
Volume 140, September 1990
Macroscopic findings: The specimen consisted of a firm, oval mass measuring 17 by 12 by 9 cm, with a smooth-surfaced, bosselated contour and a thin
457
Lipper et al
fibrous capsule (Figure 1). A 17 cm long, cord-like leash of tortuous blood vessels embedded in fibrofatty tissue inserted into the upper capsular surface through a fibrous, mesentery-like expansion. The proximal end of this cord merged with lobules of omental fat. A thin, transected fibrous adhesion was present anteriorly. The cut surface revealed a solid tumor composed of tan- to gray-colored, irregular nodules with intervening areas of hemorrhage, necrosis and cyst formation (Figure 2). A separate piece of tissue representing the excised abdominal wall attachment of the adhesion was also submitted. Microscopic findings: Sections showed the features of a fibroscarcoma with varying degrees of differentiation, ranging from moderately differen-
tiated regions composed of fusiform cells arranged in a fasciculated pattern and associated with bands of collagen and abundant reticulin, to predominantly poorly differentiated areas consisting of plump, spindle to round cells forming solid sheets devoid of reticulin (Figures 3 and 4). Mitoses were present in all areas and exceeded 40 per 10 high power fields in the most cellular and anaplastic fields. Areas of necrosis and myxoid degeneration were present. The cord structure consisted of large arteries and veins embedded in fibrofatty tissue. No tumor was identified in this tissue. The fibrous adhesion consisted of loose fibrovascular tissue and an active fibroblastic
Figure 1. Operative photograph of the tumor showing the umbilical. cord-like vascular pedicie ( shori arrow) arklng from the greater omentum and insertkg into the tumor. 77~9 clamped fibrous adhesion between the tumor and the anterior abdominal wall is also she wn ( long arrow ) .
Figure 2. Cut surface of tumor composed of tan to gray nodules w/th lntervenkg hemorrhage, necmsk and cysts.
450
F&sw 3. A, fasckks of ks/krm celk associated with bamts of collagen and retkulin. ( Hematoxylk-eosk stain; magnifkatkn X100, reduced 26 percent.) 6, retkulln stain hlghMghtkg fasckulated pattern. ( Welgert’s stain; magnifkation X100, reduced 26 percent.)
The American Journal of Surgewy
Pedunculated Fibrosarcoma
component tumor.
which lacked the cellular atypia of the
Electron microscopy: The area selected for electron microscopy consisted of closely packed, round to oval cells with a few elongated forms (Figure 5). Relatively few collagen fibers, mostly nonpolymerized, were present in the intercellular spaces
Figure 4. Poorly differentiated area composed of plump spindie ceils with frequent mitoses. inset, cellular field of round ceils in solid sheet. ( Hematoxyiin-eosin stain; magn/f/cation X200, reduced 26 percent.)
F&s-e 5. Cioseiy packed round to oval ceil with occasional elongated form; prominent rough endopiasmic reticulum is shown. (&any/ acetate and lead citrate stain; magnificatkn X4,920, reduced 46 percent. )
Volume 140, September lQQ0
(Figure 6). The nuclei showed heterochromatin clumping, with conspicuous perichromatin granules (Figure 7). The cytoplasm of many cells contained prominent rough endoplasmic reticulum (Figure 5). A striking feature was the presence of varying numbers of fine cytoplasmic filaments in many of the cells. These filaments were sometimes so numerous
Figure 6. Intercellular, nonpolymerized collagen fibers; adbcent ceil wntains psripherai myoftiaments with a dense body (long arrow), pinocytotic vesicle ( curved arrow), InteuWWu j &p&g ceil process (short arrow) and plasma membrane plaque (slanted arrow). (Uranyi acetate and lead citrate stain; magnification X23,760, reduced 46 percent. )
Figure 7. Dense aggregates of cytoplasm/c filaments; prominent perichromatin granules are present (uranyi acetate and lead citrate stain; magnifkatkn X&?,SgO,reduced 46 percent). inset, detail of perichromatin granules ( magnification X78,100).
459
Lipper et al
Figure 8. Peripherally arranged myofifaments with dense body condensation ( uranyl acetate and lead c/&ate stain; magnifkation X3 1,320, reduced 46 percent). Inset, detail of dense bodies near plasma membrane (magnification X62,460).
that they filled the cytoplasm (Figure 7). More often, they were sparse and arranged peripherally (Figures 6 and 8). Areas of dense body condensation were occasionally seen along the lengths of these filaments (Figure 8). Several intercellular junction attachments were present as well as a few plasma membrane plaques (Figure 6). Rare pinocytotic vesicles were identified (Figure 6). There was no evidence of basement membrane formation. Comments Fibrosarcomas are relatively common tumors of the soft tissues of the extremities and trunk [1,2]. The rare cases of primary intraabdominal neoplasms occur as infiltrative lesions arising in the viscera 111, retroperitoneum [1,3-S], mesocolon [6] and greater omentum [5,7,8]. The present case represents a unique example of a fibrosarcoma attached to its parent structure, the greater omentum, by a long vascular pedicle. We could find no precedent for a pedunculated fibrosarcoma in the literature, although there are several descriptions of primary, solid, invasive fibrosarcomas of the greater omentum
sult of a long-standing benign process such as occurs in the extremely rare cases of multiple benign pedunculated fibrous tumors of the omentum [9] and peritoneum [IO] and in the commonly occurring pendunculated, subserosal uterine leiomyomata VII. The better-differentiated areas of this tumor permitted a confident histologic interpretation of fibrosarcoma based on identification of the typical fasciculated, collagen- and reticulin-rich fusiform cell areas, in contrast to the poorly differentiated, solid areas devoid of reticulin. Ultrastructural examination of tissue representative of the latter component disclosed a population of cells with the characteristic features of myofibroblasts, with myofilaments occurring both as large aggregates in some cells and as peripherally arranged parallel bundles in others. These peripheral bundles sometimes showed dense body condensations close to the plasma membrane. Rare attachment plaques were present along cell membranes [12,13]. Myogenous differentiation in tumors other than those of pure smooth muscle derivation is now an established ultrastructural observation, since myofibroblasts have been demonstrated in a number of fibroblastic [14-161 and fibrous histiocytic tumors [14]. This has given rise to the concept that there exists a spectrum of tumors with a common mesenchymal stem cell and a range of specialization that includes fibroblastic, myogenic and histiocytic differentiation [14,16]. Experience with soft tissue fibrosarcomas indicates that histologic differentiation or grading is a useful prognostic indicator [1,2,17]. Poorly differentiated tumors have a 5 year survival significantly lower than the 60 percent overall average for all grades [2,17]. An increase in survival after radical surgery as opposed to simple local excision has been noted [1,2,17]. The difficulty with which this is achieved in primary, solid omental sarcomas probably accounts to some extent for their highly lethal behavior [5,8]. From these observations it is difficult to predict the biologic behavior in this particular case. Although of a histologically high grade, the singular lack of infiltration, restricted blood supply and ease of total excision should reduce the risk of local recurrence and blood-borne metastasis. Nevertheless, the anaplsstic nature of this tumor dictates a guarded prognosis, and a 12 month course of adjuvant chemotherapy with Adriamycin@, cytotoxin and dimethyltriazenoimidazole carboxamide (DTIC) is planned.
[5,7,81.
It is difficult to reconcile the gross configuration of this tumor with its aggressive histologic appearance. An encapsulated, noninvasive, pedunculated mass of this nature is far more likely to arise as a re460
Summary A 50 year old man presented with lower abdominal pain and hypotension of sudden onset. Emergency The American Journal of Surgery
PeduncuiatedFibrosarcoma
laparotomy for a suspected ruptured abdominal aortic aneurysm revealed the source of hemorrhage to be a ruptured vessel in the vascular pedicle of a large, oval tumor. This tumor had a unique appearance, lying virtually free within the abdominal cavity except for a 17 cm long umbilical cord-like vascular attachment to the greater omentum and a single fibrous adhesion to the anterior abdominal wall. Histologic examination disclosed the features of fibrosarcoma with a prominent population of myofibroblasts. Review of the literature yielded no previous examples of a similar pedunculated fibrosarcoma. References Bizer LS. Fibrosarcoma: report of sixty-four cases. Am J Surg 1971;588:121. Pritchard [XI, Soule ES, Taylor WF, lvins JC. Fibrosarcoma: a ciinicopathologic and statistical study of 199 tumors of the soft tissues of the extremities and trunk. Cancer 1974;33: 888. Heath AO, Wagern FB. Retroperitoneai fibrosarcoma. Arch Surg 1966;92:198. Heller EL, Sieber WK. Fibrosarcoma: a clinical and pathological study of 60 cases. Surgery 1950;27:539.
Volume 140,8uptem&
1990
5 Stout AP. Hendry J, &die FJ. Primary solid tumors of the greater omentum. Cancer 1963;16:231. 6. Pugh Ji. Mesocollc fibrosarcoma. Br J Surg 1960;47:526. 7. Turcinen M, Eifving G. Primary sarcoma of the omentum. Acta Chir Stand 1957;112:110. 8. Elfving G. Hastbacka J. Primary solid tumors of the greater omentum. Acta Chir Stand 1965;130:803. 9. Norman FW. Fibrous tumors of the omentum. Calif Med 1983;99:407. 10. Smith HF. Peritoneal fibromatosis presenting as an acute abdominal emergency. Br J Surg 1960;48: 161. 11. Demopoulos RI. Benign lesions of ths myometrium. in: Blausteln A, ed. Pathology of the female genital tract. New York: Springer-Verlag, 1977:300. 12. Rudolph R, Guber S, Suzuki M, Woodward M. The life cycle of the myofibroblast. Surg Gynecol Obstet 1977;145:389. 13. Ryan GB, Cliff WJ, Gabbiani G, et ai. Myofibroblasts in human granulation tissue. Hum Pathol 1974;5:55. 14. Churg AM, Kahn LB. Myofibroblasts and related cells in malignant fibrous and fibrohistiocytic tumors. Hum Pathoi 1977;8:205. 15. Cracker DJ, Murad TM. Ultrastructure of fibrosarccma in a male breast. Cancer 1969;23:891. 16. Vasudev KS, Harris M. A sarcoma of myofibroblasts: an ultrastructural study. Arch Pathoi Lab Med 1978;102:185. 17. Pritchard DJ, Sim FH, ivins JC, Dahlin DC. Symposium on tumors of the musculosketai system: fibrosarcoma of bone and soft tissues of the trunk and extremities. in: Moore TM, ed. orthopedic clinics of North America. Vol8. Philadelphia: WB Saunders, 1977:869-81.
461