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Pediatric sacrococcygeal chordomas: A rare tumor to be differentiated from sacrococcygeal teratoma
Pediatric Sacrococcygeal Chordomas: A Rare Tumor to be Differentiated From Sacrococcygeal By David
G. Cable and Christopher Rochester, Minnesota
l Sacrococcygeal chordoma is a rare pediatric neoplasm that may be confused with the more common, and indolent, teratoma. The present report describes the diagnosis, treatment and early postoperative convalescence of a case of chordoma in an adolescent child. This case is contrasted to the sacrococcygeal teratoma, a familiar pediatric neoplasm, and the literature is reviewed with respect to presentation and treatment. Copyright D 1997 by W.B. Saunders Company INDEX
WORDS:
Sacrococcyeal
chordoma,
sacral
tumors.
ACROCOCCYGEAL CHORDOMA is a relatively rare but highly lethal neoplasm derived from remnants of the primitive notochord. The notochord regresses during normal development except as a constituent of the nucleus pulposus in the intervertebral disc.’ Malignant degeneration of notochordal elements form a primitive neurogenic tumor known as chordoma. These unusual pediatric neurogenic tumors have a predilection for the clivus and sacrococcygeal locations. Sacrococcygeal chordomas comprise 52% to 65% of published series of chordomas in general,2-5which are clinically and histologically distinct from the more familiar sacrococcygeal teratoma. However, the aggressive disposition of chordomas require the pediatric surgeon to retain this tumor within the differential diagnosis of sacrococcygeal masses. The first description of notochordal remnants is attributed to Luschka in 1856.6 Later, Muller suggested the neoplasm may be a descendent of the notochord. Ribbert named the neoplasm in 1894.7 In 1925, Coenen classified chordomas based on location within the cerebrospinal axis. A total of 253 cases were described in a report published in 1944.* Approximately 700 cases have been described in the world literature.4 The incidence of chordomas in the pediatric population is reduced by an order of magnitude. In 1926, Argand and Lestrade published the description of a 14-month-old girl with a sacrococcygeal chordoma.9 Less that 5% of reported cases, both cranial and axial skeleton, arise within the first two decades of life.‘O Only 18 cases of sacrococcygeal chordomas have been described to occur inside 20 years of age. 11-i3 Because of the sporadic reporting of this tumor, this is certainly an underrepresentation of the incidence. The differential diagnosis of sacrococcygeal masses includes over 50 lesions. I4 Sacrococcygeal teratomas are well recognized in infants and exhibit an initially more indolent course. The lethal malignant potential of childhood chordomas carries specific management concerns S
Journal
ofPediatm
Surgery,
Vol32,
No 5 (May),
1997: pp 759-761
Teratoma
Moir
beyond those of a sacrococcygeal teratoma, but the rarity of chordomas in the pediatric population has hampered professional appreciation of this lesion. On average, 2 years elapse between symptom onset and diagnosis. Because surgical excision is the prime determinant of outcome, the purpose of this paper is to document another case that is tragically typical of the long delay in diagnosis from symptom onset. The ensuing operative procedure was heroic but debilitating to attempting a cure. The thorough evaluation of persistent pain in the older child may help uncover tumors such as chordomas at an earlier more curative stage. CASE
REPORT
A 12-year-old girl presented to her local physician complaining of low lumbar and sacral pain of undetermmed duration, Findings durmg physical examination. includmg rectal examination. were normal. A plam abdominal film and pelvic roentgenogram were obtamed and were also normal. She presented again 2 months later for a routine school physical exammation where no abnormalities were noted. One year later. the patient’s mother noted a mass in the buttocks region, Evaluation confirmed the lumbar and sacral pain was persistent and the mtensity was similar to the previous year. Rectal exammatlon at this time showed a palpable mass. Abdominal and pelvic computed tomography (CT) demonstrated that a large pelvic mass eroded the coccyx and displaced the uterus and rectum. On presentation to our institution. the lumbar and sacral pam was characterized as a dull, constant aching An associated 10 to 15 pound weight loss was noted during the previous year. The patient reported no gastrointestinal, urinary, or neurological symptomatology. The patient had a past medical history remarkable only for a right upper extremity fracture and acne vulgaris. The family medical history was remarkable for a deceased grandparent secondary to ovarian carcmoma. Physical examination noted a well-nourished girl of 43.4 kg and 154 cm. Spmal examination showed a 7- X 9-cm firm mass overlying the sacralcoccygeal region. The mass was slightly tender to moderate palpation. There was no overlying skin abnormalities or discoloration, Abdommal examination showed a soft, nondistended, and nontender abdomen without palpable masses or organomegaly. Rectal examination showed a firm, nonmobile mass. Neurological testing results were normal. Abdominal and pelvic CT scan was obtained to provide a tissue diagnosis. Imaging confirmed a 9-cm mass arising from an eroded coccyx. The lobulated mass was noted to contain internal septations and calcifications. In addition, the mass was noted to be m continuity with both gluteal maximus muscles and to displace both the rectum and sigmoid colon anteriorly. CT-guided needle biopsy results characterized
From the Department of Surgery, Mayo Clinic and Mayo Foundation, Rochestel; MN. Address reprmt requests to Christopher R Moz1; MD, 200 First Street, SW Rochestel; MN 55905. Copyright o 1997 by WB. Saunders Company 0022-3468/97/3205-0028$03.00/O 759
CABLE
760 a chordoma. Magnetic resonance imaging was also used to delineate mvolvement of the nervous system. The third sacral roots were noted to be free of involvement. However, all distal spinal roots were engulfed by the mass. A complete blood count, electrolyte panel, chemistry profile, and urinary metanephrines were within normal ranges. A team composed of pediatrrc, neurologic. and orthopedic surgeons performed the tumor excision. A low transverse Phannenstiel incision was performed. The tumor was mobilized by division of the rectal peritoneal reflections. ligation of presacral vessels. and dissection from the left obturator foramen. Dtssedtion was continued to the junction of the second and third sacral vetrebrae. On completion of circumferential dissection, the peritoneal defect was primarily closed and the abdominal wall closed in layers. The patient was placed in the prone position. A transverse curvilinear incision was performed, similar to sacrococcygeal teratoma resection. Proximal and distal flaps were generated. The sacrum was transected with a reciprocating saw, sacrificing S2 and S3 nerve roots for en bloc excision. Preliminary pathology confirmed the diagnosis of chordoma with positive resection margins. Subsequently, extended muscular excision was performed to obtain margins free of tumor involvement. A total of 5 U packed red blood cells and 2 U of fresh frozen plasma was infused during the procedure. Final pathology testmg showed a 13.5- X 9.3- X 8.5-cm chordoma centered symmetrrtally on the sacmm. The sacrum had subtotal destruction of the central portion. No vascular or lymphatic invasions were identrfied. The patient had a stable postoperative convalensce. The patient remained in a prone position through postoperative day 3. and was discharged home on postoperative day 7. The patient was evaluated in the clinic 6 months after tumor excision. She had returned to an acttve lifestyle. Urinary retention with postvoid residuals between 100 and 400 mL necessitated intermittent, clean catherization. However, no urinary tract infections or incontmence were noted. She reported fecal incontinence associated with a deficiency of rectal sensation. This was treated with aggressive bowel regimens to facilitate colonic emptying in the early evening
DISCUSSION
Chordomas represent 1% to 4% of primary neoplasms of the bone. Dahlin et al3 published the finding of 4,774 primary bone neoplasms treated at the Mayo Clinic. Only 195 of these cases proved to be chordomas, representing 3.1% of the total patients. Although 52% to 65% of all chordoma cases in published reports arise within the sacrococcygeal location, appearance in this location is exceedingly rare during the first two decades of life. The present case represents only the 19th described sacrococcygeal chordoma found in the world literature since the recognition of this neoplasm.11-13 Presentation As in the current case, pain is the chief presenting complaint of patients with sacrococcygeal chordomas. In the pediatric series, the mean duration of symptoms before presentation was 2 years, our case being representative of the average. Constipation is the next most frequently reported symptom. A presacral mass, perianal anesthesia, lower extremity paresthesias, neurogenic bladder dysfunction, and fecal incontinence have all been described. Rectal examination shows a palpable retrosacral mass in greater than 90% of cases reported. I4 Less commonly,
AND
MOIR
sensory deficits and gross lower extremity muscle deterioration have been documented with examination. Routine laboratory screening seldom generates an abnormality. However, an anemia secondary to chronic disease is occasionally isolated.15 In addition, mild elevations in alkaline phosphatase level and sedimentation rate have been described. Radiographically, chordomas are considered to have four pathognomic characteristics on plain film evaluation: expansion of bone, rarefaction, trabeculation, and calcification.16 CT scan has been shown to improve diagnosis in retrospective analysis. In particular, CT imaging improved delineation of soft tissue mass and calcific debris. In the past, angiography and myelography have been used. Currently, neither modality provides improved diagnostic capabilities. Treatment Surgical resection en bloc is the treatment of choice. MacCarty et al3 in 1956 described the removal of the distal three sacral segments and coccyx with preservation of the pudendal nerves and proximal three sacral nerves. At present, the literature supports a combined team approach with pediatric surgery, orthopedic surgery, and neurosurgery based on the principles of MacCarty. Because many surgical interventions have produced positive tumor margins in an attempt to preserve postoperative neural function, external beam radiotherapy has been widely used. Chordomas have the reputation of being particularly “radioresistant.” However, patients who receive postoperative radical radiotherapy may achieve longer survival and palliation.17 Chemotherapy has been described anecdotally within the literature. The formation of a chemotherapeutic regimen is primarily based around vincristine. The utility of chemotherapy has not been confidently established. Outcomes Mean postoperative survival is approximately 50 to 60 months.r6 The 5-year survival rate is between 10% and 30%.16 However, these survival curves are based on the few large series within the adult population. Chordomas within the pediatric population may represent a more aggressive variant. l* The incidence of metastasis varies between 10% and 40%. Metastases are usually seen in the lungs, viscera, liver, and muscle. This case illustrates a sacrococcygeal lesion arising remote from infancy, in contradistinction to teratomas. The principle of thorough evaluation of adolescent somatic complaints would have allowed early diagnosis, improved surgical resection, and possibly, improved prognosis. Because this aggressive tumor is insensitive to radiation and chemotherapy, surgical resection is the only chance for cure.
SACROCOCCYGEAL
761
CHORDOMA
REFERENCES 1. Pazzaglia UE, Salisbury JR, Byers PD. Development and mvolution of the notochord in the human spine. J R Sot Med 82:413-415, 1989 2. Volpe R, Mazabraud A: A climpathologic review of 25 cases of chordoma Am .I Surg Path 7:161-170. 1983 3 Dahlin DC, MacCarty CS: Chordoma: A study of fifty-nine cases. Cancer 6:1170-1178, 1952 4. Eriksson B. Gunterber G. Kindblom L: Chordoma: Aclinicopathologic and prognostic study of a Swedish national series. Acta Orthop Stand 52:49-58, 1981 5. Highinbotham NL, Phillips RF, Farr HW, et al: Chordoma: Thirty-five year study at Memorial Hospital. Cancer 20:1841-1850, 1967 6. Luschka H. Dte Altersveranderungen der Zwichenwirbelknorpel. Virchows ArchA 9:311-327, 1856 7. Ribbert H: Uber die Ecchondrosis physalifora sphenooccrpitahs. Zbl Allg Path Anat 5:457-461. 1894 8. Faust DB, Gtlmore HR. Jr, Mudgett S: Chordomata: A review of the literature, with report of a Sacrococcygeal case. Ann Int Med 21:678-698, 1944 9. Argand R, Lestrade A: Chordoma in an infant (abstract). JAMA 86:1731. 1926
10. Wold LE, Laws ER Jr: Cranial chordomas m children and young adults. J Neurosurg 59:1043-1047. 1983 11. Richards AT. Strtckle L, Spitz L: Saccrococcygeal chordomas in children. J Pediatr Surg 8:911-913, 1973 12. Nix WL, Steuber CP, Hawkins EP, et al: Sacrococcygeal chordoma in a neonate with multiple anomalies. J Pediatr 93.995-998. 1978 13. Koslowski K. Barylak A. Campbell J, et al: Primary sacral bone tumors m children: Report of 16 cases with a short literature revtew. Austral Radio1 34: 142-149, 1990 14 Lemir RJ, Beckwnb JB: Pathogenesis of congenital tumors and malformations of the sacrococcygeal regton. Teratology 25:201-213, 1982 15. Kaiser TE. Pritchard DJ, Unni KK: Clinicopathologic study of sacrococcygeal chordomas. Cancer 54:2574-2578, 1984 16. Swinton NW, Lehman G: Presacral tumors. Surg Clin North Am 6:849-852,
1958
17. Chetiyawardana AD: Chordoma: Results of treatment. Clin Radio1 35:159-161, 1984 18. Coffin CM, Swanson PE, Wick MR. et al: Chordoma in chtldhood and adolescence: A climcopathologic analysis of 12 cases. ArchPathol LabMed 117:927-933, 1993
G. Cable and Christopher Rochester, Minnesota
l Sacrococcygeal chordoma is a rare pediatric neoplasm that may be confused with the more common, and indolent, teratoma. The present report describes the diagnosis, treatment and early postoperative convalescence of a case of chordoma in an adolescent child. This case is contrasted to the sacrococcygeal teratoma, a familiar pediatric neoplasm, and the literature is reviewed with respect to presentation and treatment. Copyright D 1997 by W.B. Saunders Company INDEX
WORDS:
Sacrococcyeal
chordoma,
sacral
tumors.
ACROCOCCYGEAL CHORDOMA is a relatively rare but highly lethal neoplasm derived from remnants of the primitive notochord. The notochord regresses during normal development except as a constituent of the nucleus pulposus in the intervertebral disc.’ Malignant degeneration of notochordal elements form a primitive neurogenic tumor known as chordoma. These unusual pediatric neurogenic tumors have a predilection for the clivus and sacrococcygeal locations. Sacrococcygeal chordomas comprise 52% to 65% of published series of chordomas in general,2-5which are clinically and histologically distinct from the more familiar sacrococcygeal teratoma. However, the aggressive disposition of chordomas require the pediatric surgeon to retain this tumor within the differential diagnosis of sacrococcygeal masses. The first description of notochordal remnants is attributed to Luschka in 1856.6 Later, Muller suggested the neoplasm may be a descendent of the notochord. Ribbert named the neoplasm in 1894.7 In 1925, Coenen classified chordomas based on location within the cerebrospinal axis. A total of 253 cases were described in a report published in 1944.* Approximately 700 cases have been described in the world literature.4 The incidence of chordomas in the pediatric population is reduced by an order of magnitude. In 1926, Argand and Lestrade published the description of a 14-month-old girl with a sacrococcygeal chordoma.9 Less that 5% of reported cases, both cranial and axial skeleton, arise within the first two decades of life.‘O Only 18 cases of sacrococcygeal chordomas have been described to occur inside 20 years of age. 11-i3 Because of the sporadic reporting of this tumor, this is certainly an underrepresentation of the incidence. The differential diagnosis of sacrococcygeal masses includes over 50 lesions. I4 Sacrococcygeal teratomas are well recognized in infants and exhibit an initially more indolent course. The lethal malignant potential of childhood chordomas carries specific management concerns S
Journal
ofPediatm
Surgery,
Vol32,
No 5 (May),
1997: pp 759-761
Teratoma
Moir
beyond those of a sacrococcygeal teratoma, but the rarity of chordomas in the pediatric population has hampered professional appreciation of this lesion. On average, 2 years elapse between symptom onset and diagnosis. Because surgical excision is the prime determinant of outcome, the purpose of this paper is to document another case that is tragically typical of the long delay in diagnosis from symptom onset. The ensuing operative procedure was heroic but debilitating to attempting a cure. The thorough evaluation of persistent pain in the older child may help uncover tumors such as chordomas at an earlier more curative stage. CASE
REPORT
A 12-year-old girl presented to her local physician complaining of low lumbar and sacral pain of undetermmed duration, Findings durmg physical examination. includmg rectal examination. were normal. A plam abdominal film and pelvic roentgenogram were obtamed and were also normal. She presented again 2 months later for a routine school physical exammation where no abnormalities were noted. One year later. the patient’s mother noted a mass in the buttocks region, Evaluation confirmed the lumbar and sacral pain was persistent and the mtensity was similar to the previous year. Rectal exammatlon at this time showed a palpable mass. Abdominal and pelvic computed tomography (CT) demonstrated that a large pelvic mass eroded the coccyx and displaced the uterus and rectum. On presentation to our institution. the lumbar and sacral pam was characterized as a dull, constant aching An associated 10 to 15 pound weight loss was noted during the previous year. The patient reported no gastrointestinal, urinary, or neurological symptomatology. The patient had a past medical history remarkable only for a right upper extremity fracture and acne vulgaris. The family medical history was remarkable for a deceased grandparent secondary to ovarian carcmoma. Physical examination noted a well-nourished girl of 43.4 kg and 154 cm. Spmal examination showed a 7- X 9-cm firm mass overlying the sacralcoccygeal region. The mass was slightly tender to moderate palpation. There was no overlying skin abnormalities or discoloration, Abdommal examination showed a soft, nondistended, and nontender abdomen without palpable masses or organomegaly. Rectal examination showed a firm, nonmobile mass. Neurological testing results were normal. Abdominal and pelvic CT scan was obtained to provide a tissue diagnosis. Imaging confirmed a 9-cm mass arising from an eroded coccyx. The lobulated mass was noted to contain internal septations and calcifications. In addition, the mass was noted to be m continuity with both gluteal maximus muscles and to displace both the rectum and sigmoid colon anteriorly. CT-guided needle biopsy results characterized
From the Department of Surgery, Mayo Clinic and Mayo Foundation, Rochestel; MN. Address reprmt requests to Christopher R Moz1; MD, 200 First Street, SW Rochestel; MN 55905. Copyright o 1997 by WB. Saunders Company 0022-3468/97/3205-0028$03.00/O 759
CABLE
760 a chordoma. Magnetic resonance imaging was also used to delineate mvolvement of the nervous system. The third sacral roots were noted to be free of involvement. However, all distal spinal roots were engulfed by the mass. A complete blood count, electrolyte panel, chemistry profile, and urinary metanephrines were within normal ranges. A team composed of pediatrrc, neurologic. and orthopedic surgeons performed the tumor excision. A low transverse Phannenstiel incision was performed. The tumor was mobilized by division of the rectal peritoneal reflections. ligation of presacral vessels. and dissection from the left obturator foramen. Dtssedtion was continued to the junction of the second and third sacral vetrebrae. On completion of circumferential dissection, the peritoneal defect was primarily closed and the abdominal wall closed in layers. The patient was placed in the prone position. A transverse curvilinear incision was performed, similar to sacrococcygeal teratoma resection. Proximal and distal flaps were generated. The sacrum was transected with a reciprocating saw, sacrificing S2 and S3 nerve roots for en bloc excision. Preliminary pathology confirmed the diagnosis of chordoma with positive resection margins. Subsequently, extended muscular excision was performed to obtain margins free of tumor involvement. A total of 5 U packed red blood cells and 2 U of fresh frozen plasma was infused during the procedure. Final pathology testmg showed a 13.5- X 9.3- X 8.5-cm chordoma centered symmetrrtally on the sacmm. The sacrum had subtotal destruction of the central portion. No vascular or lymphatic invasions were identrfied. The patient had a stable postoperative convalensce. The patient remained in a prone position through postoperative day 3. and was discharged home on postoperative day 7. The patient was evaluated in the clinic 6 months after tumor excision. She had returned to an acttve lifestyle. Urinary retention with postvoid residuals between 100 and 400 mL necessitated intermittent, clean catherization. However, no urinary tract infections or incontmence were noted. She reported fecal incontinence associated with a deficiency of rectal sensation. This was treated with aggressive bowel regimens to facilitate colonic emptying in the early evening
DISCUSSION
Chordomas represent 1% to 4% of primary neoplasms of the bone. Dahlin et al3 published the finding of 4,774 primary bone neoplasms treated at the Mayo Clinic. Only 195 of these cases proved to be chordomas, representing 3.1% of the total patients. Although 52% to 65% of all chordoma cases in published reports arise within the sacrococcygeal location, appearance in this location is exceedingly rare during the first two decades of life. The present case represents only the 19th described sacrococcygeal chordoma found in the world literature since the recognition of this neoplasm.11-13 Presentation As in the current case, pain is the chief presenting complaint of patients with sacrococcygeal chordomas. In the pediatric series, the mean duration of symptoms before presentation was 2 years, our case being representative of the average. Constipation is the next most frequently reported symptom. A presacral mass, perianal anesthesia, lower extremity paresthesias, neurogenic bladder dysfunction, and fecal incontinence have all been described. Rectal examination shows a palpable retrosacral mass in greater than 90% of cases reported. I4 Less commonly,
AND
MOIR
sensory deficits and gross lower extremity muscle deterioration have been documented with examination. Routine laboratory screening seldom generates an abnormality. However, an anemia secondary to chronic disease is occasionally isolated.15 In addition, mild elevations in alkaline phosphatase level and sedimentation rate have been described. Radiographically, chordomas are considered to have four pathognomic characteristics on plain film evaluation: expansion of bone, rarefaction, trabeculation, and calcification.16 CT scan has been shown to improve diagnosis in retrospective analysis. In particular, CT imaging improved delineation of soft tissue mass and calcific debris. In the past, angiography and myelography have been used. Currently, neither modality provides improved diagnostic capabilities. Treatment Surgical resection en bloc is the treatment of choice. MacCarty et al3 in 1956 described the removal of the distal three sacral segments and coccyx with preservation of the pudendal nerves and proximal three sacral nerves. At present, the literature supports a combined team approach with pediatric surgery, orthopedic surgery, and neurosurgery based on the principles of MacCarty. Because many surgical interventions have produced positive tumor margins in an attempt to preserve postoperative neural function, external beam radiotherapy has been widely used. Chordomas have the reputation of being particularly “radioresistant.” However, patients who receive postoperative radical radiotherapy may achieve longer survival and palliation.17 Chemotherapy has been described anecdotally within the literature. The formation of a chemotherapeutic regimen is primarily based around vincristine. The utility of chemotherapy has not been confidently established. Outcomes Mean postoperative survival is approximately 50 to 60 months.r6 The 5-year survival rate is between 10% and 30%.16 However, these survival curves are based on the few large series within the adult population. Chordomas within the pediatric population may represent a more aggressive variant. l* The incidence of metastasis varies between 10% and 40%. Metastases are usually seen in the lungs, viscera, liver, and muscle. This case illustrates a sacrococcygeal lesion arising remote from infancy, in contradistinction to teratomas. The principle of thorough evaluation of adolescent somatic complaints would have allowed early diagnosis, improved surgical resection, and possibly, improved prognosis. Because this aggressive tumor is insensitive to radiation and chemotherapy, surgical resection is the only chance for cure.
SACROCOCCYGEAL
761
CHORDOMA
REFERENCES 1. Pazzaglia UE, Salisbury JR, Byers PD. Development and mvolution of the notochord in the human spine. J R Sot Med 82:413-415, 1989 2. Volpe R, Mazabraud A: A climpathologic review of 25 cases of chordoma Am .I Surg Path 7:161-170. 1983 3 Dahlin DC, MacCarty CS: Chordoma: A study of fifty-nine cases. Cancer 6:1170-1178, 1952 4. Eriksson B. Gunterber G. Kindblom L: Chordoma: Aclinicopathologic and prognostic study of a Swedish national series. Acta Orthop Stand 52:49-58, 1981 5. Highinbotham NL, Phillips RF, Farr HW, et al: Chordoma: Thirty-five year study at Memorial Hospital. Cancer 20:1841-1850, 1967 6. Luschka H. Dte Altersveranderungen der Zwichenwirbelknorpel. Virchows ArchA 9:311-327, 1856 7. Ribbert H: Uber die Ecchondrosis physalifora sphenooccrpitahs. Zbl Allg Path Anat 5:457-461. 1894 8. Faust DB, Gtlmore HR. Jr, Mudgett S: Chordomata: A review of the literature, with report of a Sacrococcygeal case. Ann Int Med 21:678-698, 1944 9. Argand R, Lestrade A: Chordoma in an infant (abstract). JAMA 86:1731. 1926
10. Wold LE, Laws ER Jr: Cranial chordomas m children and young adults. J Neurosurg 59:1043-1047. 1983 11. Richards AT. Strtckle L, Spitz L: Saccrococcygeal chordomas in children. J Pediatr Surg 8:911-913, 1973 12. Nix WL, Steuber CP, Hawkins EP, et al: Sacrococcygeal chordoma in a neonate with multiple anomalies. J Pediatr 93.995-998. 1978 13. Koslowski K. Barylak A. Campbell J, et al: Primary sacral bone tumors m children: Report of 16 cases with a short literature revtew. Austral Radio1 34: 142-149, 1990 14 Lemir RJ, Beckwnb JB: Pathogenesis of congenital tumors and malformations of the sacrococcygeal regton. Teratology 25:201-213, 1982 15. Kaiser TE. Pritchard DJ, Unni KK: Clinicopathologic study of sacrococcygeal chordomas. Cancer 54:2574-2578, 1984 16. Swinton NW, Lehman G: Presacral tumors. Surg Clin North Am 6:849-852,
1958
17. Chetiyawardana AD: Chordoma: Results of treatment. Clin Radio1 35:159-161, 1984 18. Coffin CM, Swanson PE, Wick MR. et al: Chordoma in chtldhood and adolescence: A climcopathologic analysis of 12 cases. ArchPathol LabMed 117:927-933, 1993