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Extraspinal ependymoma
Extraspinal Ependymoma By S. Chou, P. Soucy, and B. Carpenter Ottawa, Ontario 9 T w o cases of extraspinal e p e n d y m o m a are described.
This is a low-grade t u m o r that recurs locally unless wide local excision is performed. It does metastasize, mainly to lymph nodes and lung. Its origin is likely from heterotopic ependymal cells called the coccygeal medullary vestige. 9 1987 by Grune & Stratton, Inc.
INDEX WORDS: Extraspinal ependymoma; sacrococcygeal tumor; ependymal rest.
H E R E HAVE BEEN two cases of extraspinal
ependymomas documented at the Children's T Hospital of Eastern Ontario. Both patients presented with a mass in the upper intergluteal fold. Pilonidal cyst was entertained in the differential diagnosis of both cases.
DISCUSSION
Extraspinal ependymomas occur in tWO characteristic locations: in the subcutaneous tissue posterior to the sacrum; and in the pelvis ventral to the sacrum in the retrorectal space. These tumors are primary to these extraspinal sites, and have no connection with the spinal cord. It is possible to have a primary intraspinal ependymoma erode through the sacrum and present as an extraspinal mass. z'2 A myelogram is recommended by some to rule out the more common ependymoma of the cauda equina) Extraspinal ependymomas are more common in children, 4 occurring as early as 2 months of age. ~ Patients with subcutaneous tumors present either with an asymptomatic mass, or a draining coccygeal sinus. 5 Ependymomas at this site compose up to 20% of
CASE REPORTS The first case is that of a 16-year-old girl who noticed a coccygeal mass following minor trauma. It remained asymptomatic and of the same size over the next 2 years. The mass was midline, 2 x 3 cm, and had a rubbery firm consistency. It did not have an external opening. The physical examination and investigations, including chest x-ray and x-rays of the lumbosacral spine, were normal except for the presence of spina bifida occulta at the level of S i. Intraoperatively, a nonencapsulated lesion was found, adherent to the dermis and completely free of the coccyx. The cut surface of the tumor was grayish-tan, with a few areas of hemorrhage. Grossly, it resembled neural tissue. Histology revealed a myxopapillary ependymoma, and due to the proximity of tumor infiltration to the line of resection, a wider excision was undertaken four days later. No residual tumor was found in the second specimen. The second case is that of a 9-year-old boy who had undergone an elective excision of a "pilonidal cyst." The skin overlying the mass was normal and had no external openings. The operative findings consisted of a well-localized tumor, lobulated, and thinly encapsulated. The diagnosis was a well-differentiated ependymoma. The lines of resection were free of tumor. T h e microscopy of the first case is shown in Fig 1. T h e tumor has an ill-defined capsule, with infiltration into the surrounding fibrofatty tissues. There are solid areas, and less cellular ones, where the cuboidal ependymal cells are arranged on fibrovascular stalks in a papillary configuration. Perivascular degeneration results in a myxold appearance, giving rise to pseudorosette formation.
From the Departnlent of Surgery, Children's Hospital of Eastern Ontario, Ottawa. Presented at the 18th Annual Meeting of the Canadian Association of Paediatric Surgeons. ttalifax, Nova Scotia, August 28-30, 1986. Address reprint requests to Pierre Soucy, MD, Children's Hospital of Eastern Ontario, 401 Snlyth Rd, Ottawa, Ontario, K I H 8LI Canada. 9 1987 by Grune & Stratton, Inc. 0022-3468/87/2209-0002503.00/0 802
Fig 1. Case 1. Myxopapillary ependymoma. The ependymal cells are arranged in a papillary configuration. Note also the areas of myxoid degeneration (H&E, x 110). Journal of Pediatric Surgery, Vo122, No 9 (September),1987: pp 802-803
EXTRASPINAL EPENDYMOMA
803
sacrococcygeal lesions in infants under 1 year of age. 5 Presacral ependymomas present predominantly with symptoms secondary to compression of surrounding structures. It makes up 2% to 1 1% of retrorectal tumors. 6 The embryologic basis for the origin of these tumors seems to be from coccygeal medullary vestige. 7 By the end of the third month of gestation, only a remnant of the caudal portion of the neural tube remains at the tip of the coccyx. This ependyma-lined cavity appears to have have pinched off from the neural tube and assumes an extramedullary and at times, even an extraspinal position) It is seen not only in embryos at the site of closure of the posterior neuropore (postanal pit), but according to Bale, also in over 50% of infants up to the age of 1 y e a r ) The coccygeal medullary vestige, therefore, may be the source of heterotopic ependymal cell rests. The incidence of associated spina bifida occulta varies from 20% to 30%. 1"2"7"93~Presence of such developmental failure demonstrates incomplete closure of the neural arch, enhancing the possibility of ependymal heterotopia. Presacral ependymomas a/'e postulated to arise either from the cauda equina, extending through the sacral foramina into the soft
tissues anteriorly, 6'H or from extradural remnants of the ilium terminale. 7 Extraspinal ependymoma is a slow growing lowgrade malignancy. Although the tumor poses problems mainly in local control, it m a y metastasize to regional lymph nodes, lung, bone, and liver. 7'~2 Adequate treatment consists of wide excision. Repeated excisions for local recurrences achieve good results) '7'~~.Bilateral inguinal node dissection is performed in the face of nodal metastasis. 7'13 Whether this improves survival is difficult to determine given the small number of patients in each series and the slow growing nature of the tumor. Indeed, survival of 10 to 20 years after diagnosis of the tumor has been reported. 7'8'~~Radiotherapy is reserved for residual or inoperable tumors. 2'3"6 Excision o f pulmonary metastasis is performed Where feasible. 7't~ In the face of widespread disease, the average postoperative survival is about 10 years) Chemotherapy does little to arrest the progression of disease) '6'~~ In conclusion, sacrococcygeal tumors, especially in infants and young children, should alert the surgeon to the possibility of extraspinal ependymoma, and merit further investigations and complete excision.
REFERENCES
1. Cooper IS, Winchell MC, Kernohan JW: Tumours of the spinal cord. Surg GynecolObstet 92:183-190, 1951 2. Anderson MS: Myxopapillaryependymomaspresenting in the soft tissue over the sacrococcygealregion. Cancer 19:585-590, 1966 3. Morantz RA, KepesJ J, Batnitzky S, et al: Extraspinal ependymomas. J Neurosurg 51:383-391, 1979 4. Bales PM: Saerococcygealdevelopmental abnormalities and tumors in children. Perspect Pediatr Pathol 1:9-56, 1984 5. Ciraldo AV, Platt MS, Agamanolis DP, et al: Sacrococcygeal myxopapillary ependymomasand ependymal rests in infants and children. J Pediatr Surg 21:49-52, 1986 6. Heath MH: Presacralependymoma.Am J Clin Patho139:161166, 1963 7. WolffM, Santiago H, Duby MM: Delayed distant metastasis from a subcutaneoussacrococcygealependymoma.Cancer 30:10461067, 1972
8. Bale PM: Ependymal rests and subcutaneous sacrococcygeal ependymoma. Pathology 12:237-243, 1980 9. Sawai M, Vyas J J, Talvalkar GV: Subcutaneous sacrococcygeal myxopapillaryependymoma.Ind J Cancer 15:72-73, 1978 10. Vagaiwala MR, Robinson JS, Galicich JH, et al: Metastasizing extradural ependymoma of the sacrococcygealregion. Cancer 44:326-333, 1979 1I. Gerston, KF, Suprun H, Cohen H, et al: Presacral myxopapillary ependymoma presenting as an abdominal mass in a child. J Pediatr Surg 20:276-278, 1985 12. Dormal P, Baye R: Ependymomesacro-coccygien.Acta Chir Belg 84:27-30, 1984 13. Hendren TH, Hardin CA: Extradural metastatic ependymoma. Surgery 54:880-882, 1963
This is a low-grade t u m o r that recurs locally unless wide local excision is performed. It does metastasize, mainly to lymph nodes and lung. Its origin is likely from heterotopic ependymal cells called the coccygeal medullary vestige. 9 1987 by Grune & Stratton, Inc.
INDEX WORDS: Extraspinal ependymoma; sacrococcygeal tumor; ependymal rest.
H E R E HAVE BEEN two cases of extraspinal
ependymomas documented at the Children's T Hospital of Eastern Ontario. Both patients presented with a mass in the upper intergluteal fold. Pilonidal cyst was entertained in the differential diagnosis of both cases.
DISCUSSION
Extraspinal ependymomas occur in tWO characteristic locations: in the subcutaneous tissue posterior to the sacrum; and in the pelvis ventral to the sacrum in the retrorectal space. These tumors are primary to these extraspinal sites, and have no connection with the spinal cord. It is possible to have a primary intraspinal ependymoma erode through the sacrum and present as an extraspinal mass. z'2 A myelogram is recommended by some to rule out the more common ependymoma of the cauda equina) Extraspinal ependymomas are more common in children, 4 occurring as early as 2 months of age. ~ Patients with subcutaneous tumors present either with an asymptomatic mass, or a draining coccygeal sinus. 5 Ependymomas at this site compose up to 20% of
CASE REPORTS The first case is that of a 16-year-old girl who noticed a coccygeal mass following minor trauma. It remained asymptomatic and of the same size over the next 2 years. The mass was midline, 2 x 3 cm, and had a rubbery firm consistency. It did not have an external opening. The physical examination and investigations, including chest x-ray and x-rays of the lumbosacral spine, were normal except for the presence of spina bifida occulta at the level of S i. Intraoperatively, a nonencapsulated lesion was found, adherent to the dermis and completely free of the coccyx. The cut surface of the tumor was grayish-tan, with a few areas of hemorrhage. Grossly, it resembled neural tissue. Histology revealed a myxopapillary ependymoma, and due to the proximity of tumor infiltration to the line of resection, a wider excision was undertaken four days later. No residual tumor was found in the second specimen. The second case is that of a 9-year-old boy who had undergone an elective excision of a "pilonidal cyst." The skin overlying the mass was normal and had no external openings. The operative findings consisted of a well-localized tumor, lobulated, and thinly encapsulated. The diagnosis was a well-differentiated ependymoma. The lines of resection were free of tumor. T h e microscopy of the first case is shown in Fig 1. T h e tumor has an ill-defined capsule, with infiltration into the surrounding fibrofatty tissues. There are solid areas, and less cellular ones, where the cuboidal ependymal cells are arranged on fibrovascular stalks in a papillary configuration. Perivascular degeneration results in a myxold appearance, giving rise to pseudorosette formation.
From the Departnlent of Surgery, Children's Hospital of Eastern Ontario, Ottawa. Presented at the 18th Annual Meeting of the Canadian Association of Paediatric Surgeons. ttalifax, Nova Scotia, August 28-30, 1986. Address reprint requests to Pierre Soucy, MD, Children's Hospital of Eastern Ontario, 401 Snlyth Rd, Ottawa, Ontario, K I H 8LI Canada. 9 1987 by Grune & Stratton, Inc. 0022-3468/87/2209-0002503.00/0 802
Fig 1. Case 1. Myxopapillary ependymoma. The ependymal cells are arranged in a papillary configuration. Note also the areas of myxoid degeneration (H&E, x 110). Journal of Pediatric Surgery, Vo122, No 9 (September),1987: pp 802-803
EXTRASPINAL EPENDYMOMA
803
sacrococcygeal lesions in infants under 1 year of age. 5 Presacral ependymomas present predominantly with symptoms secondary to compression of surrounding structures. It makes up 2% to 1 1% of retrorectal tumors. 6 The embryologic basis for the origin of these tumors seems to be from coccygeal medullary vestige. 7 By the end of the third month of gestation, only a remnant of the caudal portion of the neural tube remains at the tip of the coccyx. This ependyma-lined cavity appears to have have pinched off from the neural tube and assumes an extramedullary and at times, even an extraspinal position) It is seen not only in embryos at the site of closure of the posterior neuropore (postanal pit), but according to Bale, also in over 50% of infants up to the age of 1 y e a r ) The coccygeal medullary vestige, therefore, may be the source of heterotopic ependymal cell rests. The incidence of associated spina bifida occulta varies from 20% to 30%. 1"2"7"93~Presence of such developmental failure demonstrates incomplete closure of the neural arch, enhancing the possibility of ependymal heterotopia. Presacral ependymomas a/'e postulated to arise either from the cauda equina, extending through the sacral foramina into the soft
tissues anteriorly, 6'H or from extradural remnants of the ilium terminale. 7 Extraspinal ependymoma is a slow growing lowgrade malignancy. Although the tumor poses problems mainly in local control, it m a y metastasize to regional lymph nodes, lung, bone, and liver. 7'~2 Adequate treatment consists of wide excision. Repeated excisions for local recurrences achieve good results) '7'~~.Bilateral inguinal node dissection is performed in the face of nodal metastasis. 7'13 Whether this improves survival is difficult to determine given the small number of patients in each series and the slow growing nature of the tumor. Indeed, survival of 10 to 20 years after diagnosis of the tumor has been reported. 7'8'~~Radiotherapy is reserved for residual or inoperable tumors. 2'3"6 Excision o f pulmonary metastasis is performed Where feasible. 7't~ In the face of widespread disease, the average postoperative survival is about 10 years) Chemotherapy does little to arrest the progression of disease) '6'~~ In conclusion, sacrococcygeal tumors, especially in infants and young children, should alert the surgeon to the possibility of extraspinal ependymoma, and merit further investigations and complete excision.
REFERENCES
1. Cooper IS, Winchell MC, Kernohan JW: Tumours of the spinal cord. Surg GynecolObstet 92:183-190, 1951 2. Anderson MS: Myxopapillaryependymomaspresenting in the soft tissue over the sacrococcygealregion. Cancer 19:585-590, 1966 3. Morantz RA, KepesJ J, Batnitzky S, et al: Extraspinal ependymomas. J Neurosurg 51:383-391, 1979 4. Bales PM: Saerococcygealdevelopmental abnormalities and tumors in children. Perspect Pediatr Pathol 1:9-56, 1984 5. Ciraldo AV, Platt MS, Agamanolis DP, et al: Sacrococcygeal myxopapillary ependymomasand ependymal rests in infants and children. J Pediatr Surg 21:49-52, 1986 6. Heath MH: Presacralependymoma.Am J Clin Patho139:161166, 1963 7. WolffM, Santiago H, Duby MM: Delayed distant metastasis from a subcutaneoussacrococcygealependymoma.Cancer 30:10461067, 1972
8. Bale PM: Ependymal rests and subcutaneous sacrococcygeal ependymoma. Pathology 12:237-243, 1980 9. Sawai M, Vyas J J, Talvalkar GV: Subcutaneous sacrococcygeal myxopapillaryependymoma.Ind J Cancer 15:72-73, 1978 10. Vagaiwala MR, Robinson JS, Galicich JH, et al: Metastasizing extradural ependymoma of the sacrococcygealregion. Cancer 44:326-333, 1979 1I. Gerston, KF, Suprun H, Cohen H, et al: Presacral myxopapillary ependymoma presenting as an abdominal mass in a child. J Pediatr Surg 20:276-278, 1985 12. Dormal P, Baye R: Ependymomesacro-coccygien.Acta Chir Belg 84:27-30, 1984 13. Hendren TH, Hardin CA: Extradural metastatic ependymoma. Surgery 54:880-882, 1963