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Myxoid solitary fibrous tumour of the ischiorectal fossa
EJSO 2003; 29: 98±100 doi:10.1053/ejso.2002.1400
Myxoid solitary fibrous tumour of the ischiorectal fossa T. Yap, L. Hamzah, A. Oshowo and I. Taylor University College Hospitals NHS Trust, University of London, UK
Myxoid solitary fibrous tumours are a rare morphological sub-type of the rare solitary fibrous tumours. This case report appears to be the first reported ischiorectal occurrence of this rare tumour. # 2003 Published by Elsevier Science Ltd Key words: myxoid solitary fibrous tumour; liposarcoma.
INTRODUCTION An asymptomatic but growing perianal mass can present a diagnostic and hence therapeutic conundrum.
CASE STUDY A 41-year-old man presented with a 1-year history of a perianal lump which had increased in size and become hard and irregular. He was otherwise asymptomatic with normal bowel motions. An initial ultrasound assesment and biopsy of the mass was suspicious for a liposarcoma, and he was referred for excision of this mass. On examination in clinic, he had a firm 6 cm lump in the perianal region lateral to and pushing into the anal canal. It felt hard and irregular. An urgent magnetic resonance imaging scan (MRI) was performed to assess the extent of involvement of this lesion (Fig. 1). The pathology slides from the initial biopsy were reassessed. The histological analysis showed features of a myxoid spindle cell tumour rather than a liposarcoma, although the latter could not be excluded. His slides were sent to the Royal Marsden for a second opinion. This however was also inconclusive with the suspicion that the lesion was more typical of a spindle cell rather than liposarcomatous tumour. The MRI scan of the rectal and pre-sacral areas showed a relatively well defined 7 6 cm tumour below the levator plane in the left ischiorectal fossa, displacing the anal canal anteriorly and adjacent to the external sphincter and puborectalis. The tumour appeared well encapsulated with a high fluid content. There was no Correspondence to: Mr. T. Yap, Flat 3, 18 Bulstrode Street, London WIU 2JL, UK. E-mail: [email protected] 0748±7983/03/$30.00
evidence of local lymphadenopathy. The impression was of a soft tissue tumour, not obviously a liposarcoma, which would probably be surgically resectable from the anal canal given the nature of its capsule. A large 6 cm tumour densely adherent and possibly arising from or adjacent to the external sphincter muscles was widely excised, together with a segment of anal sphincter. The external anal sphincter muscles were repaired and there was good tone on rectal examination. The patient made a good post-operative recovery with no bowel problems and normal continence. The histology of the mass revealed a completely excised spindle cell tumour with extensive myxoid change and unusual collagen bundles, separated from surrounding tissues by a thin fibrous band. There was no evidence to suggest malignancy, with very mild pleomorphism in some of the tumour cells. Immunohistochemistry revealed the tumour cells were CD 34 positive but negative for markers like S 100 protein, desmin, neurofilament and epithelial membrane antigen (EMA). This histological and immunohistochemical profile suggested a myxoid solitary fibrous tumour, and further analysis at the Royal Marsden supported this diagnosis.
DISCUSSION Solitary fibrous tumours are rare mesenchymal tumours of adults. They usually arise in the pleura, but have been recognised in the lung1 and intra-abdominally in the retroperitoneum,2 pelvis,3 peritoneal cavity,4 pre-sacral space,5 and liver.6 Intra-abdominal solitary fibrous tumours usually present in adulthood7,8 either incidentally, with site-related symptoms or with systemic symptoms like arthralgia, hypoglycaemia and osteoarthropathy.9,10 #
2003 Published by Elsevier Science Ltd
MYXOID SOLITARY FIBROUS TUMOUR
99 34 positivity, with negative immunostains for S 100, EMA and smooth muscle actin. Although this series reported no recurrence or metastasis, post resection, there was limited follow up data (median follow up duration 19 months). A second earlier series of soft tissue solitary fibrous tumours in 15 patients, five of which were reported as histologically malignant, also reported no recurrence or metastasis post resection (median follow up duration 12 months).11 Another series of 24 extrapleural solitary fibrous tumours followed up for a mean of 41 months also emphasised the indolence of these tumours if completely excised, with no evidence of metastasis.4 This case appears to be the first ischiorectal myxoid solitary fibrous tumour reported. It also emphasizes the importance of the multi-disciplinary approach in diagnosis and management of these rare soft tissue tumours. MRI appears to be the preferred imaging modality for these soft tissue tumours, especially in our case given its location in the pre-sacral space where the anatomy and tissue constituents of the tumour on MRI help guide diagnosis and surgical resection.5,12,13 The recognition of this rare myxoid subset of solitary fibrous tumours is also important to differentiate between other myxoid spindle cell tumours with more aggressive potential such as myxoid liposarcoma (5-year soft tissue metastasis rate of 31%) which require more aggressive intervention.14 Additionally, this highlights the difficulties in histological diagnosis with small biopsy specimens, which have also been reported elsewhere.9 Complete surgical excision is necessary and is also advocated for extrapleural solitary fibrous tumours.15 MRI is important in both pre and post-operative management, if there is clinical suspicion. Fluorodeoxyglucose (FDG) PET scanning may also have a role in distinguishing high grade from low grade or benign soft tissue tumors and may prove useful in staging these malignant tumours.17
Figure 1 (a) Sagittal and (b) coronal T2 weighted magnetic resonance (MR) image of rectum showing clearly defined lesion displacing anal canal.
They are usually benign and managed by surgical resection.10 However, certain histological features are associated with rare locally aggressive or metastatic behaviour, including nuclear atypia and necrosis.3,7 Myxoid solitary fibrous tumours are a rare morphologic sub-group of the already rare solitary fibrous tumours and there is scant literature available on this subject. A series of seven cases of myxoid solitary fibrous tumours (median age at diagnosis 45 years) reported tumour location in the pleura. orbit, periparotid subcutaneous tissue, abdominal wall, chest wall and thigh.9 Atypical features of malignancy were not observed in all cases, and all seven tumours showed CD
REFERENCES 1. Younsen SA, Flynn S. Intrapulmonary localised fibrous tumor. Intraparenchymal so-called fibrous mesothelioma. Am J Clin Pathol 1998; 89: 365±9. 2. Ibrahim NB, Briggs JC, Corrin B. Double primary localised fibrous tumors of the pleura and retroperitoneum. Histopathology 1993; 22: 282±4. 3. Vallat-Decouvelaere A-V, Dry SM, Fletcher CDM. Atypical and malignant solitary solitary fibrous tumors in extrathoracic locations: evidence of comparability to intra-thoracic tumors. Am J Surg Pathol 1998; 22: 1501±11. 4. Brunnemann RB, Ro JY, Ordonez NG, et al. Extrapleural solitary fibrous tumor: a clinopathologic study of 24 cases. Mod Pathol 1999; 12: 1034±42. 5. Chun HJ, Byun JY, Jung SE, et al. Benign solitary fibrous tumor of the pre-sacral space: MRI findings. Br J Radiol 1998; 71: 677±9. 6. Bejarano PA, Blanco R, Hanto DW. Solitary fibrous tumor of the liver: a case report, review of literature and differential diagnosis of spindle cell lesions of the liver. Int J Surg Pathol 1998; 6: 93±100.
100 7. England M, Hockholzer L, McCarthy MJ. Localised and benign fibrous tumors of the pleura. Am J Surg Pathol 1998; 13: 640±58. 8. Nascimento AG. Solitary fibrous tumor: a ubiquitous neoplasm of mesenchymal differentiation. Adv Anat Pathol 1996; 3: 388±95. 9. Somerhausen NDSA, Rubin BP, Fletcher CDM. Myxoid solitary fibrous tumor: a sudy of seven cases with emphasis on differential diagnosis. Mod Pathol 1999; 12: 463±71. 10. Al-Nafussi A, Wong NA. Intra-abdominal spindle cell lesions: a review and practical aids to diagnosis. Histopathology 2001; 38: 387±402. 11. Nielsen GP, O'Connell UX, Dickersin GR et al. Solitary fibrous tumor of soft tissue: a report of 15 cases. Mod Pathol 1997; 10: 1028±37. 12. Lien H-H, Taksdal I. Magnetisk resonanstomografi innenfor onkologisk diagnostikk. Tidsskr Nor Laegeforen 2000; 120: 1054±9.
T. YAP ET AL. 13. Griffiths HJ, Galloway HR, Thompson RC et al. The use of MRI in the diagnosis of benign and malignant bone and soft tissue tumours. Aust Radiol 1993; 37: 35±9. 14. Spillane AJ, Fisher C, Thomas JM. Myxoid liposarcoma: the frequency and natural history of non-pulmonary soft tissue metastasis. Ann Surg Onc 1999; 6: 389±94. 15. Morimitsu Y, Nakajima M, Hisaoka M. Extrapleural solitary fibrous tumors: clinopathologic study of 17 cases. APMIS 2000; 108: 617±25. 16. Moskovic E, Serpell JW, Parsons C et al. Benign mimics of soft tissue sarcomas. Clin Radio 1992; 46: 248±52. 17. Lucas JD, O'Doherty MJ, Cronin BF et al. Prospective evaluation of soft tissue masses and sarcomas using fluorodeoxyglucose positron emission tomography. Br J Surg 1999; 86: 550±6. Accepted for publication 14 October 2002
Myxoid solitary fibrous tumour of the ischiorectal fossa T. Yap, L. Hamzah, A. Oshowo and I. Taylor University College Hospitals NHS Trust, University of London, UK
Myxoid solitary fibrous tumours are a rare morphological sub-type of the rare solitary fibrous tumours. This case report appears to be the first reported ischiorectal occurrence of this rare tumour. # 2003 Published by Elsevier Science Ltd Key words: myxoid solitary fibrous tumour; liposarcoma.
INTRODUCTION An asymptomatic but growing perianal mass can present a diagnostic and hence therapeutic conundrum.
CASE STUDY A 41-year-old man presented with a 1-year history of a perianal lump which had increased in size and become hard and irregular. He was otherwise asymptomatic with normal bowel motions. An initial ultrasound assesment and biopsy of the mass was suspicious for a liposarcoma, and he was referred for excision of this mass. On examination in clinic, he had a firm 6 cm lump in the perianal region lateral to and pushing into the anal canal. It felt hard and irregular. An urgent magnetic resonance imaging scan (MRI) was performed to assess the extent of involvement of this lesion (Fig. 1). The pathology slides from the initial biopsy were reassessed. The histological analysis showed features of a myxoid spindle cell tumour rather than a liposarcoma, although the latter could not be excluded. His slides were sent to the Royal Marsden for a second opinion. This however was also inconclusive with the suspicion that the lesion was more typical of a spindle cell rather than liposarcomatous tumour. The MRI scan of the rectal and pre-sacral areas showed a relatively well defined 7 6 cm tumour below the levator plane in the left ischiorectal fossa, displacing the anal canal anteriorly and adjacent to the external sphincter and puborectalis. The tumour appeared well encapsulated with a high fluid content. There was no Correspondence to: Mr. T. Yap, Flat 3, 18 Bulstrode Street, London WIU 2JL, UK. E-mail: [email protected] 0748±7983/03/$30.00
evidence of local lymphadenopathy. The impression was of a soft tissue tumour, not obviously a liposarcoma, which would probably be surgically resectable from the anal canal given the nature of its capsule. A large 6 cm tumour densely adherent and possibly arising from or adjacent to the external sphincter muscles was widely excised, together with a segment of anal sphincter. The external anal sphincter muscles were repaired and there was good tone on rectal examination. The patient made a good post-operative recovery with no bowel problems and normal continence. The histology of the mass revealed a completely excised spindle cell tumour with extensive myxoid change and unusual collagen bundles, separated from surrounding tissues by a thin fibrous band. There was no evidence to suggest malignancy, with very mild pleomorphism in some of the tumour cells. Immunohistochemistry revealed the tumour cells were CD 34 positive but negative for markers like S 100 protein, desmin, neurofilament and epithelial membrane antigen (EMA). This histological and immunohistochemical profile suggested a myxoid solitary fibrous tumour, and further analysis at the Royal Marsden supported this diagnosis.
DISCUSSION Solitary fibrous tumours are rare mesenchymal tumours of adults. They usually arise in the pleura, but have been recognised in the lung1 and intra-abdominally in the retroperitoneum,2 pelvis,3 peritoneal cavity,4 pre-sacral space,5 and liver.6 Intra-abdominal solitary fibrous tumours usually present in adulthood7,8 either incidentally, with site-related symptoms or with systemic symptoms like arthralgia, hypoglycaemia and osteoarthropathy.9,10 #
2003 Published by Elsevier Science Ltd
MYXOID SOLITARY FIBROUS TUMOUR
99 34 positivity, with negative immunostains for S 100, EMA and smooth muscle actin. Although this series reported no recurrence or metastasis, post resection, there was limited follow up data (median follow up duration 19 months). A second earlier series of soft tissue solitary fibrous tumours in 15 patients, five of which were reported as histologically malignant, also reported no recurrence or metastasis post resection (median follow up duration 12 months).11 Another series of 24 extrapleural solitary fibrous tumours followed up for a mean of 41 months also emphasised the indolence of these tumours if completely excised, with no evidence of metastasis.4 This case appears to be the first ischiorectal myxoid solitary fibrous tumour reported. It also emphasizes the importance of the multi-disciplinary approach in diagnosis and management of these rare soft tissue tumours. MRI appears to be the preferred imaging modality for these soft tissue tumours, especially in our case given its location in the pre-sacral space where the anatomy and tissue constituents of the tumour on MRI help guide diagnosis and surgical resection.5,12,13 The recognition of this rare myxoid subset of solitary fibrous tumours is also important to differentiate between other myxoid spindle cell tumours with more aggressive potential such as myxoid liposarcoma (5-year soft tissue metastasis rate of 31%) which require more aggressive intervention.14 Additionally, this highlights the difficulties in histological diagnosis with small biopsy specimens, which have also been reported elsewhere.9 Complete surgical excision is necessary and is also advocated for extrapleural solitary fibrous tumours.15 MRI is important in both pre and post-operative management, if there is clinical suspicion. Fluorodeoxyglucose (FDG) PET scanning may also have a role in distinguishing high grade from low grade or benign soft tissue tumors and may prove useful in staging these malignant tumours.17
Figure 1 (a) Sagittal and (b) coronal T2 weighted magnetic resonance (MR) image of rectum showing clearly defined lesion displacing anal canal.
They are usually benign and managed by surgical resection.10 However, certain histological features are associated with rare locally aggressive or metastatic behaviour, including nuclear atypia and necrosis.3,7 Myxoid solitary fibrous tumours are a rare morphologic sub-group of the already rare solitary fibrous tumours and there is scant literature available on this subject. A series of seven cases of myxoid solitary fibrous tumours (median age at diagnosis 45 years) reported tumour location in the pleura. orbit, periparotid subcutaneous tissue, abdominal wall, chest wall and thigh.9 Atypical features of malignancy were not observed in all cases, and all seven tumours showed CD
REFERENCES 1. Younsen SA, Flynn S. Intrapulmonary localised fibrous tumor. Intraparenchymal so-called fibrous mesothelioma. Am J Clin Pathol 1998; 89: 365±9. 2. Ibrahim NB, Briggs JC, Corrin B. Double primary localised fibrous tumors of the pleura and retroperitoneum. Histopathology 1993; 22: 282±4. 3. Vallat-Decouvelaere A-V, Dry SM, Fletcher CDM. Atypical and malignant solitary solitary fibrous tumors in extrathoracic locations: evidence of comparability to intra-thoracic tumors. Am J Surg Pathol 1998; 22: 1501±11. 4. Brunnemann RB, Ro JY, Ordonez NG, et al. Extrapleural solitary fibrous tumor: a clinopathologic study of 24 cases. Mod Pathol 1999; 12: 1034±42. 5. Chun HJ, Byun JY, Jung SE, et al. Benign solitary fibrous tumor of the pre-sacral space: MRI findings. Br J Radiol 1998; 71: 677±9. 6. Bejarano PA, Blanco R, Hanto DW. Solitary fibrous tumor of the liver: a case report, review of literature and differential diagnosis of spindle cell lesions of the liver. Int J Surg Pathol 1998; 6: 93±100.
100 7. England M, Hockholzer L, McCarthy MJ. Localised and benign fibrous tumors of the pleura. Am J Surg Pathol 1998; 13: 640±58. 8. Nascimento AG. Solitary fibrous tumor: a ubiquitous neoplasm of mesenchymal differentiation. Adv Anat Pathol 1996; 3: 388±95. 9. Somerhausen NDSA, Rubin BP, Fletcher CDM. Myxoid solitary fibrous tumor: a sudy of seven cases with emphasis on differential diagnosis. Mod Pathol 1999; 12: 463±71. 10. Al-Nafussi A, Wong NA. Intra-abdominal spindle cell lesions: a review and practical aids to diagnosis. Histopathology 2001; 38: 387±402. 11. Nielsen GP, O'Connell UX, Dickersin GR et al. Solitary fibrous tumor of soft tissue: a report of 15 cases. Mod Pathol 1997; 10: 1028±37. 12. Lien H-H, Taksdal I. Magnetisk resonanstomografi innenfor onkologisk diagnostikk. Tidsskr Nor Laegeforen 2000; 120: 1054±9.
T. YAP ET AL. 13. Griffiths HJ, Galloway HR, Thompson RC et al. The use of MRI in the diagnosis of benign and malignant bone and soft tissue tumours. Aust Radiol 1993; 37: 35±9. 14. Spillane AJ, Fisher C, Thomas JM. Myxoid liposarcoma: the frequency and natural history of non-pulmonary soft tissue metastasis. Ann Surg Onc 1999; 6: 389±94. 15. Morimitsu Y, Nakajima M, Hisaoka M. Extrapleural solitary fibrous tumors: clinopathologic study of 17 cases. APMIS 2000; 108: 617±25. 16. Moskovic E, Serpell JW, Parsons C et al. Benign mimics of soft tissue sarcomas. Clin Radio 1992; 46: 248±52. 17. Lucas JD, O'Doherty MJ, Cronin BF et al. Prospective evaluation of soft tissue masses and sarcomas using fluorodeoxyglucose positron emission tomography. Br J Surg 1999; 86: 550±6. Accepted for publication 14 October 2002