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A rare cause of low back pain: A report of presacral schwannoma
Clinical Queries: Nephrology 5 (2016) 42–45
Contents lists available at ScienceDirect
Clinical Queries: Nephrology journal homepage: www.elsevier.com/locate/cqn
Case report
A rare cause of low back pain: A report of presacral schwannoma Shruti P. Gandhi a,*, Syed Jamal Rizvi b, Kamlesh S. Suthar c, Kajal N. Patel a a
Department of Radiology & Imaging, G. R. Doshi and K. M. Mehta Institute of Kidney Diseases and Research Centre (IKDRC), Dr. H.L. Trivedi Institute of Transplantation Sciences (ITS), Civil Hospital Campus, Asarwa, Ahmedabad 380016, Gujarat, India b Department of Urology and Transplantation Surgery, G. R. Doshi and K. M. Mehta Institute of Kidney Diseases and Research Centre (IKDRC), Dr. H.L. Trivedi Institute of Transplantation Sciences (ITS), Civil Hospital Campus, Asarwa, Ahmedabad 380016, Gujarat, India c Department of Pathology, Lab Medicine, Transfusion Services and Immunohematology, G. R. Doshi and K. M. Mehta Institute of Kidney Diseases and Research Centre (IKDRC), Dr. H.L. Trivedi Institute of Transplantation Sciences (ITS), Civil Hospital Campus, Asarwa, Ahmedabad 380016, Gujarat, India
A R T I C L E I N F O
A B S T R A C T
Article history: Received 4 July 2016 Accepted 25 July 2016 Available online 15 November 2016
The presacral space is the site of a group of heterogeneous and rare tumors that are often indolent and produce nonspecific symptoms. Here we report a case of large multiloculated cystic mass in 53-year-old male presented with right-sided low backache. Provisional diagnosis of presacral schwannoma was made with the help computed tomography (CT) study and diagnosis was confirmed by histopathology. ß 2016 Published by Elsevier, a division of RELX India, Pvt. Ltd.
Keywords: Presacral schwannoma Backache
1. Introduction The presacral space is the site of a group of heterogeneous and rare tumors that are often indolent and produce nonspecific symptoms. Reports from various large referral centers would indicate that their incidence may be as low as 1 in 40,000 hospital admissions (0.014%).1 Although neurogenic tumors consists of 10– 15% of presacral region tumors, schwannoma in this location is rare and generally asymptomatic. Here we report a case of large multiloculated cystic mass in 53-year-old male presented with right-sided low backache. Provisional diagnosis of presacral schwannoma was made with the help computed tomography (CT) study and diagnosis was confirmed by histopathology. 2. Case report A 53-year-old male presented to our Institute’s out patient department with history of right-sided low backache since 2 months. There was no history of tingling, numbness, paraesthesia or radicular pain in lower limb. There were no bladder or bowel
* Corresponding author at: 13-Vrundavan Apartment, Plot No. 7 Laxminarayan Society, Near Shantinagar Jain Temple, Usmanpura, Ahmedabad 380013, Gujarat, India. E-mail addresses: [email protected] (S.P. Gandhi), [email protected] (S.J. Rizvi), [email protected] (K.S. Suthar), [email protected] (K.N. Patel). http://dx.doi.org/10.1016/j.cqn.2016.07.003 2211-9477/ß 2016 Published by Elsevier, a division of RELX India, Pvt. Ltd.
complaints. Plain X-ray lumbo sacral spine was normal. A physical examination revealed a large mass in pelvis. Ultrasonography of abdomen showed a well-defined, multiloculated cystic mass in right side of the pelvis. Blood test results, including the levels of the tumor markers – prostate specific antigen, carcinoembryonic antigen, a-fetoprotein, carbohydrate antigens 199 and 125 were within normal limits. There was no family history or features of neurofibromatosis. Contrast enhanced CT scan of abdomen showed a 9.9 cm 6.6 cm 5.6 cm sized cystic mass with enhancing wall and septa in right presacral region displacing normal smooth ureter and urinary bladder medially (Fig. 1). The mass was positioned anterolateral to the rectum, medial to the right sacroiliac joint and lower limit of mass was above the level of S3. There was no evidence of fat density, calcification or hemorrhage within mass. Scalloping of sacral ala was seen (Fig. 2). There was no evidence of hydronephrosis or hydroureter on right side. No evidence of enlarged lymph nodes or distant metastasis was found in abdomen. Looking to the anatomical situation and cystic nature of mass provisional diagnosis of neurogenic tumor – schwannoma was made. Patient was taken up for surgery via anterior approach. Intraoperatively a large mass arising from sacral nerve root was found. Complete excision was not possible; about 3/ 4 of mass was resected and patient recovered well. Histopathology showed tumor composed of intersecting fascicles of spindle cells, Antoni A areas with verocay bodies (Figs. 3 and 4). No evidence of malignancy was noted. Follow up CT scan at 9 months showed minimal residual mass lesion in presacral
S.P. Gandhi et al. / Clinical Queries: Nephrology 5 (2016) 42–45
43
Fig. 1. Contrast enhanced CT scan of abdomen and pelvis showing large multiloculated mass lesion right presacral region in causing displacement of right lower ureter and urinary bladder. The mass is located above the level of S3.
Fig. 2. Contrast enhanced CT scan of pelvis showing a multiloculated cystic mass in presacral region on right side with scalloping of anterior wall of sacrum.
Fig. 3. Image shows microscopic appearance of schwannoma (H&E stain, 200): nuclear palisading (Antoni A area).
Fig. 4. Image shows microscopic appearance of schwannoma (H&E stain, 100): verocay body.
Fig. 5. Contrast enhanced CT scan of pelvis 9 months after surgery showing minimal residual mass lesion in presacral area.
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S.P. Gandhi et al. / Clinical Queries: Nephrology 5 (2016) 42–45
area without regrowth or metastasis (Fig. 5). Regular follow up was advised. 3. Discussion Schwannoma are benign neoplasm arising from the nerve sheath that usually affects the head, neck and flexor surfaces of the extremities. They are almost invariably slow growing, nonaggressive neoplasm that are solitary in the vast majority of cases. In 5–18% of cases they are associated with neurofibromatosis Type I,2 in which case lesions may be multiple and often plexiform. Pelvis is a rare site for schwannoma and accounts for less than 1% of reported cases.3 It usually affects the patients aged 20–50 years and males are most frequently affected than females.4 Although tumors arise from peripheral nerve sheath, it rarely elicit any clinically detectable neurological deficit.5 Based on their location with respect to the sacrum, these tumors are classified into three types.6 Type 1 – localized to sacrum. They arise from a peripheral nerve within the sacrum and produce moderate to massive bone destruction before extending into soft tissues. Type 2 (most common) is the one which protrudes to adjacent cavities by invading anterior or posterior sacral wall. Type 3 tumor localized in the presacral region. Presacral schwannoma presumably arise from a peripheral nerve in or adjacent to anterior sacral foramen, therefore they are able to grow outside the confines of the bone with limited degree of secondary bone involvement7 as in our case. Patient may be asymptomatic, may present with nonspecific symptoms, vague abdominal pain or back pain. Lesions eroding through sacrum can present with lumbo sacral or radicular pain. Depending on the localization of tumor urinary and bowel disturbances can be seen. In our case tumor able to grow to large size with only minor complaints because of absences of compression of neurovascular structures and absence of bowel, bladder or bone involvement. Goal of imaging is not only to provide exact diagnosis but also to relay imperative preoperative information to surgeons. Plain Xrays of the sacrum can identify osseous expansion, destruction, and/or calcification of soft tissue masses, but not helpful in rendering a specific diagnosis. Ultrasonography can be helpful in differentiating solid lesions from cystic one. CT and magnetic resonance imaging (MRI) complement each other and are the most important radiographic studies in evaluating a patient with a presacral lesion. CT is the best study to evaluate cortical bone destruction. At CT, schwannoma typically are seen as a heterogeneous presacral soft-tissue mass, with or without calcifications. CT cannot differentiate presacral tumors from presacral schwannoma. However cystic changes may be one of the characteristic radiological features.7 On MR imaging they appear heterogeneous with low signal intensity on T1-weighted images and high signal intensity on T2weighted images, and tend to have small cystic areas and a thin pseudo capsule. MRI is also more sensitive than CT in spinal imaging and in evaluating the extent of marrow involvement in bone. MR imaging features which suggest the diagnosis of neurogenic tumor include the presence of fusiform shaped mass with an entering or exiting tail representing host nerve.8 Target and fascicular signs are characteristic radiological features of schwannoma, not frequently seen in pelvic schwannoma by virtue of the enormous size of the lesion as compared with underlying nerve. Angiogram and venogram can be helpful to delineate vascular involvement and anatomy. Tissue diagnosis can be achieved by FNAC and excision biopsies. Image guided biopsies and FNAC are not always reliable as they should contain significant amount of Schwann cells, and FNAC from the areas of degeneration will be misdiagnosed as malignant. In our case provisional diagnosis of schwannoma was made on the basis of cystic nature
of tumor and scalloping of sacral bone; which obviates need for tissue biopsy. Malignant transformation of schwannoma is rare and usually observed in cases with underlying von-Recklinghausen’s disease.6 Radiologically, a malignant schwannoma has irregular margins and infiltrates the adjacent structures. Distant metastases via perineural and intra-neural routes are characteristic features. The differential diagnosis of a presacral mass can be categorized as congenital (65%), neurogenic (12%), osseous (11%) or miscellaneous (12%). Radiologically these masses can also be categorized as either vascular or hyper vascular (solitary fibrous tumor, paraganglioma, pelvic arteriovenous malformation, Klippel–Tre´naunay–Weber syndrome, extra intestinal gastrointestinal stromal tumor), fat-containing (dermoid, lipoma, liposarcoma, myelolipoma, presacral teratoma), calcified (calcified lymphocele, calcified rejected transplant kidney, rare sarcomas), myxoid (schwannoma, plexiform neurofibroma, myxoma) or cystic.9 In our case imaging studies revealed a cystic tumor. When cystic presacral tumors are concerned the differential diagnosis includes serous and mucinous cystadenoma or cystadenocarcinoma of ovaries, presacral epidermal cyst, pelvic lymphangioma, tailgut cyst, abscess, necrotic soft-tissue sarcoma, necrotic metastatic lymph adenopathy, epidermoid cyst, dermoid cyst, teratoma, endometrial cyst, anterior sacral meningocele, mulllerian duct cyst, and retroperitoneal nerve sheath tumor. Tailgut cysts and lymphangioma have tendency to be multilocular. Remainder of the differential is primarily unilocular. Dermoid cyst and teratoma contains fat. Anterior sacral meningocele shows presence of sacral erosion. Retroperitoneal lymph nodes distinguished by evidence of lymphadenopathy at other sites and the ovarian tumor distinguished by identifying the normal separate ovaries. Infectious, inflammatory, and posttraumatic conditions may be diagnosed on the basis of characteristic imaging features in the appropriate clinical setting: presacral abscesses demonstrate an enhancing rim, and hematomas demonstrate an area of high attenuation at CT. Diagnosis of presacral schwannoma can be suggested when presacral soft tissue mass arising just to one side of the mid line with minor bone erosion.10 Previous studies have reported the misdiagnosis of schwannoma as psoas abscess, ovarian dermoid cyst, ovarian teratoma or pendunculated leiomyoma.11–13 In terms of treatment, surgery is the modality of choice for pelvic schwannoma. In malignant schwannoma, adjuvant chemotherapy or radiotherapy has marginal added benefit. Craniocaudal extent of the mass relative to S3 is the primary determining factor for choice of surgical approach. Tumors above the level of S3 approached by transabdominal route and below the level of S3 approached by transrectal, trans sacral or trans-sphinteric route. Combined approach required for tumors that span the level of S3 or if there is sacral invasion. Anterior approach has advantage of excellent evaluation of pelvic structures and ureters. As our patient had mass above the level of S3 anterior extraperitoneal approach was successfully used to remove the presacral schwannoma. Postoperative period was uneventful.
4. Conclusion Presacral schwannoma is a rare disorder and most cases are benign. Radiology plays an important role in the diagnosis of presacral schwannoma. It is important to identify a malignant schwannoma, because it is managed differently and has a poor prognosis. It also is important to be familiar with the imaging characteristics of the various pelvic cysts, their anatomic locations, and the patient’s clinical history to make an accurate diagnosis.
S.P. Gandhi et al. / Clinical Queries: Nephrology 5 (2016) 42–45
Conflicts of interest The authors have none to declare. Acknowledgment We are also thankful to our librarian Jyotsana Suthar for literature search and submission. References 1. Whittaker LD, Pemberton JD. Tumors ventral to the sacrum. Ann Surg. 1938;107(1): 96–106. 2. Antinheimo J, Sankila R, Carpe´n O, Pukkala E, Sainio M, Ja¨a¨skela¨inen J. Populationbased analysis of sporadic and type 2 neurofibromatosis-associated meningiomas and schwannomas. Neurology. 2000;54(1):71–76. 3. Zou F, Dai M, Zhang B, Nie T. Misdiagnosis of a giant intrapelvic schwannoma: a case report. Oncol Lett. 2013;6(6):1646–1648. 4. Wong CS, Chu TY, Tam KF. Retroperitoneal schwanoma: a common tumor in an uncommon site. Hong Kong Med J. 2010;16(1):66–68.
45
5. Herregodts P, Vloeberghs M, Schmedding E, Goossens A, Stadnik T, D’Haens J. Solitary dorsal intramedullary schwannoma. Case report. J Neurosurg. 1991; 74(5):816–820. 6. Klimo Jr P, Rao G, Schmidt RH, Schmidt MH. Nerve sheath tumors involving the sacrum. Case report and classification scheme. Neurosurg Focus. 2003;15(2): E12. 7. Lin H-Y, Huang Y-H, Tang T-N, Chiu AW. Presacral schwannoma. A case report. JTUA. 2004;15:24–27. 8. Suh JS, Abenoza P, Galloway HR, Everson LI, Griffiths HJ. Peripheral (extra cranial) nerve tumors. Correlation of MR imaging and histological findings. Radiology. 1992;183(2):341–346. 9. Shanbhogue AK, Fasih N, Macdonald DB, Sheikh AM, Menias CO, Prasad SR. Uncommon primary pelvic retroperitoneal masses in adults: a pattern based imaging approach. Radiographics. 2012;32(3):795–817. 10. Nyapathy V, Murthy UK, Chintamani J, Sridhar DY. A case report of a giant presacral cystic schwannoma with sigmoid megacolon. J Radiol Case Rep. 2009;3(12):31–37. 11. Kishi Y, Kajiwara S, Seta S, Kawauchi N, Suzuki T, Sasaki K. Retroperitoneal schwannoma misdiagnosed as a psoas abscess: report of a case. Surg Today. 2002; 32(9):849–852. 12. Ibraheim M, Ikomi A, Khan F. A pelvic retroperitoneal schwannoma mimicking an ovarian dermoid cyst in pregnancy. J Obstet Gynaecol. 2005;25(6):620–621. 13. Santala M, Mosorin M-E, Liakka A. Benign presacral schwannoma mimicking pedunculated leiomyoma. J Turk Ger Gynecol Assoc. 2007;8:90–93.
Contents lists available at ScienceDirect
Clinical Queries: Nephrology journal homepage: www.elsevier.com/locate/cqn
Case report
A rare cause of low back pain: A report of presacral schwannoma Shruti P. Gandhi a,*, Syed Jamal Rizvi b, Kamlesh S. Suthar c, Kajal N. Patel a a
Department of Radiology & Imaging, G. R. Doshi and K. M. Mehta Institute of Kidney Diseases and Research Centre (IKDRC), Dr. H.L. Trivedi Institute of Transplantation Sciences (ITS), Civil Hospital Campus, Asarwa, Ahmedabad 380016, Gujarat, India b Department of Urology and Transplantation Surgery, G. R. Doshi and K. M. Mehta Institute of Kidney Diseases and Research Centre (IKDRC), Dr. H.L. Trivedi Institute of Transplantation Sciences (ITS), Civil Hospital Campus, Asarwa, Ahmedabad 380016, Gujarat, India c Department of Pathology, Lab Medicine, Transfusion Services and Immunohematology, G. R. Doshi and K. M. Mehta Institute of Kidney Diseases and Research Centre (IKDRC), Dr. H.L. Trivedi Institute of Transplantation Sciences (ITS), Civil Hospital Campus, Asarwa, Ahmedabad 380016, Gujarat, India
A R T I C L E I N F O
A B S T R A C T
Article history: Received 4 July 2016 Accepted 25 July 2016 Available online 15 November 2016
The presacral space is the site of a group of heterogeneous and rare tumors that are often indolent and produce nonspecific symptoms. Here we report a case of large multiloculated cystic mass in 53-year-old male presented with right-sided low backache. Provisional diagnosis of presacral schwannoma was made with the help computed tomography (CT) study and diagnosis was confirmed by histopathology. ß 2016 Published by Elsevier, a division of RELX India, Pvt. Ltd.
Keywords: Presacral schwannoma Backache
1. Introduction The presacral space is the site of a group of heterogeneous and rare tumors that are often indolent and produce nonspecific symptoms. Reports from various large referral centers would indicate that their incidence may be as low as 1 in 40,000 hospital admissions (0.014%).1 Although neurogenic tumors consists of 10– 15% of presacral region tumors, schwannoma in this location is rare and generally asymptomatic. Here we report a case of large multiloculated cystic mass in 53-year-old male presented with right-sided low backache. Provisional diagnosis of presacral schwannoma was made with the help computed tomography (CT) study and diagnosis was confirmed by histopathology. 2. Case report A 53-year-old male presented to our Institute’s out patient department with history of right-sided low backache since 2 months. There was no history of tingling, numbness, paraesthesia or radicular pain in lower limb. There were no bladder or bowel
* Corresponding author at: 13-Vrundavan Apartment, Plot No. 7 Laxminarayan Society, Near Shantinagar Jain Temple, Usmanpura, Ahmedabad 380013, Gujarat, India. E-mail addresses: [email protected] (S.P. Gandhi), [email protected] (S.J. Rizvi), [email protected] (K.S. Suthar), [email protected] (K.N. Patel). http://dx.doi.org/10.1016/j.cqn.2016.07.003 2211-9477/ß 2016 Published by Elsevier, a division of RELX India, Pvt. Ltd.
complaints. Plain X-ray lumbo sacral spine was normal. A physical examination revealed a large mass in pelvis. Ultrasonography of abdomen showed a well-defined, multiloculated cystic mass in right side of the pelvis. Blood test results, including the levels of the tumor markers – prostate specific antigen, carcinoembryonic antigen, a-fetoprotein, carbohydrate antigens 199 and 125 were within normal limits. There was no family history or features of neurofibromatosis. Contrast enhanced CT scan of abdomen showed a 9.9 cm 6.6 cm 5.6 cm sized cystic mass with enhancing wall and septa in right presacral region displacing normal smooth ureter and urinary bladder medially (Fig. 1). The mass was positioned anterolateral to the rectum, medial to the right sacroiliac joint and lower limit of mass was above the level of S3. There was no evidence of fat density, calcification or hemorrhage within mass. Scalloping of sacral ala was seen (Fig. 2). There was no evidence of hydronephrosis or hydroureter on right side. No evidence of enlarged lymph nodes or distant metastasis was found in abdomen. Looking to the anatomical situation and cystic nature of mass provisional diagnosis of neurogenic tumor – schwannoma was made. Patient was taken up for surgery via anterior approach. Intraoperatively a large mass arising from sacral nerve root was found. Complete excision was not possible; about 3/ 4 of mass was resected and patient recovered well. Histopathology showed tumor composed of intersecting fascicles of spindle cells, Antoni A areas with verocay bodies (Figs. 3 and 4). No evidence of malignancy was noted. Follow up CT scan at 9 months showed minimal residual mass lesion in presacral
S.P. Gandhi et al. / Clinical Queries: Nephrology 5 (2016) 42–45
43
Fig. 1. Contrast enhanced CT scan of abdomen and pelvis showing large multiloculated mass lesion right presacral region in causing displacement of right lower ureter and urinary bladder. The mass is located above the level of S3.
Fig. 2. Contrast enhanced CT scan of pelvis showing a multiloculated cystic mass in presacral region on right side with scalloping of anterior wall of sacrum.
Fig. 3. Image shows microscopic appearance of schwannoma (H&E stain, 200): nuclear palisading (Antoni A area).
Fig. 4. Image shows microscopic appearance of schwannoma (H&E stain, 100): verocay body.
Fig. 5. Contrast enhanced CT scan of pelvis 9 months after surgery showing minimal residual mass lesion in presacral area.
44
S.P. Gandhi et al. / Clinical Queries: Nephrology 5 (2016) 42–45
area without regrowth or metastasis (Fig. 5). Regular follow up was advised. 3. Discussion Schwannoma are benign neoplasm arising from the nerve sheath that usually affects the head, neck and flexor surfaces of the extremities. They are almost invariably slow growing, nonaggressive neoplasm that are solitary in the vast majority of cases. In 5–18% of cases they are associated with neurofibromatosis Type I,2 in which case lesions may be multiple and often plexiform. Pelvis is a rare site for schwannoma and accounts for less than 1% of reported cases.3 It usually affects the patients aged 20–50 years and males are most frequently affected than females.4 Although tumors arise from peripheral nerve sheath, it rarely elicit any clinically detectable neurological deficit.5 Based on their location with respect to the sacrum, these tumors are classified into three types.6 Type 1 – localized to sacrum. They arise from a peripheral nerve within the sacrum and produce moderate to massive bone destruction before extending into soft tissues. Type 2 (most common) is the one which protrudes to adjacent cavities by invading anterior or posterior sacral wall. Type 3 tumor localized in the presacral region. Presacral schwannoma presumably arise from a peripheral nerve in or adjacent to anterior sacral foramen, therefore they are able to grow outside the confines of the bone with limited degree of secondary bone involvement7 as in our case. Patient may be asymptomatic, may present with nonspecific symptoms, vague abdominal pain or back pain. Lesions eroding through sacrum can present with lumbo sacral or radicular pain. Depending on the localization of tumor urinary and bowel disturbances can be seen. In our case tumor able to grow to large size with only minor complaints because of absences of compression of neurovascular structures and absence of bowel, bladder or bone involvement. Goal of imaging is not only to provide exact diagnosis but also to relay imperative preoperative information to surgeons. Plain Xrays of the sacrum can identify osseous expansion, destruction, and/or calcification of soft tissue masses, but not helpful in rendering a specific diagnosis. Ultrasonography can be helpful in differentiating solid lesions from cystic one. CT and magnetic resonance imaging (MRI) complement each other and are the most important radiographic studies in evaluating a patient with a presacral lesion. CT is the best study to evaluate cortical bone destruction. At CT, schwannoma typically are seen as a heterogeneous presacral soft-tissue mass, with or without calcifications. CT cannot differentiate presacral tumors from presacral schwannoma. However cystic changes may be one of the characteristic radiological features.7 On MR imaging they appear heterogeneous with low signal intensity on T1-weighted images and high signal intensity on T2weighted images, and tend to have small cystic areas and a thin pseudo capsule. MRI is also more sensitive than CT in spinal imaging and in evaluating the extent of marrow involvement in bone. MR imaging features which suggest the diagnosis of neurogenic tumor include the presence of fusiform shaped mass with an entering or exiting tail representing host nerve.8 Target and fascicular signs are characteristic radiological features of schwannoma, not frequently seen in pelvic schwannoma by virtue of the enormous size of the lesion as compared with underlying nerve. Angiogram and venogram can be helpful to delineate vascular involvement and anatomy. Tissue diagnosis can be achieved by FNAC and excision biopsies. Image guided biopsies and FNAC are not always reliable as they should contain significant amount of Schwann cells, and FNAC from the areas of degeneration will be misdiagnosed as malignant. In our case provisional diagnosis of schwannoma was made on the basis of cystic nature
of tumor and scalloping of sacral bone; which obviates need for tissue biopsy. Malignant transformation of schwannoma is rare and usually observed in cases with underlying von-Recklinghausen’s disease.6 Radiologically, a malignant schwannoma has irregular margins and infiltrates the adjacent structures. Distant metastases via perineural and intra-neural routes are characteristic features. The differential diagnosis of a presacral mass can be categorized as congenital (65%), neurogenic (12%), osseous (11%) or miscellaneous (12%). Radiologically these masses can also be categorized as either vascular or hyper vascular (solitary fibrous tumor, paraganglioma, pelvic arteriovenous malformation, Klippel–Tre´naunay–Weber syndrome, extra intestinal gastrointestinal stromal tumor), fat-containing (dermoid, lipoma, liposarcoma, myelolipoma, presacral teratoma), calcified (calcified lymphocele, calcified rejected transplant kidney, rare sarcomas), myxoid (schwannoma, plexiform neurofibroma, myxoma) or cystic.9 In our case imaging studies revealed a cystic tumor. When cystic presacral tumors are concerned the differential diagnosis includes serous and mucinous cystadenoma or cystadenocarcinoma of ovaries, presacral epidermal cyst, pelvic lymphangioma, tailgut cyst, abscess, necrotic soft-tissue sarcoma, necrotic metastatic lymph adenopathy, epidermoid cyst, dermoid cyst, teratoma, endometrial cyst, anterior sacral meningocele, mulllerian duct cyst, and retroperitoneal nerve sheath tumor. Tailgut cysts and lymphangioma have tendency to be multilocular. Remainder of the differential is primarily unilocular. Dermoid cyst and teratoma contains fat. Anterior sacral meningocele shows presence of sacral erosion. Retroperitoneal lymph nodes distinguished by evidence of lymphadenopathy at other sites and the ovarian tumor distinguished by identifying the normal separate ovaries. Infectious, inflammatory, and posttraumatic conditions may be diagnosed on the basis of characteristic imaging features in the appropriate clinical setting: presacral abscesses demonstrate an enhancing rim, and hematomas demonstrate an area of high attenuation at CT. Diagnosis of presacral schwannoma can be suggested when presacral soft tissue mass arising just to one side of the mid line with minor bone erosion.10 Previous studies have reported the misdiagnosis of schwannoma as psoas abscess, ovarian dermoid cyst, ovarian teratoma or pendunculated leiomyoma.11–13 In terms of treatment, surgery is the modality of choice for pelvic schwannoma. In malignant schwannoma, adjuvant chemotherapy or radiotherapy has marginal added benefit. Craniocaudal extent of the mass relative to S3 is the primary determining factor for choice of surgical approach. Tumors above the level of S3 approached by transabdominal route and below the level of S3 approached by transrectal, trans sacral or trans-sphinteric route. Combined approach required for tumors that span the level of S3 or if there is sacral invasion. Anterior approach has advantage of excellent evaluation of pelvic structures and ureters. As our patient had mass above the level of S3 anterior extraperitoneal approach was successfully used to remove the presacral schwannoma. Postoperative period was uneventful.
4. Conclusion Presacral schwannoma is a rare disorder and most cases are benign. Radiology plays an important role in the diagnosis of presacral schwannoma. It is important to identify a malignant schwannoma, because it is managed differently and has a poor prognosis. It also is important to be familiar with the imaging characteristics of the various pelvic cysts, their anatomic locations, and the patient’s clinical history to make an accurate diagnosis.
S.P. Gandhi et al. / Clinical Queries: Nephrology 5 (2016) 42–45
Conflicts of interest The authors have none to declare. Acknowledgment We are also thankful to our librarian Jyotsana Suthar for literature search and submission. References 1. Whittaker LD, Pemberton JD. Tumors ventral to the sacrum. Ann Surg. 1938;107(1): 96–106. 2. Antinheimo J, Sankila R, Carpe´n O, Pukkala E, Sainio M, Ja¨a¨skela¨inen J. Populationbased analysis of sporadic and type 2 neurofibromatosis-associated meningiomas and schwannomas. Neurology. 2000;54(1):71–76. 3. Zou F, Dai M, Zhang B, Nie T. Misdiagnosis of a giant intrapelvic schwannoma: a case report. Oncol Lett. 2013;6(6):1646–1648. 4. Wong CS, Chu TY, Tam KF. Retroperitoneal schwanoma: a common tumor in an uncommon site. Hong Kong Med J. 2010;16(1):66–68.
45
5. Herregodts P, Vloeberghs M, Schmedding E, Goossens A, Stadnik T, D’Haens J. Solitary dorsal intramedullary schwannoma. Case report. J Neurosurg. 1991; 74(5):816–820. 6. Klimo Jr P, Rao G, Schmidt RH, Schmidt MH. Nerve sheath tumors involving the sacrum. Case report and classification scheme. Neurosurg Focus. 2003;15(2): E12. 7. Lin H-Y, Huang Y-H, Tang T-N, Chiu AW. Presacral schwannoma. A case report. JTUA. 2004;15:24–27. 8. Suh JS, Abenoza P, Galloway HR, Everson LI, Griffiths HJ. Peripheral (extra cranial) nerve tumors. Correlation of MR imaging and histological findings. Radiology. 1992;183(2):341–346. 9. Shanbhogue AK, Fasih N, Macdonald DB, Sheikh AM, Menias CO, Prasad SR. Uncommon primary pelvic retroperitoneal masses in adults: a pattern based imaging approach. Radiographics. 2012;32(3):795–817. 10. Nyapathy V, Murthy UK, Chintamani J, Sridhar DY. A case report of a giant presacral cystic schwannoma with sigmoid megacolon. J Radiol Case Rep. 2009;3(12):31–37. 11. Kishi Y, Kajiwara S, Seta S, Kawauchi N, Suzuki T, Sasaki K. Retroperitoneal schwannoma misdiagnosed as a psoas abscess: report of a case. Surg Today. 2002; 32(9):849–852. 12. Ibraheim M, Ikomi A, Khan F. A pelvic retroperitoneal schwannoma mimicking an ovarian dermoid cyst in pregnancy. J Obstet Gynaecol. 2005;25(6):620–621. 13. Santala M, Mosorin M-E, Liakka A. Benign presacral schwannoma mimicking pedunculated leiomyoma. J Turk Ger Gynecol Assoc. 2007;8:90–93.