| "text": "This is an academic paper. This paper has corpus identifier PMC2528062\nand Review of Literature\n\nAUTHORS: Chandhanarat Chandhanayingyong, Apichat Asavamongkolkul, Nittaya Lektrakul, Sorranart Muangsomboon\n\nABSTRACT:\nSacral schwannoma is a rare retrorectal tumor in adults. Postoperative sacral neurological deficit is difficult to avoid. Currently, there is no established consensus regarding best treatment options. We present the management and outcomes of sacral schwannoma in 4 patients treated with intralesional curettage and postoperative radiation. There were 3 women and one man (average age: 45.5 years) with long duration of lumbosacral pain with or without radiculopathy. Intralesional curettage was performed by posterior approach and adjuvant radiation therapy with dosage of 5000–6600 cGy was given after surgery. The mean follow-up time was 18 months (range 4–23 months). Symptoms of radiculopathy had decreased in all patients. The recent radiographic findings show evidence of sclerosis at the sacrum one year postoperatively, but the size was unchanged. Intralesional curettage and adjuvant radiation therapy can be used in the treatment of sacral schwannoma to relieve symptoms and preserve neurological function.\n\nBODY:\n1. INTRODUCTIONSchwannoma is a benign neoplasm of schwann cell, arising\nalong sensory nerve roots in the extremities and upper thorax. These tumors rarely arise within bone, among\nwhich mandible and sacrum are the most common sites of involvement. Only 79\nintraosseous schwannomas have been reported in English literature and 21 were\nlocated at the sacrum [1]. Most of the cases were treated by curettage and\noverall results were favorable due to preservation of sacral nerve roots [1–14].\nHowever, the rate of local recurrence was reported to be relatively high (54\npercent) when treated by conservative means. Abernathey et al. suggested wide\nexcision of sacral schwannoma to prevent tumor recurrence [6]. Many authors reported that sacral amputation\nand lumbopelvic fixation allowed total removal of sacral schwannoma\n[4, 6–14]. The patients who were treated with sacral\namputation had greater chance of having postoperative bowel and bladder\ndysfunction, in addition to decreased sensation and motor weakness of lower\nextremities due to sacral nerve roots injury. Excision of the tumor might cause\nextensive blood loss from combined anterior and posterior approaches. The surgical\ntechnique is needed\nand instrumentation is required to maintain spinal stability. Even though\nattempts to minimize such complications were done by laparoscopic or gamma knife\nsurgery, the results are still in their study periods and only a limited number\nof cases were included [15–19]. We report a series of 4 cases\nof sacral schwannoma treated by intralesional curettage and postoperative\nradiation therapy. Relatively conservative methods were used due to the benign\ncondition of the tumor. The clinical outcomes and sequential radiographic\nresults are presented.2. PATIENTS AND METHODSBetween July 2005 and March 2008, three women and one man\nwith sacral schwannoma were treated in our institute. Mean age of the patients was 45.5 years (range\n29–62 years). All\npatients presented with lumbosacral pain, of duration from 8 months to six\nyears (mean 3.4 years). Three patients complained of pain that later progressed\nto sciatica and dysethesia of one or both legs. One of them developed\ndifficulty in urination and also had constipation. Neurological examination of patient no. 2\nrevealed no lower extremity weakness, but decreased deep tendon reflex of the left\nankle joint, and diminished left anterior thigh and perianal sensation. The other three patients present no\nneurological deficit except a loss of sensation in the left great toe in\npatient no. 3 (Table 1).Plain radiographic findings showed an extensive osteolytic\nlesion with sclerotic border which involved the whole sacrum of two patients\n(nos. 2 and 4) (Figure 1) and only an ill-defined osteolytic lesion mainly\noccupying the left side of S2-3 area in the other two patients (nos. 1 and 3). MRI revealed iso-intensity to hypointensity\nimaging on T1-weighted sequence and hyperintensity imaging on T2 weighted in\nall patients. Mean maximal length of the\ntumor was 8.1 cm (range 4.4–11.0 cm) and mean volume was 259.8 cm3 (range 50.6–770.0 cm3).\nThe tumor extended into surrounding tissue and displaced abdominal structures\nanteriorly in two patients (nos. 2, 4), but the fat plain between tumor and\nabdominal cavity was evidenced in all cases \n(Figure 2). This finding indicated that there was no tumor invasion into\ninternal organs. In one patient (no. 1),\nthe tumor expanded only posteriorly and compressed the dural sac, with multicystic\nlesions (Figure 3). All MRI findings\ndemonstrated tumor extension from neural foramen (Figure 4), and one was seen\nas a dumbbell-shaped configuration (Figure 5). This appearance clarified by tumor\narising within the sacral foramina as the narrowest part and expanded\nintrasacral and displaced pelvic organs anteriorly, which could be seen in axial\nMR imaging.In all patients, intralesional curettage was performed by\nposterior approach through sacral laminectomy. The tumor capsule remained\nintact. Two tumors were intrasacrally confined and 2 extended extrasacrally,\nbut all were extradural. Intraoperative\nnerve stimulators were not performed. After tumor removal, lumbosacral and\nsacroiliac stability of all patients was not changed. No reconstruction and\ninstrumentation was performed in any patients. Histological finding showed\ntypical schwannoma in all 4 cases. There\nwas no appearance of degenerated neurilemmoma (ancient schwannoma) or\nhypercellular tumor (cellular schwannoma) in this series.After the wounds had healed at six to eight weeks, radiation\ntherapy was performed in the out-patient clinic using dosage of 5000–6600 cGy.3. RESULTSAt the mean follow-up time of 18 months, all patients\nexperienced relief of lumbosacral and radicular pain after surgery. Urinary hesitancy was improved in patient no.\n2. Perianal sensation was subsequently improved at six months\npostoperatively. No neurological\nworsening occurred in any patients. No\nrecurrent symptoms were evidenced afterward. \nThe patients could walk well without gait aids.Plain radiographs showed marginal sclerosis at the lesion and\ndestruction of the sacrum had not progressed (Figure 6). \nOnly patient no. 2 showed a nondisplaced\nfracture of S2 on the left side as a result of preoperative massive bony\ndamage. MRIs were performed two months after surgery and revealed that tumors\nwere eradiated resulting as cystic portion, but two patients demonstrated small\namount of residual tumor (Table 1). The presacral cysts were persistent in the\nsame size as before surgery. Although\nthe cystic lesion did not disappear, its progress was stopped by radiation.Patient no. 2 had amenorrhea permanently after radiation. She\nwas counseled earlier and decided to have radiation therapy due to the large\nsize of the tumor and a postoperative residual tumor that was evidenced through\nMRI.4. DISCUSSIONOf all malignant tumors originating in sacrum, chordomas,\nchondrosarcoma, and metastatic lesions are most frequently observed. Benign sacral lesions including giant cell\ntumor, aneurysmal bone cyst, and osteoblastomas are occasionally evidenced\nwhereas schwannomas are very rare [20]. There is no sex predilection in this tumor [1, 4, 6, 13, 21, 22]. although in our series male\nfemale ratio was 1:3. Lumbosacral pain with or without radiculopathy were the\nmost frequent symptoms noted in previous studies and in our patients. Decrease\nin lower extremity sensation is the most frequent neurological sign found. A tumor\nwhich was confined in a more proximal spinal level would cause early seeking of\nmedication and result in earlier detection than a tumor which is contained in the\nlower spinal level [3, 13]. In the same way, tumor extension posteriorly\nto dural sac and nerve roots would be earlier symptomatic than a tumor which\nextends anteriorly adjacent to abdominal structure.Plain radiograph of the lumbosacral area often fail to be noticed\nespecially when the lesion is undersize. CT is useful to detect degree of bony\ndestruction, but an MRI provides a better display in multiple views of the\nsacral mass. In all of our patients, MRI\nwere performed and demonstrated details of intrasacral, intrapelvic, intra- or\nextradural, and nerve root compression, as well as displaying the relationship\nto neighboring structures. This information aids in preoperative diagnosis and\nsurgical management.Many studies in surgical treatment for sacral schwannoma have\nbeen reported. Abernathey et al. reported 13 cases of schwannoma of the sacrum [6]. Nine patients in this study who were treated\nby intralesional curettage experienced tumor recurrence and underwent\nadditional surgery (54 percent) with follow-up periods ranging from 5 months to\n33 years (mean 9 years). Their study suggested that schwannoma originating in\nthe sacrum should be aggressively resected with the aim of complete extirpation\nand that sacrifice of all or many nerve roots was required to minimize the risk\nof recurrence. In contrast, Dominguez et al. reassured us that a conservative approach\nwith intracapsular enucleation\nalone produced a favorable result of only 16 percent recurrence rate [1]. The follow-up period was\nrange from 18 months to 21 years (average 9.2 years). The follow-up time of our\nseries might be too early to conclude that, though we used a conservative\napproach, the recurrence rate was 0 percent with a follow-up period of 7 months\nto 27 months (mean 18 months).Role of adjuvant radiation therapy is controversial. Kotoura et al. presented one case that was\ntreated with intralesional curettage and adjuvant radiation therapy [23]. The attempt was made to preserve nerve roots\nas much as possible. The patient was followed up for 5 years, and plain\nradiograph and CT scan showed arrest of the tumor with marginal sclerosis. However,\nFeldenzer et al. revealed that the tumor did not respond at all [24]. Conventionally, radiation therapy is avoided\nin the treatment of benign tumors, because of the risk of secondary\ncarcinogenesis [25]. However, radiation therapy is obligatory in\nsome cases in which anatomic location of the tumor does not allow total\nextirpation, or in which aggressive resection may cause serious functional\ndamage. It has been reported that cases of giant cell tumor at the lumbosacral\narea can be controlled by radiotherapy [26–28].For benign tumors at this particular location, the patients\nhave minimal risk of distant metastasis, low rate of recurrence, and excellent\nprognosis. It is desirable to preserve the functions of lower extremities, as\nwell as bowel and bladder function after the treatment.5. CONCLUSIONSThis is a report of a rare clinical entity. Although the number of the patients and the\nlength of follow-up are limited, we made the conclusions as the followings.\nClinical courses were longer in the patient who had anterior tumor extension\nand lower level of spinal involvement (average 4.3 years) than posterior\nextension and upper level of spinal involvement (8 months) which compress the dural\nsac and sacral nerve root more rapidly. But when compared to tumors in other regions,\nthe duration is still extremely long. The symptoms of radicular pain, loss of\nmotor power, decreased sensation of lower extremities, and bowel bladder\nsymptoms would subsequently occur after time. \nMRI is an important diagnostic tool because plain X-ray films of the\nlumbosacral area are often inconclusive. \nThe tumors always originate from one side of the sacral foramen and\nextend to the adjacent structures, and are recognized as having a dumbbell\nshape. This finding is useful for preoperative diagnosis. 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