Giant sacral schwannomas

Rare retroperitoneal giant sacral schwannoma: A case report

Schwannomas localized in the sacrum are relatively infrequent, accounting for 1-5% of all spinal axis schwannomas; they present with vague symptoms or are symptomless, so often grow to a considerable size before detection. Sacral schwannomas occasionally present with enormous dimensions, and these tumors are termed giant sacral schwannomas. However, their surgical removal is challenging owing to an abundant vascularity. The present study retrospectively analyzed the clinical and follow-up data of a patient with a giant sacral schwannoma. The patient experienced numbness in the left buttock and lower extremity, with radiating pain in the sole of the foot that had persisted for 3 years. A presacral mass was found by computed tomography examination 6 months after the stool had become thin. A tumor resection was performed using the anterior abdominal approach. A schwannoma was diagnosed by postoperative pathology. The postoperative course was uneventful, with the complete resolution of symptoms during the 21-month clinical follow-up. Overall, the present study reports the case of a giant sacral schwannoma with pelvic pain that was resected without complications and also discusses its successful management. Additionally, the study presents a systematic review of the literature. We consider that the surgical treatment of giant sacral schwannomas with piecemeal subtotal excision can achieve good outcomes, avoiding unnecessary neurological deficits.

A Rare Case of Melanotic Schwannoma Occurred Intraosseous of Sacrum: A Literature Review

BACKGROUND

Melanotic schwannoma is a rare tumor when it occurs in the sacrum. Though it is mostly classified as benign, the prognosis is unpredictable due to the possibility of recurrence and metastasis. Here, we reported a case of intraosseous of sacrum with good results and reviewed the literature.

CASE PRESENTATION

A 33-year-old male patient complained of low back pain and was discovered to have an obstruction at S2. Following the necessary imaging diagnosis, we treated the patient with piecemeal excision in conjunction with extended curettage, and the frozen biopsy revealed that the tumor was melanotic schwannoma. The intraosseous portion of the lesion was curettaged using high-speed drill to enlarge the edge of curettage, and piecemeal excision for lesion within the sacral canal. After surgery, the patient received total 56Gy radiotherapy and frequent follow-up. After 15 months follow-up, there was no evidence of recurrence, and the nerve function was normal.

CONCLUSION

Melanotic schwannoma that occurs intraosseous of the sacrum is extremely rare and lacks typical clinical manifestations; however it can be identified through careful pathological and imaging diagnosis. Intralesional extended curettage combined with radiotherapy can achieve a good local control with a satisfactory clinical effect in this rare disease.

Surgical management of sacral schwannomas: a 21-year mayo clinic experience and comparative literature analysis

INTRODUCTION

Sacral and presacral schwannomas are rare, accounting for a minority of spinal schwannomas. We present our institution's experience surgically treating spinal schwannomas and compare it to the literature.

METHODS

Data were collected for 27 patients treated surgically for sacral or presacral schwannoma between 1997 and 2018 at all Mayo Clinic locations and 93 patients in the literature. Kaplan-Meier disease-free survival analysis was conducted. Unpaired two-sample t tests and Fisher's exact tests assessed statistical significance between groups.

RESULTS

Our patients and those in the literature experienced a similar age at diagnosis (49.9 y/o. vs 43.4 y/o., respectively). Most of our patients (59.3%) reported full recovery from symptoms, while a minority reported partial recovery (33.3%) and no recovery (11.1%). A smaller percentage in the literature experienced full recovery (31.9%) and partial recovery (29.8%) but also no recovery (1.1%). Our patients experienced fewer complications (14.8% versus 25.5%). Disease-free survival curves for all patients showed no significant variation in progression by extent of resection of schwannoma (log-rank P = 0.26). No lesion progression was associated with full or partial symptom improvement (p = 0.044), and female patients were more likely to undergo resection via a posterior approach (p = 0.042).

CONCLUSION

Outcomes of patients with sacral or presacral schwannomas vary based on patient demographics, tumor characteristics, symptoms, and surgical treatment. Among the range of symptoms experienced by these patients, the most common is pain. Prognosis improves and overall survival is high when the surgical approach towards sacral schwannomas is prepared and executed appropriately.

Giant sacral schwannoma excised under intraoperative neuromonitoring in an elderly patient: case report

Schwannomas are mainly benign tumors arising from the Schwann cells of the peripheral nerve sheath. These tumors can often be associated with non-specific symptoms, such as abdominal heaviness. In this article, we present a detailed description of the surgical management of a giant sacral schwannoma in an elderly patient, for which intraoperative neuromonitoring made it possible to distinguish easily the nerves of the sacral plexus from which the tumor originated and to remove it without complications. Treatment of these rare and symptomatic giant tumors is still a challenge for surgeons; to treat adequately these tumors; a multidisciplinary approach is required to ensure an optimal therapeutic approach to reduce the risk of recurrence and, on the other hand, is not associated with unnecessary iatrogenic neurological damage.

Primary Tumors of the Sacrum: Imaging Findings

The diagnosis of sacral neoplasms is often delayed because they tend to remain clinically silent for a long time. Imaging is useful at all stages of managing sacral bone tumors: from the detection of the neoplasm to the long-term follow-up. Radiographs are recommended as the modality of choice to begin the imaging workup of a patient with known or suspected sacral pathology. More sensitive examinations such as computerized tomography (CT), magnetic resonance (MRI), or scintigraphy are often necessary. The morphological features of the lesions on CT and MRI help to orientate the diagnosis. Although some imaging characteristics are helpful to limit the differential diagnosis, an imaging-guided biopsy is often ultimately required to establish a specific diagnosis. Imaging is of paramount importance even in the long-term follow-up in order to assess any residual tumor when surgical resection is incomplete, to assess the efficacy of adjuvant chemotherapy and radiotherapy, and to detect recurrence.

Management of giant presacral schwannoma. Clinical series and literature review

PURPOSE

Presacral schwannomas are rare tumors. Due to their benign nature and slow growth, these tumors are often giant and become difficult to treat. Their removal is a surgical challenge with different strategies reported in the literature. This study presents the consecutives cases of presacral schwannomas operated on in our institution, our surgical strategy and literature review.

METHODS

This retrospective study includes all consecutive patients operated on for a pre-sacral schwannoma in our department between 2006 and 2019, i.e. 6 patients. We report clinical features, pre and post-operative imaging, surgical data and post-operative outcomes.

RESULTS

All patients had symptoms before surgery (constipation, dysuria, radicular or lower back pain) with an average duration of 7.4 months. All patients underwent an MRI and a CT scan before the surgery. Five patients had type III schwannoma according to Klimo classification and one patient had a type II. The average size was 504,9 cm³ (range 53,1-1495,4). All the patients were operated on by an anterior approach in a double team with an mean duration of 246 min. Intraoperative bleeding was less than 500 ml for 4 patients, 2 patients had significant bleeding (2700 and 2900 mL). Excision was total or subtotal in all cases. One patient had an intraoperative complication (air embolism). Follow up at 3 months was excellent with a disappearance of symptoms for all patients except one patient who retained constipation. One patient had a late complication (bowel obstruction due to tissue adhesions). At last follow-up after phone interview, no patient had clinical symptoms that could suggest a recurrence.

CONCLUSION

The anterior approach with a double surgical team is a great option for the treatment of presacral schwannoma. Combined with adequate preoperative imaging and intraoperative stimulation, it reduces the risk of intra and postoperative complications.

Giant Sacral Schwannoma Causing Bilateral Hydronephrosis: Case Report and Review of the Literature

BACKGROUND

Giant sacral schwannomas are very rare, and less than 1%-5% of spinal schwannomas are found in the sacral region. These frequently grow to considerable size because of permissive anatomic location and benign, slow growth of tumor. They can be unnoticed before reaching a huge size.

CASE DESCRIPTION

We report a rare case of a giant sacral schwannoma in a 46-year-old man. The patient presented with difficulty in passing urine, episodic constipation, and swelling of the right lower extremity for 6 months. Magnetic resonance imaging revealed 160 x 110 x 110 mm encapsulated heterogenous solid mass originated from left S1 spinal nerve extending into the pelvis and abdomen. Sigmoid colon and rectum were displaced to the right side, and bladder was displaced anteriorly. Left side of the S1 and S2 vertebral bodies, left S1 and S2 neural foramen were also eroded. It also compressed ureters causing bilateral hydronephrosis. The patient underwent a 2-stage procedure in which complete resection was achieved.

CONCLUSIONS

We report the second case of a completely resected giant sacral schwannoma with bilateral hydronephrosis in the literature. Performing a 2-stage procedure is important in giant sacral schwannomas. Morbidity can be minimized, and extent of resection can be maximized with the help of combined anterior/posterior approach.

Intraosseous Melanotic Schwannoma in the Sacrum Mimicking Primary Bone Tumor

Primary tumors of sacrum are rarely seen, and the differential diagnosis is extensive, such as chordomas, giant cell tumors, and schwannomas. Sacral intraosseous schwannomas (IOSs) are very rare and encompass approximately 1%–5% of all spinal schwannomas. Melanotic schwannomas (MSs) are categorized as an unusual variant of benign schwannomas; however, they sometimes follow a malignant course. The authors present a case of MS with intraosseous extension into sacrum in a 48-year-old male arising from the left S2 nerve root. Magnetic resonance imaging (MRI) and computed tomography (CT) scan demonstrated a destructive mass in the sacrum. He was made a diagnosis with MS by 18F-fluoro-deoxy-glucose positron-emission-tomography (¹⁸F-FDG PET) and open biopsy. The tumor was blackish-colored and vascular-rich fragile tumor covered by fibrous capsule. The floor of the tumor was not encapsulated and invading into the sacral bone. Total removal of the tumor together with the left S2 nerve of origin via posterior approach was achieved. The patient made dramatic recovery of neurological symptoms and tumor recurrence is not seen for 6-month follow-up period. MS is a benign tumor with potential for aggressive behavior and capacity to metastasize. Therefore, total removal of the tumor and careful postoperative follow-up are recommended. Postoperative spinopelvic stability also needs to be taken into consideration. The authors discuss our successful management with a focus on diagnostic process, surgical planning, and histological consideration to provide the most up-to-date guidance on managing this challenging tumor.

Perineal and Radicular Pain Caused by Contralateral Sacral Nerve Root Schwannoma: Case Report and Review of Literature

BACKGROUND

Sacral schwannomas are very rare nerve sheath tumors. Patients usually present with a variety of nonspecific symptoms, which often lead to a delay in diagnosis. Although most schwannomas are benign, they present surgical challenges owing to their proximity to neurologic and other anatomic structures.

CASE DESCRIPTION

This 58-year-old female presented with a 2-month old history of left-sided perineal and radicular pain secondary to a right S2 sacral nerve root schwannoma. The sacral mass demonstrated homogenous enhancement with cystic changes in a T2-weighted magnetic resonance imaging sequence. The patient underwent S1-S3 laminectomy and tumor excision through a posterior surgical approach. Intraoperative monitoring was used to distinguish nonfunctional tissue during tumor resection. The patient had an unremarkable postoperative course.

CONCLUSIONS

Sacral schwannomas can present with a variety of nonspecific symptoms. They pose unique challenges given their location, size, and involvement of surrounding structures. Complete surgical resection is the main goal of sacral schwannoma treatment. A combined anterior-posterior surgical approach and a multidisciplinary surgical team are associated with improved outcomes.

Clinical features and surgical treatment of sacral schwannomas

BACKGROUND

Sacral schwannoma is relatively rare and both the early diagnosis and appropriate treatment of sacral schwannomas are equally very challenging.

METHODS

11 sacral schwannoma cases operated at the Second Affiliated Hospital, School of Medicine, Zhejiang University, from 2012 to 2016, were investigated retrospectively and 10 were followed up. All patients were assessed with X-ray, CT and MRI, and underwent an intralesional excision.

RESULTS

One patient was male, nine were female and the average age was 48 (ranging between 31 and 63). Three patients suffered from back and leg pain, and seven had no obvious symptoms. The average blood loss during surgery was 980ml (ranging between 100 and 2,000ml). Six patients underwent preoperative biopsy. The surgeries were performed via the combination of an anterior and posterior approach in two patients, a posterior approach in seven patients, and an anterior approach in one patient. Residual tumors were not detected in all patients after surgery. Unfortunately, the postoperative complications occurred in three patients, namely bowel and bladder dysfunction (two patients) and cerebrospinal fluid leakage with secondary intracranial infection (one patient). The average follow-up was 22.7 months (8-44 months). All patients were relieved from preoperative symptoms after the last follow-up.

CONCLUSIONS

The typical findings of our cases in MRI were a well-circumscribed lesion with a heterogenous signal intensity on T2-weighted image, which may be helpful for preoperative decision-making. Intralesional excision can be successfully performed using single anterior or single posterior or both, and is an important procedure in the treatment of sacral schwannomas.

Tumors of the peripheral nervous system: analysis of prognostic factors in a series with long-term follow-up and review of the literature

OBJECT

Only a few published studies of the surgical treatment of benign peripheral nerve sheath tumors (BPNSTs), malignant peripheral nerve sheath tumors (MPNSTs), and peripheral non–neural sheath tumors (PNNSTs) have analyzed the results and possible prognostic factors using multivariate analysis. The authors report on their surgical series of cases of BPNSTs, MPNSTs, and PNNSTs with long-term follow-up and analyze the role of selected factors with respect to the prognosis and risk of recurrence of these tumors using multivariate analysis. They also review the pertinent literature and discuss their results in its context.

METHODS

The authors retrospectively reviewed data from cases involving patients who underwent resection of a peripheral nerve tumor between January 1983 and December 2013 at their institution. Of a total of 200 patients, 150 patients (with 173 surgically treated tumors) had adequate follow-up data available for analysis. Pain was assessed using a visual analog scale (VAS), and motor and sensory function were assessed by means of the Louisiana State University grading system. They also analyzed the relationship between tumor recurrence and patient sex, patient age, diagnosis of neurofibromatosis (NF), tumor histopathology, tumor size, tumor location, and extent of resection (subtotal vs gross-total resection), using univariate and multivariate analyses.

RESULTS

There was a statistically significant improvement in the mean VAS pain score (preoperative 3.96 ± 2.41 vs postoperative 0.95 ± 1.6, p = 0.0001). Motor strength and sensory function were significantly improved after resection of tumors involving the brachial plexus (p = 0.0457 and p = 0.0043, respectively), tumors involving the upper limb (p = 0.0016 and p = 0.0016, respectively), BPNSTs (p = 0.0011 and p < 0.0001, respectively), and tumors with dimensions less than 5 cm (motor strength: p = 0.0187 and p = 0.0021 for ≤ 3 cm and 3–5 cm tumors, respectively; sensory function: p = 0.0003 and p = 0.0001 for ≤ 3 cm and 3–5 cm tumors, respectively). Sensory function showed a statistically significant improvement also in patients who had undergone resection of tumors involving the lower limb (p = 0.0118). Total resection was associated with statistically significant improvement of motor strength (p = 0.0251) and sensory function (p < 0.0001). In univariate analysis, a history of NF (p = 0.0034), a diagnosis of MPNST or PNNST (p < 0.0001), and subtotal resection (p = 0.0042) were associated with higher risk of tumor recurrence. In multivariate analysis (logistic regression analysis), a history of NF (OR 9.28%, 95% CI 1.62–52.94, p = 0.0121) and a diagnosis of MPNST (OR 0.03%, 95% CI 0.002–0.429, p = 0.0098) or PNNST (OR 0.081%, 95% CI 0.013–0.509, p = 0.0077) emerged as independent prognostic factors for tumor recurrence.

CONCLUSIONS

A total resection should be attempted in all cases of peripheral nervous system tumors (irrespective of the supposed diagnosis and tumor dimensions) because it is associated with better prognosis in term of functional outcome and overall survival. Moreover, a total resection predicts a lower risk of tumor recurrence. Patients with a history of NF and tumors with malignant histology remain a challenge both for neurosurgeons and oncologists due to higher recurrence rates and the lack of standardized adjuvant therapies.

Giant cystic sacral schwannoma mimicking tarlov cyst: a case report

PURPOSE

To present a rare case of a giant schwannoma of the sacrum mimicking a Tarlov cyst.

METHODS

A 58-year-old woman had a 1-year history of low back pain. MRI revealed a large cystic mass in the sacral canal with bony erosion. Radiological diagnosis of Tarlov cyst was made.

RESULTS

The patient underwent surgical treatment for the lesion, which revealed a solid mass. Histopathological examination of the tumor confirmed the diagnosis of schwannoma. The postoperative course was uneventful and the patient has had significant improvement in her pain 1 month postoperatively.

CONCLUSION

Giant cystic schwannoma of the sacrum is a very rare diagnosis overlooked by practitioners for more common cystic etiologies, but its treatment is significantly different. Care should be taken to include this diagnosis in a differential for a cystic sacral mass.

Schwannomas and their pathogenesis

Schwannomas may occur spontaneously, or in the context of a familial tumor syndrome such as neurofibromatosis type 2 (NF2), schwannomatosis and Carney's complex. Schwannomas have a variety of morphological appearances, but they behave as World Health Organization (WHO) grade I tumors, and only very rarely undergo malignant transformation. Central to the pathogenesis of these tumors is loss of function of merlin, either by direct genetic change involving the NF2 gene on chromosome 22 or secondarily to merlin inactivation. The genetic pathways and morphological features of schwannomas associated with different genetic syndromes will be discussed. Merlin has multiple functions, including within the nucleus and at the cell membrane, and this review summarizes our current understanding of the mechanisms by which merlin loss is involved in schwannoma pathogenesis, highlighting potential areas for therapeutic intervention.

Cystic giant sacral schwannoma mimicking aneurysmal bone cyst : a case report and review of literatures

To present a rare case of a cystic giant schwannoma of the sacrum mimicking aneurysmal bone cyst (ABC). A 54-year-old man visited our institute complaining left leg weakness and sensory change for several years. Magnetic resonance imaging revealed a large multilocular cystic mass with canal invasion and bone erosion confined to left S1 body. The lesion showed multiple septal enhancement without definite solid component. Initially the tumor was considered as ABC. The patient underwent grossly-total tumor resection with lumbosacral reconstruction via posterior approach. The tumor was proved to be a cystic schwannoma. The postoperative course was uneventful and the patient was relieved from preoperative symptoms. We present a rare case of pure cystic giant schwannoma confined to sacrum mimicking ABC. The surgical treatment is challenging due to the complex anatomy of the sacrum. Schwannoma should be considered in the differential diagnosis of osteolytic sacral cysts.

Differentiation of primary chordoma, giant cell tumor and schwannoma of the sacrum by CT and MRI

OBJECTIVE

To evaluate criteria to differentiate sacral chordoma (SC), sacral giant cell tumor (SGCT) and giant sacral schwannoma (GSS) with CT and MRI.

MATERIALS AND METHODS

CT and MR images of 22 SCs, 19 SGCTs and 8 GSSs were reviewed. The clinical and imaging features of each tumor were analyzed.

RESULTS

The mean ages of SC, SGCT and GSS were 55.1 ± 10.7, 34.3 ± 10.7 and 42.4 ± 15.7 years old. SCs (77.3%) were predominantly located in the midline of lower sacrum, while most SGCTs (73.7%) and GSSs (87.5%) were eccentrically located in upper sacrum. There were significant differences in age, location, eccentricity, morphology of bone residues, intratumoral bleeding and septations. Multiple small cysts were mainly observed in SGCTs (73.7%) with large central cysts in GSSs (87.5%). SGCTs expanded mainly inside sacrum while SCs and GSSs often extended into pelvic cavity (P = 0.0022). Involvement of sacroiliac joints and muscles were also different. Ascending extension within sacral canal was only displayed in SCs. The preservation of intervertebral discs showed difference between large and small tumors (P = 0.0002), regardless of tumor type (P = 0.095). No significant difference was displayed in gender (P = 0.234) or tumor size (P = 0.0832) among three groups.

CONCLUSION

Age, epicenter of the lesion (midline vs. eccentric and upper vs. lower sacral vertebra), bone residues, cysts, bleeding, septation, expanding pattern, muscles and sacroiliac joint involvement can be criteria for diagnosis. Fluid-fluid level is specific for SGCTs and ascending extension within the sacral canal for SCs. The preservation of intervertebral discs is related to tumor size rather than tumor type.