Retroperitoneal schwannoma

Retroperitoneal pelvic schwannoma: A rare case report and review of the literature

Schwannoma, typically a non-cancerous tumor originating from Schwann cells, seldom occurs in the retroperitoneal area. Its clinical manifestation varies, often remaining asymptomatic for an extended period until it enlarges, exerting pressure on neighboring organs. This article presents a unique instance of retroperitoneal pelvic schwannoma in a 75-year-old woman, initially presenting with unusual lower back discomfort. Imaging was used to characterize the tumor, and anatomopathological examination established the preoperative diagnosis of pelvic schwannoma and its benign nature. The clinical, imaging, and anatomopathological aspects of this pelvic schwannoma case are elucidated herein.

Imaging in gynecological disease (26): clinical and ultrasound characteristics of benign retroperitoneal pelvic peripheral-nerve-sheath tumors

OBJECTIVE

To describe the clinical and sonographic characteristics of benign, retroperitoneal, pelvic peripheral-nerve-sheath tumors (PNSTs).

METHODS

This was a retrospective study of patients with a benign, retroperitoneal, pelvic PNST who had undergone preoperative ultrasound examination at a single gynecologic oncology center between 1 January 2018 and 31 August 2022. All ultrasound images, videoclips and final histological specimens of benign PNSTs were reviewed side-by-side in order to: describe the ultrasound appearance of the tumors, using the terminology of the International Ovarian Tumor Analysis (IOTA), Morphological Uterus Sonographic Assessment (MUSA) and Vulvar International Tumor Analysis (VITA) groups, following a predefined ultrasound assessment form; describe their origin in relation to nerves and pelvic anatomy; and assess the association between their ultrasound features and histotopography. A review of the literature reporting benign, retroperitoneal, pelvic PNSTs with preoperative ultrasound examination was performed.

RESULTS

Five women (mean age, 53 years) with a benign, retroperitoneal, pelvic PNST were identified, four with a schwannoma and one with a neurofibroma, of which all were sporadic and solitary. All patients had good-quality ultrasound images and videoclips and final biopsy of surgically excised tumors, except one patient managed conservatively who had only a core needle biopsy. In all cases, the findings were incidental. The five PNSTs ranged in maximum diameter from 31 to 50 mm. All five PNSTs were solid, moderately vascular tumors, with non-uniform echogenicity, well-circumscribed by hyperechogenic epineurium and with no acoustic shadowing. Most of the masses were round (n = 4 (80%)), and contained small, irregular, anechoic, cystic areas (n = 3 (60%)) and hyperechogenic foci (n = 5 (100%)). In the woman with a schwannoma in whom surgery was not performed, follow-up over a 3-year period showed minimal growth (1.5 mm/year) of the mass. We also summarize the findings of 47 cases of benign retroperitoneal schwannoma and neurofibroma identified in a literature search.

CONCLUSIONS

On ultrasound examination, no imaging characteristics differentiate reliably between benign schwannomas and neurofibromas. Moreover, benign PNSTs show some similar features to malignant retroperitoneal tumors. They are solid lesions with intralesional blood vessels and show degenerative changes such as cystic areas and hyperechogenic foci. Therefore, ultrasound-guided biopsy may play a pivotal role in their diagnosis. If confirmed to be benign PNSTs, these tumors can be managed conservatively, with ultrasound surveillance. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Integrated Neurosurgical Management of Retroperitoneal Benign Nerve Sheath Tumors

Peripheral nerve sheath tumors (PNST) of the retroperitoneum are rare and are often treated by general surgeons dealing with retroperitoneal cancers. However, resection without the correct microsurgical technique can cause permanent neurological deficits and pain. Here, we discuss our interdisciplinary approach based on the integration of expertise from neurosurgery and abdominal surgery, allowing for both safe exposure and nerve-sparing microsurgical resection of these lesions. We present a series of 15 patients who underwent resection of benign retroperitoneal or pelvic PNST at our institution. The mean age of patients was 48.4 years; 67% were female. Tumors were 14 schwannomas and 1 neurofibroma. Eight patients (53%) reported neurologic symptoms preoperatively. The rate of complete resection was 87% (n = 13); all symptomatic patients showed improvement of their preoperative symptoms. There were no postoperative motor deficits; one patient (7%) developed a permanent sensory deficit. At a mean postoperative follow-up of 31 months, we observed no recurrences. To our best knowledge, this is the second-largest series of benign retroperitoneal PNST consistently managed with microsurgical techniques. Our experience confirms that interdisciplinary management allows for safe treatment of these tumors with good neurological and oncological outcomes.

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.

Retroperitoneal schwannoma sandwiched between abdominal aorta and inferior vena cava. A case report

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Retroperitoneal schwannomas in the abdominal cavity are rare and pose difficulty in preoperative diagnosis and management.

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Imaging modalities are usually not sufficient to conclude a diagnosis.

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EUS-FNA is useful to confirm preoperative diagnosis.

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In EUS-FNA, diagnosis can be accurate if the tumor size is small and tumor is devoid of intratumoral degenerations.

Introduction

Schwannomas are tumors that originate from the Schwann cells present in the nerve sheath of peripheral nerves. They are commonly seen in cephalocervical areas. Schwannomas in the abdominal cavity are rare. Here, we discuss a case of retroperitoneal schwannoma lying dorsal to pancreas with critical relations to surrounding vessels.

Presentation of case

A 74 years old asymptomatic male was found with elevated amylase level on his routine blood examination. MR imaging revealed retroperitoneal mass of size 21*18*24 mm. EUS-FNA confirmed retroperitoneal schwannoma. The patient had co-morbid renal disease and was on hemodialysis. During the latest follow up, the tumor was 41*37*41 mm in size located dorsal to the confluence of right renal vein and inferior vena cava. The tumor was in contact with inferior vena cava, horizontal part of duodenum, right renal artery, right kidney, and adrenal gland. The patient underwent laparotomy and the tumor was extract with intact capsule. There were no post-operative complications.

Discussion

Pre-operative diagnosis in retroperitoneal schwannomas is challenging because imaging features are usually non-specific, and biopsy is the only diagnostic technique. EUS-FNA, which has low diagnostic accuracy, is useful in pre-operative diagnosis of small tumors devoid of intra-tumoral degeneration.

Conclusion

Retroperitoneal schwannoma is a rare entity. Preoperative diagnosis and curative resection are technically difficult. Care should be given during preoperative investigations and surgical resection of the tumor. EUS-FNA can be a useful diagnostic tool.

Retroperitoneal schwannoma mimicking an adnexal mass in pregnancy

A 36-year-old pregnant woman attended her first trimester scan and there was an incidental finding of a right-sided complex cystic adenexal mass. Further investigations including repeat pelvic ultrasound scans and MRI were performed due to its complex nature but were inconclusive. Multidisciplinary team review of images found the mass to be retroperitioneal, neurogenic in origin and involving the L5 vertebrae. The pregnancy continued to term and the baby was delivered at 39 weeks gestation by elective caesarean section due to the mass being likely to obstruct progress in labour. Postnatal biopsy confirmed a schwannoma. Plans were made for resection however as the woman was asymptomatic she declined surgery in favour of completing her family. She conceived again 2 years later and a second pregnancy was managed in the same way. The size of the schwannoma remained stable throughout this period.

Sonographic appearances of adrenal schwannomas

OBJECTIVE

To evaluate the sonographic ultrasound (US) appearances of adrenal gland schwannomas.

MATERIALS AND METHODS

This was a retrospective analysis of 15 cases of schwannomas involving the adrenal gland. The following US features were assessed: size, border, echogenicity, homogeneity, intralesional cystic necrosis, presence of septa, intralesional calcification, posterior acoustic enhancement and blood supply.

RESULTS

Of the 15 tumors, seven (46.7%) were located on the left side, and the remaining eight (53.3%) on the right side. The most frequent US appearance of adrenal schwannoma was a single, well-defined and isoechoic mass. The internal echotexture was homogeneous in 2 cases, and heterogeneous in 13 cases, with intralesional cystic areas (n = 11), septa (n = 10) or calcifications (n = 6). Posterior acoustic enhancement was seen in 12 of the 15 cases (80%). On color Doppler US, 86.7% (13/15) of the lesions did not show any vascularity.

CONCLUSIONS

Adrenal schwannomas usually present on US as well-defined isoechoic masses often with posterior acoustic enhancement, cystic necrosis with septa and poor blood supply. These appearances should suggest the diagnosis of adrenal schwannomas. Nevertheless, additional information from laboratory tests and CT or MR imaging may be required to avoid unnecessary surgery.

MR imaging features of benign retroperitoneal paragangliomas and schwannomas

Background

To determine whether MRI feature analysis can differentiate benign retroperitoneal extra-adrenal paragangliomas and schwannomas.

Methods

The MRI features of 50 patients with confirmed benign retroperitoneal extra-adrenal paragangliomas and schwannomas were retrospectively reviewed by two radiologists blinded to the histopathologic diagnosis. These features were compared between two types of tumours by use of the Mann-Whitney test and binary logistic regression. The patients’ clinical characteristics were reviewed.

Results

Analysis of MRI images from 50 patients revealed no significant differences in the quantitative MRI features of lesion size, ratio of diameter and apparent diffusion coefficient. There were significant differences in the qualitative MRI features of location, necrosis, cysts and degree of tumour enhancement for two readers, with no significant differences in the other qualitative MRI features between these tumours. The combination of necrosis with degree of tumour enhancement during the arterial phase increased the probability that a retroperitoneal mass would represent retroperitoneal extra-adrenal paraganglioma as opposed to schwannoma.

Conclusion

We have presented the largest series of MRI features of both benign retroperitoneal extra-adrenal paragangliomas and schwannomas. Some MRI features assist in the differentiation between these tumours, with imaging features consisting of necrosis and avid enhancement during the arterial phase, suggestive of retroperitoneal extra-adrenal paragangliomas.

Laparoscopically resected obturator nerve schwannoma: A case report

Obturator nerve schwannomas are very rare. To date, only nine cases have been reported in the English-language literature; none of these were diagnosed preoperatively. A 68-year-old woman was admitted with left lower abdominal pain. CT and MRI revealed a mass 30 mm in diameter in the left obturator fossa, suggesting a retroperitoneal tumor. Because CT and MRI revealed clear continuity with the left obturator nerve, this case was diagnosed as an obturator nerve schwannoma. Tumor enucleation was performed by laparoscopy. On histopathological examination, this case was diagnosed as a benign obturator nerve schwannoma. Postoperatively, the patient developed weakness of the adductor muscle but recovered within 6 months with rehabilitation therapy. Preoperative diagnosis of obturator nerve schwannomas is quite difficult, but careful inspection of CT and MRI is important to identify the original nerve of schwannoma preoperatively. Accordingly, laparoscopic resection is a good treatment option.

Preoperative management of giant retroperitoneal schwannoma: A case report and review of the literature

Schwannomas rarely occur in the retroperitoneum, and are normally not aggressive. Preoperative diagnosis is difficult and the surgeon may confront blood vessels, nerves or organs damage, since the intra-operative findings are various. The diagnosis and treatment of malignant schwannomas in the retroperitoneum are even more challenging. In addition, the prognosis of malignant schwannomas is extremely poor. The present study reports the case of a 52-year-old woman who presented with a 6-month history of an abdominal mass in the left lower quadrant. The local doctor determined a preliminary diagnosis of abdominal giant tumor and referred the patient to the First Affiliated Hospital, Medical School of Xi'an Jiaotong University, (Xi'an, China). Following discussion, the patient underwent a surgical resection. Low-grade malignant schwannoma was diagnosed following histological examination. No evidence of recurrence or any other complication was observed at the 18-month follow-up examination. The present study reports a case of giant retroperitoneal schwannoma (RS), and includes a literature review in order to provide an overview of the diagnosis, treatment and prognosis of RS and discuss preoperative management strategies for the disease.

Myxoid adrenocortical adenoma: magnetic resonance imaging and pathology correlation

We report a case of a 74-year-old female with myxoid adrenocortical adenoma which showed different magnetic resonance imaging findings compared to those of a typical adrenocortical adenoma. The myxoid change in the adrenocortical adenoma is a rare form of degeneration. It presents a considerable diagnostic challenge to both radiologists and clinicians because it can mimic other adrenal tumor types on imaging. The MRI findings of the presented case included a high signal intensity on T2-weighted images similar to that of fluid and delayed progressive enhancement.

Giant intraosseous schwannoma of scapula: a rare case report and review of the literature

Bony schwannoma is a rare benign tumor derived from schwann cells of nerve fibers in the bone. It accounts for less than 1% of bony benign tumor, and prone to occur in the sacrum and mandible, occurrence in scapula is very rare. Here we report a 42-year-old woman with the chief complaint of pain in the left scapula. Imaging examination showed a giant, irregular, swelling lesion with distinct border involving the left scapula, extending into the left shoulder glenoid and pressing the surrounding soft tissues. Needle biopsy showed that the tumor was composed of spindle cells with S-100 protein positive, mimicking a benign neurogenic tumor. Then a complete excision was performed by removing the tumor and the surrounding tissues including partial left shoulder glenoid. Histologically, Antoni type A areas were the predominant microscopic pattern with occasional alternation by Antoni type B areas. Immunohistochemistry found that the neoplastic cells were scatteredly positive for S-100 protein. All these features suggest a diagnosis of an intraosseous schwannoma of the left scapula. Follow-up of the patient for ten months found no recurrence or sign of other tumors following complete tumor resection without any adjuvant therapy. In conclusion, this case of giant intraosseous schwannoma of the scapula is a rare benign bony tumor, and its diagnosis combined with clinical, imaging and pre-operative needle biopsy is important to guide further therapy, and avoid overtreatment.

CT and MR imaging of retroperitoneal schwannoma

The purpose of this presentation is to allow the radiologist to discuss the diagnosis of retroperitoneal schwannoma, involving mostly a fortuitous discovery and a misleading clinical presentation. We present 4 cases of retroperitoneal schwannoma, two having benefited from a surgery and two others of a therapeutic abstention. The retropritoneal localization and the imaging are good indicator elements of this pathology. The constant improvement of the CT and MR imaging allows a better approach of this entity also by specifying its localization and its anatomical relationships to guide the therapeutic attitude which must be remain mutidisciplinary.

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.

Retroperitoneal schwannomas in the anterior pararenal space: dynamic enhanced multi-slice CT and MR findings

BACKGROUND

To evaluate the imaging features of schwannomas in the anterior pararenal space (APS), especially focusing on dynamic enhanced multi-slice CT (MSCT) and MR findings.

PATIENTS AND METHODS

Eight patients with pathologically proved retroperitoneal schwannomas in the APS underwent dynamic enhanced multi-slice CT (MSCT), while three of these patients also had a contrast-enhanced MR examination. The imaging findings were retrospectively reviewed.

RESULTS

All eight cases exhibited forward displacement of the pancreas, and three cases showed lateral displacement and compression of the inferior vena cava. The tumors had round or oval shape with a maximal axial diameter of 4.0-12.3 cm (average, 6.7 cm). All eight tumors were solitary and well circumscribed. Of the eight retroperitoneal schwannomas in the APS, six exhibited a capsule with thickness of 1.0-2.0 mm, one showed punctate calcification, two displayed cystic degeneration, and three revealed a "target sign" on CT and MR. The tumors were hypo-dense on unenhanced CT images, hyper-intense on T2W images, and homogeneously hypo-intense on T1W images. All eight tumors exhibited gradual enhancement on dynamic enhanced CT or MR images. One case showed delayed enhancement. Heterogeneous enhancement was the dominant pattern occurring in seven out of eight tumors.

CONCLUSION

The imaging findings of schwannoma in the APS correspond with its pathological composition. Schwannoma should be included in the differential diagnosis of tumors in the APS.

Laparoscopic resection of an adrenal schwannoma

BACKGROUND AND OBJECTIVES

Schwannomas are tumors originating from Schwann cells of the peripheral nerve sheath (neurilemma) of the neuroectoderm. Rarely, schwannomas can arise from the retroperitoneum and adrenal medulla. We describe a case of a 71-y-old woman who presented with an incidentally discovered adrenal tumor.

METHODS

Ultrasound and computed tomography scans revealed a lesion with solid and cystic areas originating from the left adrenal gland. The patient underwent complete laparoscopic resection of the tumor and the left adrenal gland.

RESULTS

Histopathological examination and immunohistochemical staining of the excised specimen revealed a benign schwannoma measuring 5.5×5 3.7 cm. To our knowledge, few other cases of laparoscopic resection of adrenal schwannomas have been reported.

CONCLUSION

Because preoperative diagnosis of adrenal tumors is inconclusive, complete laparoscopic excision allows for definitive diagnosis with histological evaluation and represents the treatment of choice.

Misdiagnosis of retroperitoneal schwannoma: A retrospective study of 20 cases

AIM: To investigate the clinical features, diagnosis, treatment, and prognosis of retroperitoneal schwannomas.

METHODS: A total of 113 patients with retroperitoneal neoplasms treated at the Department of General Surgery of the First Hospital of China Medical University in the past decade, of whom 20 were diagnosed with retroperitoneal schwannoma. The clinical data for the 20 patients were retrospectively reviewed.

RESULTS: All the patients underwent radiological examination and surgical excision, and were confirmed with retroperitoneal schwannoma by pathology. Except that two cases undergoing enucleation and partial excision were lost to follow-up, all others (18/20) were evaluable. Among the 18 cases, 17 were treated by complete surgical resection, had high quality lives, and showed no evidence of recurrence during a mean follow-up of 40.5 mo (range 11 to 83 mo), and 1 underwent enucleation and had the same favorable prognosis during the 28-month follow-up.

CONCLUSION: Retroperitoneal schwannomas are rare and preoperative diagnosis is difficult. Radiologic findings cannot make an accurate diagnosis. Complete surgical excision should be considered. Patients undergoing complete surgical resection tend to do well without evidence of recurrence.

Imaging of the retroperitoneum

The retroperitoneum is the compartmentalized space bounded anteriorly by the posterior parietal peritoneum and posteriorly by the transversalis fascia. It extends from the diaphragm superiorly to the pelvic brim inferiorly. This article discusses clinically relevant anatomy of the abdominal retroperitoneal spaces, their cross-sectional imaging evaluation with computed tomography and magnetic resonance imaging, and the imaging features of common retroperitoneal pathologic processes.

Cystic retroperitoneal renal hilar ancient schwannoma: Report of a rare case with atypical presentation masquerading as simple cyst

Schwannoma is a benign soft tissue tumor of neural origin arising from the Schwann cells of the neural sheath. It has rarely been reported in renal or perirenal region. The preoperative diagnosis has mostly been confused with renal cell carcinoma in this location in most previous reports. We report a case that presented with a large "simple cystic" mass at the renal hilum. The preoperative differential diagnosis included hilar renal cortical cyst, renal sinus cyst, ureteropelvic junction obstruction (UPJO), or even a hydatid cyst. The final diagnosis was clinched only on histopathological examination.

Three cases of retroperitoneal schwannoma diagnosed by EUS-FNA

Schwannomas are peripheral nerve tumors that are typically solitary and benign. Their diagnosis is largely based on surgically resected specimens. Recently, a number of case reports have indicated that retroperitoneal schwannomas could be diagnosed with endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). We report the diagnosis of three cases of schwannoma using EUS-FNA. Subjects were two males and one female, ages 22, 40, and 46 years, respectively, all of whom were symptom-free. Imaging findings showed well-circumscribed round tumors. However, as the tumors could not be diagnosed using these findings alone, EUS-FNA was performed. Hematoxylin-eosin staining of the resulting tissue fragments revealed bland spindle cells with nuclear palisading. There was no disparity in nuclear sizes. Immunostaining revealed S-100 protein positivity and all cases were diagnosed as schwannomas. Ki-67 indexes were 3%-15%, 2%-3%, and 3%, respectively. No case showed any signs of malignancy. As most schwannomas are benign tumors and seldom become malignant, we observed these patients without therapy. All tumors demonstrated no enlargement and no change in characteristics. Schwannomas are almost always benign and can be observed following diagnosis by EUS-FNA.

Atypical presentations of retroperitoneal giant schwannomas

Schwannomas are usually benign rare tumors that originating from Schwann cells of peripheral nerve sheaths. Presentation is generally varied and changed in a non-specific range from abdominal mass, flank pain to incidental findings. Herein we report 2 cases of retroperitoneal giant schwannomas with different clinical presentations, of whom one presented with vague abdominal pain, palpable abdominal mass for 4 years, swelling and bilateral hydronephrosis that caused by giant abdominal mass; the other one presented with right flank pain, rectal hemorrhage and lower extremities edema. Two patients were treated by complete surgical excision of masses. The histological and immunohistochemical diagnosis was reported as benign schwannoma. Both of patients are doing well and had no recurrence in 9 years and 28 months follow-up, respectively.

Experience with adrenal schwannoma in a Chinese population of six patients

OBJECTIVES

Benign adrenal schwannoma is an extremely uncommon cause of incidentaloma. This article describes our experience with the diagnosis and treatment of adrenal schwannoma in a Chinese population of 6 patients. To our knowledge, this is the largest series of this uncommon adrenal tumor treated in a single center.

METHODS

From May 1999 to May 2009, 6 patients with incidentally discovered adrenal schwannoma were operated on at a tertiary referral hospital in Eastern China. Clinical details, radiographic features, laboratory examinations, pathological findings, and follow-up data of these patients were analyzed.

RESULTS

Of the 6 patients, 4 were females (F) and 2 were males (M), with a mean age of 40.5 yr (range: 30-47, M:F=2:1). The 6 patients were managed with open unilateral adrenalectomy; 5 patients had schwannomas on the left side, and 1 on right side. Abnormal urine catecholamine was detected in 1 patient. The mean pathological size of these tumors was 4.3 ± 1.1 cm. The diagnosis of schwannoma was based on classic histological findings, and supported by immunohistochemistry of S-100, vimentin, and ABC positivity. In the follow- up of 47.5 ± 32.3 months, no recurrence and metastasis were observed.

CONCLUSIONS

Although there may be some clues for radiological diagnosis of adrenal schwannoma, preoperative misdiagnosis is not infrequent. Those tumors may occasionally have endocrine function. Histological examination is the key of diagnosis, and surgical resection is the treatment of choice once malignancy cannot be excluded by preoperative analyses.

Recurrent retroperitoneal Schwannomas displaying different differentiation from primary tumor: case report and literature review

Background

Retroperitoneal Schwannomas are uncommonly found in the retroperitoneum and few of them show malignant transformation and invasion. Local recurrence are common in malignant Schwannomas with very few reports of tumor distinct differentiation at recurrences.

Case presentation

We report here a rare case of retroperitoneal schwannoma with multiple origins from retroperitoneum and pelvic wall. Pathological examination confirmed the case as a schwannoma with malignant transformation. Radical dissection of the tumors along with the sacrifice of adjacent sigmoid colon and left kidney failed to provide a cure for this patient. Due to tumor recurrence, a second and a third surgery of radical excision were performed 6 months and 17 months later after the first surgery, respectively. Histopathologic analysis identified that the recurrent tumors were different from the original schwannoma because of their smooth muscle-like differentiation.

Conclusion

Malignant schwannomas are uncommon sarcomas with a high incidence of local recurrence. Distinct immunohistochemical staining results of the tumors at recurrence indicate their potential of smooth-muscle like differentiation. Radical excision of the tumors may provide benefit for their local recurrences.

Schwannoma in the retroperitoneum

Schwannoma (neurilemmoma) is a peripheral nerve sheath tumor and commonly occurs singularly on the head, neck, and trunk. Giant schwannoma is rarely located on the retroperitoneum and pelvic cavity. The majority of symptoms caused by the tumor are due to the effect of its mass. Surgical resection is enough to treat the tumor. Schwannoma is reported usually as benign, and despite incomplete resection of the tumor, the risk of recurrence and metastasis is low. A schwannoma on the retroperitoneum that was preoperatively misdiagnosed as a malignant adnexal mass in a 60-year-old menopausal woman is presented, with a brief review of the literature.

Retroperitoneal ancient schwannoma presenting as an adrenal incidentaloma: CT and MR findings

A 35-year-old woman was referred to our institution for additional examinations to evaluate bilateral suprarenal masses incidentally found on abdominal ultrasonographic images obtained during an annual medical health checkup. Our computed tomographic scans showed bilateral and well-circumscribed low-density suprarenal masses, while MRI revealed the tumors to be heterogeneous with low intensity on T1-weighted images and high intensity on T2-weighted images. A laparoscopic adrenalectomy was performed under the suspicion of a malignant tumor, such as a malignant fibrous histiocytoma. Pathologic findings indicated a retroperitoneal ancient schwannoma of two histologic types: Antoni A and Antoni B. We considered that elucidation of the characteristic features of a schwannoma would provide helpful preoperative information for diagnosis.

Proton magnetic resonance spectroscopy findings of a sacrococcygeal schwannoma

Schwannoma is tumor of peripheral nerves, originating from Schwann cells. It is a rare nerve sheath tumor, which frequently occurs in the intracranial acoustic nerve and spinal nerves. We report on a 28-year-old woman who suffered from a large pelvic mass that was diagnosed to be sacrococcygeal schwannoma. The features of proton magnetic resonance spectroscopy (MRS) study are discussed. The magnetic resonance imaging instrument was a 1.5 T, Gyroscan Intera with a body coil as a radiofrequency transmitter and a signal receiver. T2-weighted images were obtained under the following conditions-turbo spin echo (TSE) T2: turbo spin echo repeat time (TR) = 4500 msec, echo time (TE) = 96 msec. Single voxel MRS was performed by the point-resolved spectroscopy technique with a long TE (136 msec). MRS measurement was performed on two different parts of the tumor. As well as strongly elevated choline and lipid signals, the tumor spectrum showed increased N-acetylaspartate resonances. MRS can be used effectively in the preoperative diagnosis of retroperitoneal and pelvic masses, which demonstrate unusual clinical features.

Retroperitoneal schwannoma

BACKGROUND

Retroperitoneal schwannomas are rare, benign tumors. The aim of this study is to present our surgical experience with 7 such tumors.

METHODS

Between 1989 and 2004, 7 patients with pathologically proven retroperitoneal schwannomas were reviewed retrospectively.

RESULTS

There were 6 male patients and 1 female patient, with a mean age of 43 years (range, 23 to 58 years). Two patients were symptomatic and presented with abdominal discomfort, and none of the patients suffered from von Recklinghausen's disease. All the patients underwent computed tomography scanning, which showed a heterogenous retroperitoneal mass, 4 of which were thought to arise from the adrenals. In 2 patients, calcification was seen in the tumors. All 7 of the patients had a preoperative diagnosis of a retroperitoneal tumor including 3 patients who were thought to have adrenal neoplasms (1 patient had a diagnosis of an adrenal neoplasm excluded on magnetic resonance imaging). Laparotomy and complete excision of tumors were performed in all the patients, and there was no morbidity or mortality. The schwannomas had a mean maximum diameter of 7.3 cm (range, 4 to 14 cm), and they were all benign. At a mean follow-up of 17 months (range, 3 to 48 months) postresection, all the patients remained free from recurrence.

CONCLUSION

Retroperitoneal schwannomas are rare tumors that are difficult to diagnose preoperatively. Radiologic findings are usually nondiagnostic. The treatment of choice is complete surgical excision.

Imaging features of retroperitoneal and pelvic schwannomas

AIM

To describe the imaging features of retroperitoneal and pelvic schwannomas.

MATERIALS AND METHODS

The presenting cross-sectional imaging for 18 sequential patients with retroperitoneal or pelvic schwannomas was reviewed retrospectively. Note was made of tumour diameter, position, homogeneity, margin, shape, calcification and invasion into adjacent structures. Where MRI had been performed, T1 and T2 signal intensity relative to skeletal muscle, and the degree and pattern of enhancement with gadolinium, were also assessed.

RESULTS

Imaging from 13 patients was available for review. The mean tumour diameter was 8.7 cm (range 4 to 15 cm); 9 schwannomas were located in the pelvis and 4 in the retroperitoneum; 12 cases showed smooth, regular margins and 1 case irregular, invasive margins. The tumours were homogeneous in 5 cases and heterogeneous with cystic change in 8; in 2 cases there was smooth expansion of a sacral nerve root exit foramen, and in 1 there was bony destruction of the sacrum and extension of tumour into the spinal canal. In 5 cases MRI was performed; on T1-weighted images all tumours were isointense; on T2-weighted images 4 tumours were hyperintense and 1 was isointense to skeletal muscle. In all cases the diagnosis was confirmed by core biopsy.

CONCLUSION

Retroperitoneal and pelvic schwannomas typically form large, well-circumscribed masses in the retroperitoneum or presacral area, and frequently undergo cystic degeneration. They can occasionally cause bony changes in the spine, but otherwise do not invade or obstruct adjacent structures. Although they are rare, it is important for the radiologist to recognize the typical appearance of schwannomas because they can be mistaken for malignant tumours.

[Benign retroperitoneal schwannoma. Incidental diagnostic in patient with hematuria of the percusionist]

The incidence of retroperitoneal primitive tumour varies from the 0.3 to 3%. The sarcomas suppose the group but it frequents of retroperitoneal tumour, being the Schwannoma an unusual tumour with an incidence from 1% to 50% of the retroperitoneal primary tumours. The schwannoma also denominated neurinoma or neurolenoma, it is a derived tumour of the cells of Schwann of the outlying nerves. It is characterized by their clinical and radiological inespecify, being the diagnose pathological, with intense positive inmunohistoquimics to the protein S-100. The election treatment is the surgical remove, with wide margins; not being described cases of malignización neither of metastasis at distance, but if the recurrence existence at probably secondary local level to incomplete resection.

[Renal neurilemoma--a rare differential diagnosis of renal tumors]

Neurilemomas originate from the Schwann cells of nerve sheaths. They can occur ubiquitously as benign or malign variants. Renal neurilemomas are extremely rare. Imaging does not allow a certain diagnosis. Complete tumor resectioning is the only curative therapy. Effective conservative treatment is not known. Histological criteria of renal neurilemoma are: mesenchymal, spindle cell, capsulated tumor intensely positive to S-100 antiserum. Epithelial markers do not react.

Retroperitoneal schwannoma bearing at the right vaginal wall

Benign schwannoma commonly arises from schwann cells of the neural sheath. We report a rare case of retroperitoneal schwannoma bearing at the vaginal wall. The tumor was a 7x5x4-cm solid mass revealed using several image techniques and diagnosed to be a retroperitoneal tumor preoperatively. The tumor was tightly attached to the vaginal submucosal tissue, so complete surgical resection was difficult. However, an almost complete resection was carried out macroscopically using laparotomy. Histologic and immunohistochemical studies confirmed the diagnosis. The patient has been followed for 18 months after the operation, but there is no evidence of recurrent tumor.

Large pelvic schwannoma causing bilateral hydronephrosis

Schwannoma is a tumor originating from neural sheath schwann cells. We report here a case of benign retroperitoneal schwannoma that caused bilateral ureterohydronephrosis. The retroperitoneal localization in the present case is unusual. The tumor was 21 x 18 x 11 cm in dimension and reached from the prostate to the umbilical level. Even though the patient had bilateral hydronephrosis, the renal function tests results were in the normal range. Complete surgical excision was achieved by anterior laparotomy. Histological and immunohistochemical studies confirmed the diagnosis. At 6 months follow-up there was no evidence of recurrence and renal function test results were normal.

Résection d’un schwannome rétropéritonéal en sablier par abord combiné

BACKGROUND AND PURPOSE

We report a remarkable case of retroperitoneal schwannoma with significant spinal growth illustrating the effectiveness of a combined surgical approach.

METHODS

A 41-year-old man presented with a long history of back pain and unexplained weight loss. An abdominal mass was found in the right upper quadrant. The CT-scan revealed a partially cystic lesion located in the right psoas muscle. Spinal extension was noticed through the L1-L2 neural foramen. MRI better showed the wide rostro-caudal extension in the spinal canal.

RESULTS

Bilateral L1 and L2 laminectomy was performed to remove the spinal portion of the tumor. It was extradural but attached to the dura. The roots were not infiltrated. The retroperitoneal mass was removed by an anterior transperitoneal approach. The histological examination did not reveal criteria of malignancy.

CONCLUSIONS

Retroperitoneal schwannomas are rare and their preoperative diagnosis remains difficult. In case of significant spinal growth, a combined surgical exposure should be preferred to allow total removal of the lesion and control of the neurological structures.

Benign retroperitoneal schwannoma: a case series and review of the literature

OBJECTIVES

To present our experience with four retroperitoneal schwannomas treated by surgical excision and review the current literature. Retroperitoneal schwannomas are rare, benign tumors and infrequently present to the urologist.

METHODS

From 1997 through 2002, the charts of 164 patients with a diagnosis of benign retroperitoneal soft tissue mass were reviewed. Of those, four had a pathologic diagnosis of retroperitoneal schwannoma.

RESULTS

Three of the 4 patients were women, with a median age of 54 years (range 46 to 80). The average tumor size was 13.7 cm (range 8.8 to 20). All patients underwent magnetic resonance imaging, computed tomography, or ultrasonography, and 3 of the 4 patients underwent a computed tomography-guided fine needle aspiration biopsy (all were either inaccurate or inconclusive). All patients underwent complete tumor excision with free margins of resection and tolerated surgery without any complications. None of the patients have had any evidence of recurrence at a mean follow-up of 26 months (range 10 to 48).

CONCLUSIONS

Retroperitoneal schwannomas are difficult to diagnose preoperatively. Computed tomography-guided fine needle aspiration biopsy does not appear to provide an accurate preoperative diagnosis. The surgical approach should focus on complete excision of the mass. Patients undergoing complete surgical resection tend to do well without evidence of early recurrence.

Presacral cystic schwannoma in a man

Presacral cystic schwannomas are rare, difficult to diagnose, and have only been reported in women. We present the first such case in a male patient. It was incidentally diagnosed during an evaluation for renal colic in a 52-year-old man. The presacral lesion was cystic on computed tomography and measured 10 cm in diameter. The appearance on pelvic magnetic resonance imaging was hyperintense on T(2)-weighted images and of low to intermediate intensity on T(1)-weighted images. Complete excision was achieved without bladder injury. The patient voided without difficulty and was free of local recurrence at 12 months after surgery.