Benign retroperitoneal neural sheath tumors in patients without von Recklinghausen's disease

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.

Retroperitoneal solitary neurofibroma mimicking lymph node metastasis of colon cancer: a case report

BACKGROUND

A neurofibroma is a benign tumor that arises from Schwann cells and neurofibromas occur throughout the skin of neurofibromatosis type 1 (NF-1: Von Recklinghausen's disease) patients. A retroperitoneal solitary neurofibroma without any clinical signs of NF1 has been rarely reported. Herein, we present a case of a retroperitoneal solitary neurofibroma mimicking lymph node metastasis of colon cancer as well as a literature review.

CASE PRESENTATION

An 80-year-old woman with abdominal pain and nausea was transported and diagnosed with bowel obstruction arising from sigmoid colon cancer A colonic stent was inserted to alleviate the bowel obstruction. A computed tomography scan with contrast revealed a liver tumor in segment 3, and an enlarged lymph node around the abdominal aorta. Whole-body 18F-fluorodeoxyglucose-positron emission tomography-CT (FDG-PET-CT) examine revealed increased FDG uptake in the liver tumor and enlarged lymph node. Liver and distant lymph node metastasis were diagnosed and we made a plan for a two-stage operation of the colon cancer and the metastatic lesions because laparotomy resection was needed for the retroperitoneal lymph node. Laparoscopic sigmoid colectomy was performed first. Pathological examination showed a tubular adenocarcinoma. A laparotomy for the metastatic lesions was performed to ensure complete lymph node dissection secondly. Histopathological findings of the liver tumor showed metastasis of sigmoid colon cancer. However, the tissue regarded as the enlarged lymph node was diagnosed as a neurofibroma. No metastasis and recurrence were observed.

CONCLUSION

Although most neurofibromas are benign, malignant transformation of a neurofibroma is possible. PET-CT showed our patient had a high accumulated retroperitoneal tumor co-existing with colon cancer and liver metastasis. The treatment strategy of a solitary neurofibroma must be selected carefully considering the site of occurrence and the patient's background and aggressive resection of a tumor co-existing with another malignant tumor is needed.

Solitary Retroperitoneal Neurofibroma Associated With Deep Vein Thrombosis in a 40-Year-Old Male

A neurofibroma is a benign, non-encapsulated neoplasm of the peripheral nerve sheath. These tumors are a notorious manifestation of the autosomal dominant condition known as neurofibromatosis type 1, where they present as multiple, cutaneous masses with high malignant potential. On the contrary, benign solitary retroperitoneal neurofibromas (SRN) occur without any associated conditions and have rarely been documented. Our case is of a 40-year-old male who presented with a three-month history of painful calf swelling, refractory to over-the-counter painkillers which was later diagnosed as deep vein thrombosis (DVT). A computed tomography (CT) angiogram was done which revealed a mass in the retroperitoneum impinging on the inferior vena cava (IVC). Approximately one month later, the whole mass was surgically excised and histopathology confirmed the diagnosis of a neurofibroma. This case presentation proved to be novel as it highlights the evaluation and management of a rare SRN which resulted in extensive DVT.

Lumbosacral plexiform neurofibroma: a rare case in an adult without neurofibromatosis type I

Plexiform neurofibromas are an uncommon variant of neurofibromas that are described as being essentially pathognomonic of neurofibromatosis type 1 (NF1). Plexiform neurofibromas in the absence of NF1 are extremely rare. We present the case of a 38-year-old woman with a large multilobulated lumbosacral mass extending into the pelvis and proximal thigh. Histopathology of a CT-guided biopsy of the mass revealed it to be a neurofibroma. The imaging findings were consistent with a plexiform subtype. Further imaging and clinical workup showed that the patient had no other identifiable neurofibromas and did not meet criteria for the diagnosis of NF1.

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.

[Primitive benign retrovesical schwannoma: an extremely rare tumor, a case report]

Schwannoma is usually a benign tumor of nervous origin arising from Schwann sheath cells. It is an extremely rare tumour because of its low incidence and its retrovescical localization. Histological and immunohistochemical examinations confirm the histological type as well as the benign or malignant origin of schwannoma. Because of the risk of recurrence and malignant transformation, excision must be complete. We report the case of a 39 years old patient, hospitalized for chronic pelvic pain accompanied by a sensation of heaviness, lower urinary tract irritation and urinary hesitancy. Diagnostic imaging (ultrasound, CT scan, MRI) of the pelvis showed a left-lateralized retrovescical mass with a thin wall, measuring 68x70x70 mm exerting mass effect on the bladder and the sigmoid. The surgical procedure, a midline laparotomy, allowed the removal of a well encapsulated retrovesical mass. Histological and immunohistochemical examinations concluded to a benign schwannoma. Recidivism and malignant transformation, although rare after surgery, impose postoperative clinical monitoring and annual CT scanning.

Sacrococcygeal neurofibroma: rare cause for chronic pelvic pain

Pelvic pain is a common gynecologic complaint. Retroperitoneal pelvic tumors are rarely a cause of pelvic pain. Neurofibroma is an uncommon pelvic retroperitoneal tumor, and only 17 cases are reported to date. A 38-year-old woman with chronic pelvic pain had a soft fixed mass that was the size of an orange in the right posterolateral fornix, with a normal uterus on pelvic examination, and a mass of 6.3 × 5.2 cm with mixed echotexture on the right side separate from both ovaries on transvaginal ultrasonography. A provisional diagnosis of retroperitoneal mass probably a retroperitoneal teratoma was made. Laparoscopy was performed; an ill-defined retroperitoneal soft tissue mass of about 6 cm was seen on the right pararectal and presacral area, displacing the rectum toward the left side. The mass was soft and jellylike without a cyst wall. Histopathologic study and immunohistochemistry results were consistent with neurofibroma of the sacrococcygeal regions. To our knowledge this is the third case of sacrococcygeal neurofibroma treated by complete laparoscopic excision. Gynecologists should keep sacrococcygeal neurofibroma as a differential diagnosis of pelvic pain with atypical location of a pelvic mass. A high index of suspicion and an appropriate imaging technique are needed for accurate diagnosis. Laparoscopy seems to be a safe and effective method of managing retroperitoneal presacral neurofibromas.

Giant Posterior Mediastinal Ancient Schwannoma Requiring Thoracoabdominal Resection: A Case Report and Literature Review

Posterior mediastinal schwannomas are benign, slow growing nerve sheath tumors and rarely cause symptoms. We present a case of a 47-year-old man who presents with severe mid-back pain and dyspnea on exertion. Chest radiograph and computed topography revealed a large posterior mediastinum mass. Surgical resection required en bloc resection of a portion of the diaphragm, and wedge resection of the left lower lobe of the lung via left thoracoabdominal approach. Pathology was consistent with ancient schwannoma. This case is unique due to the location and size of the mass and the surgical approach required for complete resection.

[Presacral schwannoma with degenerated areas ("ancient schwannoma")]

A presacral, degenerative schwannoma ("ancient schwannoma") is a rare entity. The clinical signs are nonspecific, and a reliable preoperative diagnosis is difficult. Tumor heterogeneity with calcifications may be seen in degenerated schwannomas on MRI or CT but not necessarily. First-line treatment is complete surgical excision. We present the case of a 44-year-old male who required surgery for a presacral mass. Histopathological examination revealed the diagnosis of a schwannoma with degenerated areas.

Huge pelvi-abdominal malignant inflammatory myofibroblastic tumor with rapid recurrence in a 14-year-old boy

Inflammatory myofibroblastic tumor (IMT) is an uncommon benign neoplasm with locally aggressive behavior but malignant change is rare. We report an unusual case of pelvic-abdominal inflammatory myofibroblastic tumor with malignant transformation in a 14-year-old boy presenting with abdominal pain and 9 kg body weight loss in one month. Computed tomography revealed a huge pelvi-abdominal mass (30 cm), possibly originating from the pelvic extraperitoneal space, protruding into the abdomen leading to upward displacement of the bowel loops, downward displacement of the urinary bladder, massive central necrosis, a well-enhanced peripheral solid component with prominent peritumoral vascularity. Subsequent examination confirmed the computed tomographic findings. Histopathologic examination revealed proliferative epitheloid and spindle cells, inflammatory cell infiltration and high mitotic counts. Immunohistochemistry was strongly positive for anaplastic lymphoma kinase and revealed a high proliferative index (ki-67 = 40%). DNA sequencing and electronic microscopy further confirmed the primitive fibroblastic cell phenotype of the tumor and a final diagnosis of inflammatory myofibroblastic tumor with malignant transformation was established. Rapid tumor recurrence was noted 20 d after radical tumor resection. To our knowledge, this is the largest documented case of IMT in a pediatric patient and the first report of IMT with malignant transformation originating from the pelvic extraperitoneal space.

Special problems encountering surgical management of large retroperitoneal schwannomas

Background

Retroperitoneal schwannomas are rare, usually benign tumors that originate in the neural sheath and account for only a small percentage of retroperitoneal tumors. The aim of this clinical study is to present our experience in managing retroperitoneal schwannomas with a review of the current literature and to point out the surgical technical difficulties we faced, due to the tumor's strange behavior that eroded the vertebra in two cases without causing malignant invasion.

Methods

We reviewed the medical files of 69 patients treated in our department for retroperitoneal tumors from January 1991 until December 2006. Five patients had retroperitoneal schwannomas according to pathology report.

Results

There were two male and three female patients, with a mean age of 56 years (range 44–67 years). All patients were asymptomatic and none suffered from von Recklinghausen disease. Imaging workup included ultrasonography, computed tomography and magnetic resonance imaging. One patient, after having a non-diagnostic computed tomography fine needle aspiration (CT-FNA), underwent exploratory laparotomy and incisional biopsy that established the diagnosis of schwannoma. After complete excision of the tumors, postoperative course was uneventful in all patients. Tumors' maximum diameter was 12.7 cm (range 7–20 cm). No recurrences were detected during the follow up period (6–75 months).

Conclusion

Preoperative establishment of diagnosis is difficult in case of retroperitoneal schwannomas, however close relationship of retroperitoneal tumors with adjacent neural structures in imaging studies should raise a suspicion. Complete surgical resection is the treatment of choice. Histology and Immunohistochemistry confirms the diagnosis.

Nerve sheath tumors involving the sacrum. Case report and classification scheme

Nerve sheath tumors that involve the sacrum are rare. Delayed presentation is common because of their slow-growing nature, the permissive surrounding anatomical environment, and nonspecific symptoms. Consequently, these tumors are usually of considerable size at the time of diagnosis. The authors discuss a case of a sacral nerve sheath tumor. They also propose a classification scheme for these tumors based on their location with respect to the sacrum into three types (Types I-III). Type I tumors are confined to the sacrum; Type II originate within the sacrum but then locally metastasize through the anterior and posterior sacral walls into the presacral and subcutaneous spaces, respectively; and Type III are located primarily in the presacral/retroperitoneal area. The overwhelming majority of sacral nerve sheath tumors are schwannomas. Neurofibromas and malignant nerve sheath tumors are exceedingly rare. Regardless of their histological features, the goal of treatment is complete excision. Adjuvant radiotherapy may be used in patients in whom resection was subtotal. Approaches to the sacrum can generally be classified as anterior or posterior. Type I tumors may be resected via a posterior approach alone, Type III may require an anterior approach, and Type II tumors usually require combined anterior-posterior surgery.

Retroperitoneal giant schwannomas: report on two cases and review of the literature

The occurrence of massive retroperitoneal schwannomas is extremely rare and their presence may only be expressed by insidious onset of non-specific and misleading symptoms with a predominance of lower back pain. MRI scan as the imaging procedure of choice will demonstrate the tumour location and its relation to the surrounding structures, but due to heterogeneity and degeneration in some tumours, it may mimic malignancy. Hence tissue sampling through needle biopsies are essential to verify the diagnosis prior to surgery. Tumour excision in toto is considered the treatment of choice, but it can be hazardous especially if the tumour is adherent to the presacral venous plexus. Severe bleeding complications due to the damage of venous structures have to be encountered, and establishing lasting haemostasis may pose considerable difficulties. Hence surgery should be attempted with full precautions, and preoperative counseling of the patient. If malignancy can safely be excluded, laparoscopic piecemeal excision should be considered as an alternative treatment as recurrence is unlikely. Definition of the originating nerve might not always be possible and a minor degree of neurological impairment has therefore to be anticipated.

Presacral solitary giant neurofibroma without neurofibromatosis type 1 presenting as pelvic mass--case report

A 35-year-old woman presented with a solitary neurofibroma in an unusual presacral location without neurofibromatosis manifesting as bilateral chronic sciatica for 2 years. She was initially considered as having a giant right ovarian mass, but was referred with a prediagnosis of solitary giant sacral nerve sheath tumor. The initial differential diagnosis was based on neuroimaging. A right-sided J incision with the extraperitoneal approach provided good exposure and handling of the tumor bed. Almost total excision without neurological deficit was possible. The histological diagnosis was neurofibroma. Benign retroperitoneal neural sheath tumors in patients without von Recklinghausen's disease are quite rare. Intrapelvic tumors are often diagnosed at a later stage. Neuroimaging is very helpful to delineate this unusual site and the extent of tumor development, and to determine the appropriate surgical intervention. A clear understanding of retroperitoneal anatomy is essential for safe removal of such tumors. Complete resection is preferred to prevent local recurrence and malignant transformation. Although root section is inevitable, neurological deficit is unlikely.

[Retroperitoneal schwannoma. Case report]

Retroperitoneal schwannoma is a rare tumor originating in the neural sheath. We report the case of a 48 year-old women. She had a ten year history of lumbal pain. The abdominal sonography had revealed a left retroperitoneal tumor that compresses the left renal cavities. The abdominal CT scan visualized a 56 mm, homogenous, well demarcated, retroperitoneal mass with a low attenuation. This mass with multiple enhanced septa is separated from the left adrenal gland. The diagnosis of a cystic lymphangioma is made. We perform surgical exeresis of the tumor by a left lumbal laparotomy. The pathology examination concludes in an altered schwannoma with Antoni B patterns. Retroperitoneal schwannoma is a primary neural benign tumor with a good prognosis. The management is surgical.