Robot-assisted laparoscopic resection of a huge pelvic tumor: A case report.

The traditional open surgery, for the treatment of huge tumor in the narrow space of pelvic cavity and in close proximity to pelvic organs and neurovascular structures, is very difficult and challenging. We report a case of huge neurilemmoma operated using the robot-assisted laparoscopy. We used interventional pre-operation embolization to control blood supply of tumor because MRI showed the tumor had a sufficient blood supply.

[Complete resection of a posterior mediastinal tumor after preoperative identification of artery of Adamkiewicz].

The thoracolumbar spinal cord receives its blood supply primarily from the artery of Adamkiewicz (AA), a branch of thoracolumbar intercostal arteries. Aortic cross-clamping during operation for descending aortic aneurysms can cause paraplegia due to spinal cord ischemia secondary to low blood flow through the AA. A 69-year-old woman was diagnosed with a left posterior mediastinal tumor measuring 66 mm. The tumor was adjacent to the thoracic aorta between Th10 to Th12 vertebral levels. Preoperative 3-dimensional computed tomography (3D-CT) imaging revealed 2 AAs originated from the 10th and 11th left intercostal arteries just near the tumor. The patient underwent a left thoracotomy and the 2 intercostal arteries were carefully dissected from the encapsulated tumor. Complete resection was safely achieved with preservation of the AAs. Pathology revealed a schwannoma. There were no complications. In performing thoracic surgery for posterior mediastinal tumors, it is important to identify the AAs preoperatively and preserve them.

Effects of pigment epithelium derived factor (PEDF) on malignant peripheral nerve sheath tumours (MPNSTs).

Neurofibromatosis type 1 (NF1) is an inherited genetic disease affecting 1 in 3,500 individuals. A prominent feature of NF1 is the formation of benign tumours of the peripheral nerve sheath (neurofibromas). However, these can become malignant and form highly metastatic malignant peripheral nerve sheath tumours (MPNST), which are usually fatal despite aggressive surgery, chemotherapy, and radiotherapy. Recent studies have shown that pigment epithelium-derived factor (PEDF) can induce differentiation and inhibit angiogenesis in several kinds of tumours. The present study was designed to determine the in vitro and in vivo effects of PEDF on MPNST angiogenesis and tumour growth. PEDF inhibited proliferation and augmented apoptosis in S462 MPNST cells after 48 h of treatment in culture. In xenografts of S462 MPNST cells in athymic nude mice, PEDF suppressed MPNST tumour burden, due mainly to inhibition of angiogenesis. These results demonstrate for the first time inhibitory effects of PEDF on the growth of human MPNST via induction of anti-angiogenesis and apoptosis. Our results suggest that PEDF could be a novel approach for future therapeutic purposes against MPNST.

Study of neurinomas with ultrasound contrast media: review of a case series to identify characteristic imaging patterns.

PURPOSE: The aim of this study was to evaluate whether there exists a characteristic distribution pattern of vessels within neurinomas that may be used to characterise this type of lesion by employing a contrast-specific ultrasound technique. MATERIALS AND METHODS: Between January 2003 and May 2010, 66 suspected neurinomas were evaluated according to their sonographic features (solid fusiform mass with well-defined margins located in direct continuity with the nerve that was not always discernible and heterogeneous as a result of the presence of small cystic areas or calcifications). The lesions were examined using a sonographic contrast medium consisting of sulphur hexafluoride microbubbles and equipment with dedicated contrast-specific software [contrast tuned imaging (CnTI)]. Of these lesions, five were excluded from the analysis because the definitive diagnosis was not available (in two cases, the follow-up was still in progress, whereas in the remaining three, there was no follow-up). Our study, therefore, is based on 61 surgically excised lesions that were confirmed to be neurinomas by histology, which is regarded as the gold standard. RESULTS: In 41/61 cases (67.2%), we identified an enhancement pattern that we termed reticular owing to the interweaving of blood vessels, of which two subtypes were identified depending on whether the interwoven vessels were densely or sparsely packed: loose-knit reticular in 18/41, and tight-knit reticular in 23/41. In 20/61 (32.8%) cases, we observed a vascular pattern of diffuse heterogeneous enhancement, which was divided into two subtypes based on the presence of one (7/20) or more (13/20) avascular areas. CONCLUSIONS: Results showed that all neurinomas studied could be divided into two groups according to the type of enhancement pattern observed: reticular or diffuse heterogeneous.

[A case of giant presacral neurilemoma resected without blood transfusion after embolization of tumor vessels].

A 71-year-old man began feeling a lower abdominal pain at bowel movement about one year ago. He was found to have a pelvic tumor during a health examination and referred to our hospital for further evaluation. CT and MRI scans demonstrated a giant pelvic tumor, 10 cm in size, which compressed the rectum. The likely preoperative diagnosis was leiomyosarcoma from the rectum or neurilemoma. To regulate intraoperative hemorrhaging and to reduce the tumor size, angiography was performed at two days before the operation and embolization of the tumor vessels was done. He had a tumor resection and a low anterior resection of the rectum and a transient colostomy of the ascending colon without blood transfusion. The resected tumor was covered with thin yellowish-white capsule with smooth surface, elastic hard on palpation, and was measured 10.5 × 9 × 10.5 cm, and weighted 320 g. The pathological diagnosis was neurilemoma (schwannoma) consisting both Antoni type A and Antoni type B sections.

Quantitative Analysis of Superb Microvascular Imaging versus Color-Coded Doppler Sonography for Preoperative Evaluation of Vascularization of Schwannomas.

PURPOSE: Comparison of vascularization of schwannomas, benign peripheral nerve sheath tumors, using color-coded Doppler sonography (CCDS) and the Toshiba monochrome Superb Microvascular Imaging (mSMI) (Minato, Tokyo, Japan) technique. METHODS: In a retrospective single-center analysis, 16 patients were identified with histologically confirmed schwannomas. Between March and June 2018, all of them underwent ultrasonography using mSMI and CCDS before surgery. Schwannoma vascularization was quantitatively measured using ImageJ, an open platform for scientific image analysis. As the diagnostic gold standard, magnetic resonance imaging was mandatory. RESULTS: The mSMI and CCDS vascularization showed a moderate agreement between the techniques (κ = 0.5556; p = 0.0066). The quantitative visual assessment of the vascularization revealed no difference (25.3 ± 8.2 vs. 18.2 ± 3.8; p = 0.0532). Significant differences were found for the quantitative assessment of CCDS with ImageJ (26.8 ± 8.8 vs. 19.3 ± 2.8; p = 0.0368). However, in a subanalysis of highly vascularized schwannomas, mSMI revealed significant differences to slightly vascularized schwannomas (32.0 ± 8.2 vs. 21.3 ± 6.1; p = 0.0065) but not between moderately and slightly vascularized types (p = not significant). CONCLUSION: The mSMI mode is qualitatively superior to conventional CCDS; however, quantitative analysis of the vascularization of schwannomas revealed no significant quantitative advantage for mSMI. Nevertheless, the mean ImageJ values showed a positive trend toward a better representation of the vascularization degree of schwannomas with mSMI.

Multiple intradural extramedullary tumours presenting with paraplegia after trauma.

Intraspinal nerve-sheath tumours are generally slow growing and are diagnosed after causing symptoms such as back pain and progressive neurological symptoms. We present a rare example of multiple schwannomas located in the thoracolumbar spine in a previously asymptomatic patient who developed severe neurological deficits after a motor-vehicle accident. The exact mechanism of neurological compromise in this patient remains unclear. Circulatory instability in the early post-traumatic course could have contributed to pathogenesis.

Cervical sympathetic chain schwannoma masquerading as a carotid body tumour with a postoperative complication of first-bite syndrome.

Carotid body tumours (CBT) are the most common tumours at the carotid bifurcation. Widening of the bifurcation is usually demonstrated on conventional angiography. This sign may also be produced by a schwannoma of the cervical sympathetic plexus. A 45-year-old patient presented with a neck mass. Investigations included contrast-enhanced CT, MRI and magnetic resonance arteriography with contrast enhancement. Radiologically, the mass was considered to be a CBT due to vascular enhancement and splaying of the internal and external carotid arteries. Intraoperatively, it was determined to be a cervical sympathetic chain schwannoma (CSCS). The patient had a postoperative complication of first-bite syndrome (FBS).Although rare, CSCS should be considered in the differential diagnosis for tumours at the carotid bifurcation. Damage to the sympathetic innervation to the parotid gland can result in severe postoperative pain characterised by FBS and should be considered in all patients undergoing surgery involving the parapharyngeal space.

Large Intraosseous Schwannoma in Petrous Apex Presenting with Intratumoral Hemorrhage.

BACKGROUND: Intracranial schwannomas are rarely confined to the skull. We here report a large schwannoma localized in the petrous apex that presented with intratumoral hemorrhage. CASE DESCRIPTION: A 35-year-old woman with mild hearing disturbance and ear fullness underwent computed tomography scan and magnetic resonance imaging, which demonstrated a tumor accompanied with intratumoral hematoma in the right petrous apex. Bone marrow was totally destroyed, but the bone cortex was relatively preserved. Pathologic specimen showed that the tumor was composed of proliferation of elongated neoplastic cells and positive for S-100 protein. It showed a nuclear palisading pattern, compatible with schwannoma. The lack of any cranial nerve signs and relative preservation of canals through which cranial nerves pass suggested the neurilemma cells surrounded vessels or mismigrated fetal neurilemma cells in the petrous apex as origin of the tumor. Benign nature of the tumor and total disappearance of the symptoms, supposedly due to the spontaneous absorption of the hematoma, made the patient choose a wait-and-watch approach. Magnetic resonance imaging studied 7 years after the diagnosis showed significant decrease of the tumor volume and disappearance of the hematoma. CONCLUSIONS: Although it is a large intraosseous schwannoma in the petrous apex, it has a benign nature, its size is reduced due to the hematoma absorption, and the patient is asymptomatic. We observed the patients for 7 years after the diagnosis.

Characterization of Skull Base Lesions Using Pseudo-Continuous Arterial Spin Labeling.

PURPOSE: Pseudo-continuous arterial spin labeling (pCASL) is a non-invasive magnetic resonance (MR) perfusion technique. Our study aimed at estimating the diagnostic performance of the pCASL sequence in assessing the perfusion of skull base lesions both qualitatively and quantitatively and at providing cut-off values for differentiation of specific skull base lesions. METHODS: In this study 99 patients with histopathologically confirmed skull base lesions were retrospectively enrolled. Based on a pathological analysis, the lesions were classified as hypervascular and non-hypervascular. Patients were divided into two subgroups according to the anatomical origin of each lesion. The MRI study included pCASL and 3D T1-weighted fat-saturated post-contrast sequences. Of the patients seven were excluded due to technical difficulties or patient movement. The lesions were classified by two raters, blinded to the diagnosis as either hyperperfused or non-hyperperfused, based on the pCASL sequence. The normalized tumor blood flow (nTBF) of each lesion was determined. Qualitative and quantitative characteristics of hypervascular and non-hypervascular lesions were compared. RESULTS: Visual assessment enabled correct classification of 98% of the lesions to be performed. Quantitatively, we found significant differences between the nTBF values for hypervascular and non-hypervascular lesions (p < 0.001) and provided cut-off values, allowing meningioma and schwannoma to be distinguished from meningioma and adenoma. Significant differences were also found within the hypervascular group, namely, paraganglioma was more hyperperfused than meningioma (p = 0.003) or metastases (p = 0.009). CONCLUSION: The present study demonstrates the high diagnostic performance of pCASL in characterizing skull base lesions by either visual assessment or nTBF quantification. Adding the pCASL sequence to the conventional protocol of skull base assessment can be recommended.

Differential expression of angiogenic factors in peripheral nerve sheath tumors.

It is difficult to differentiate some malignant peripheral nerve sheath tumors (MPNST) from benign peripheral nerve sheath tumors (BPNST) histologically, and to predict the clinical outcome of patients with MPNST. In this study, the expression of VEGF and MVD were evaluated immunohistochemically in 22 cases of MPNST, 14 of neurofibroma and 19 of schwannoma and correlation of the staining grade of VEGF or MVD and the various clinical factors were analyzed, and statistically evaluated. Levels of VEGF mRNA expression were also determined with real-time RT-PCR. Statistically higher positive staining for VEGF was observed in MPNST compared to neurofibroma (P=0.004) and schwannoma (P<0.001). Even low grade MPNST showed higher VEGF positive staining than neurofibroma. Moreover, high VEGF expression statistically correlated with the poor prognosis of the patients with MPNST (P=0.015). Although MVD in MPNST was significantly higher than that in neurofibroma (P=0.038) and schwannoma (P<0.001), MVD could not predict the prognosis of the patients with MPNST. Although VEGF mRNA expression tended to be higher in MPNST compared to neurofibroma, the difference was not significant. Levels of VEGF protein expression serve as a novel diagnostic and prognostic tools for peripheral nerve sheath tumors.

[Pulmonary schwannoma with hypervascularity; report of a case].

A 54-year-old female was admitted to our hospital with a mass shadow in the right pulmonary hilum. The chest computed tomography (CT) scan revealed a well-circumscribed mass in the lower lobe of the right lung. Bronchoscopic examination showed a submucosal tumor in the right basal bronchus which bled easily, and the angiogram showed a tumor with hypervascularity. The tumor was suspected to be a sclerosing hemangioma or malignant tumor. A right basal segmentectomy was performed, and the pathological diagnosis was that of schwannoma. During the 8 year follow-up period, she exhibited no evidence of recurrence.

Hypoxia-induced miR-210 promoter demethylation enhances proliferation, autophagy and angiogenesis of schwannoma cells.

Hypoxia, a dominant feature in cancer occurrence and evolution, exists throughout the progression of most malignant tumors. This study focused on the mechanism of hypoxia-induced miR-210 upregulation, and the miR-210 functions in schwannoma. We detected microvascular density, vascular endothelial growth factor (VEGF) and miR-210 expression levels using schwannoma tissue mciroarray. The results showed that miR-210 expression was significantly associated with VEGF. Moreover, the cytological tests showed that hypoxia induced miR-210 expression, while reduce ephrin-A3 expression. The bisulfate genomic sequencing PCR results showed that miR-210 promoter region was hypermethylated in RT4-D6P2T in normoxia, while demethylated in hypoxia, and the region included the hypoxia-inducible factor-1α (HIF-1α) response element site. Cellular function research showed that hypoxia resulted in RT4-D6P2T apoptosis, higher autophage and invasion. Besides, hypoxia can affect HIF-1α/VEGF-mediated angiogenesis. To learn about the specific functions of miR-210, we found that with miR-210 inhibition, tumor cell apoptosis increased, autophagy and angiogenesis reduced, and the cell cycle was arrested. Hypoxia promoted miR-210 expression through promoter demethylation, then consequently enhanced tumor cell proliferation and autophagy, increasing tumor cell angiogenesis. Thus, miR-210 could be a potential marker for judging tumor malignancy and be taken as an effective target for clinical auxiliary treatment of neurilemmoma.

Sympathetic Chain Schwannoma Resembling Carotid Body Tumour.

Schwannomas are rare, benign nerve sheath tumours of parapharyngeal space. Differential diagnosis should include salivary gland tumours, paragangliomas, neurofibromas, and metastatic lymph nodes. The tumours may arise from vagus nerve and cervical sympathetic chain (CSC). Diagnosis is usually made by imaging techniques: contrast CT, magnetic resonance imaging (MRI), and magnetic resonance angiography (MRA). Fine needle aspiration cytology (FNAC) is useful diagnostic procedure but poor results are seen in neurogenic tumours. Rarely, a vascular CSC schwannoma at the level of carotid arteries bifurcation may mimic carotid body tumour (CBT) on imaging techniques, especially if they are vascular, causing splaying of internal and external carotid arteries. Clinically patient was asymptomatic except for a pulsatile swelling in neck for 5 years. The presented case resembled CBTclinically, on ultrasound and on imaging techniques causing splaying of carotid arteries. FNAC was inconclusive and was always hemorrhagic. During operation, it was found to be CSC schwannoma just posterior to carotid body. CSC was sacrificed and patient developed Horner syndrome postoperatively.

CT arteriography for orbital tumors: diagnostic and surgical value.

The aim of this study is to investigate the efficacy of dynamic computed tomography (CT) during selective angiography (CT-arteriography) of orbital tumors in the evaluation of intratumoral vascular anatomy, feeding artery territory, and histological diagnosis. Among 35 consecutive cases with various orbital lesions, those cases showing tumor staining or pooling of the contrast medium on digital subtraction angiography (DSA) were evaluated by CT-arteriography (n = 14). The information obtained by CT-arteriography was compared with that provided by enhanced MRI (n = 31) and dynamic MRI (n = 21), in which the contrast medium was injected intravenously. In addition to the visualization of fine vascular anatomy, CT-arteriography emphasized areas of nodular enhancement and non-enhancing cystic/necrotic components as well as the intratumoral feeding arteries. Patterns of CT-arteriography were categorized into three subgroups: homogeneous enhancement (benign lymphoid lesion), partial enhancement (schwannomas and carcinomas), and patchy multinodular enhancement (specific for cavernous angiomas). In addition, CT-arteriography with selective arterial catheterization clearly delineated the feeding artery territories. CT-arteriography, with a minimal dose of contrast medium, can offer significant advantages over intravenously injected dynamic neuroimaging, and provides additional valuable preoperative information about the orbital tumor under investigation.

Acute presentation of brachial plexus schwannoma secondary to infarction.

Schwannomas of the brachial plexus are rare and typically present as slowly growing masses. We describe a case of a 37-year-old female who presented with acute onset of severe left upper extremity pain. Magnetic resonance imaging (MRI) showed a 2.3 × 2.1 cm peripherally enhancing centrally cystic lesion in the left axilla, along the cords of the left brachial plexus, with significant surrounding edema and enhancement. The mass was surgically removed. Pathology was consistent with a schwannoma with infarction. The pain completely resolved immediately after surgery.

Histiocytoid endothelial cells in a malignant schwannoma.

Unusual vascular lining cells within a malignant schwannoma prompted a comparative study of these cells and the endothelial cells in cases of histiocytoid hemangiomas. The endothelial cells in all cases showed similar morphologic and immunohistochemical features. Such endothelial cells were not found in the capillaries of a pyogenic granuloma or in those of developing rat skin. It is postulated that these distinctive endothelial cells may be more widely distributed than was previously thought and that morphologic changes associated with these cells may be induced by vasoactive substances.

Infarcted spinal schwannoma: an unusual MR finding.

We present a case of infarcted schwannoma of the thoracic spine in a patient with acute cord compression. MR images did not enhance after contrast administration, which is highly atypical for schwannoma, but was in keeping with the pathologic findings in this case.