Imaging of the malignant peripheral nerve sheath tumour with emphasis οn ultrasonography: correlation with MRI

Cubital tunnel syndrome: anatomy, pathology, and imaging

Cubital tunnel syndrome (CuTS) is the second most common peripheral neuropathy in the upper limb. It occurs due to ulnar nerve compression within the fibro-osseous cubital tunnel at the elbow joint. Although CuTS is typically diagnosed clinically and with electrodiagnostic studies, the importance of imaging in evaluating the condition is growing. Knowing the typical imaging findings of ulnar nerve entrapment is necessary for precise diagnosis and proper treatment. In this article, we focus on the clinical features, workup and complex imaging of the "anatomic" cubital tunnel and relevant pathological entities.

Malignant and Benign Peripheral Nerve Sheath Tumors in a Single Center: Value of Clinical and Ultrasound Features for the Diagnosis of Malignant Peripheral Nerve Sheath Tumor Compared With Magnetic Resonance Imaging

OBJECTIVES

This study aimed to investigate the combined use of ultrasonography and clinical features for the differentiation of malignant peripheral nerve sheath tumors (MPNST) from benign peripheral nerve sheath tumors (BPNST) and to compare the efficacy of ultrasonography with that of magnetic resonance imaging (MRI).

METHODS

This retrospective study included 28 MPNSTs and a control group of 57 BPNSTs. All patients underwent an ultrasound scan using the Logiq E9 (GE Health Care, Milwaukee, WI) or EPIQ7 equipment (Philips Medical System, Bothell, WA). A 3.0-T MRI machine (Ingenia; Philips Healthcare, Best, the Netherlands) was used for scanning, and conventional MRI was performed on different regions based on the patient's clinical situation. The following variables were evaluated: palpable mass, pain, nerve symptoms, maximum diameter, location, shape, boundary, encapsulation, echogenicity, echo homogeneity, presence of a cystic component, calcification, target sign, posterior echo, and intertumoral vascularity of the tumors. The diagnostic efficacy of ultrasonography and clinical factors was compared with that of MRI. Independent factors for predicting MPNST versus BPNST were also assessed.

RESULTS

The parameters of location, shape, boundary, encapsulation, and vascularity were significantly different between MPNSTs and BPNSTs. Multiple logistic regression analysis showed that shape, boundary, and vascularity were independent predictors of MPNSTs. The sensitivity, specificity, and Youden index of the three clinical and ultrasound factors (shape, boundary, and vascularity) were 0.89, 0.81, and 0.69, respectively, whereas those of MRI were 0.71, 0.89, and 0.61, respectively. No significant differences in the area under the curve (AUC) of the three combined clinical and ultrasound factors and those of MRI were found (P > .05).

CONCLUSIONS

MRI was useful in the differential diagnosis between MPNSTs and BPNSTs. However, the combination of clinical and ultrasound diagnoses can achieve the same effect as MRI, including shape, boundary, and vasculature.

Investigation of Ultrasound Parameters for the Differential Diagnosis of Malignant and Benign Peripheral Nerve Sheath Tumors

OBJECTIVES

The objectives were to identify the key features of malignant and benign peripheral nerve sheath tumors (PNSTs) and determine a strategy for differentiating them using sonography.

METHODS

Forty-six malignant peripheral nerve sheath tumors (MPNSTs) and 83 benign peripheral nerve sheath tumors (BPNSTs) confirmed by pathology from April 2010 to July 2021 were included. The general data and grayscale and color Doppler ultrasonic manifestations were compared between the two groups. We used single factor, multifactor, and area under the receiver operating characteristic (ROC) curve analyses to extract significant malignant risk factors and then established a scoring system with these factors.

RESULTS

The significant variables identified in univariate analysis (P < .05) were maximum diameter, location, shape, boundary, encapsulation, echogenicity, texture pattern, calcification, entering or exiting nerve, and vascularity. Shape, boundary and vascularity were significant risk factors, and a scoring system was established. The area under the ROC curve (0.925) confirmed the usefulness of the scoring system for differentiating MPNSTs and BPNSTs.

CONCLUSIONS

Ultrasonography is an effective method for differentiating MPNSTs from BPNSTs.

Synovial sarcoma of the spinal canal and paraspinal muscle and retroperitoneum: a case with extensive calcification

INTRODUCTION

Synovial sarcoma (SS) is a rare mesenchymal malignant tumor. SS of the spine or retroperitoneum is an extremely rare site. Approximately 30% cases show focal calcifications on radiographs and computed tomography (CT) images, while extensive calcification rarely occurs. We presented a case of SS involving the spinal canal and paraspinal muscle and retroperitoneum, which showed extensive calcification on CT.

CLINICAL PRESENTATION

The present report describes the case of a 13-year-old girl suffering from a tumor in the spinal canal and paraspinal muscle and retroperitoneum with extensive calcification on CT. The patient underwent lumbar and retroperitoneal giant tumor resection, lumbar decompression, and spinal tumor resection with a small tumor remnant remaining in the paravertebral region. Histological examination and genetic testing after surgery confirmed synovial sarcoma. After surgery, the patient refused local radiotherapy but agreed to receive chemotherapy. After 4 months of follow-up, her condition was basically stable, and the pain in her left lower limb disappeared. The residual tumor was not increased.

CONCLUSION

Extensive calcification of SS is rare. The possibility of synovial sarcoma should be considered in those who show extensive calcification in the spinal canal and paraspinal muscle and retroperitoneum on CT. For cases that cannot be completely resected, adjuvant chemotherapy can control the residual tumor in the short term. In addition, the long-term effects need to be observed.

Imaging of Pediatric Soft Tissue Tumors and Tumor-like Conditions

Lumps and bumps are frequently seen in children, and the vast majority are a result of trauma, infection, or inflammation. True soft tissue neoplastic lesions are rare; however, their wide and complex classifications make these lesions challenging to manage. Imaging features are usually nonspecific, and a reasonable list of differential diagnoses can be generated following consideration of the clinical presentation, age, and anatomical location of the lesion. In this article, we offer a practical approach to diagnosing such lesions by discussing the most common three benign and malignant lesions in different anatomical regions stratified by age with emphasis on certain features that might aid in the diagnosis such as depth, multiplicity, calcification, or other specific imaging feature.

Malignant Peripheral Nerve Sheath Tumor in an Army Reservist With Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is an autosomal dominant condition affecting 1 in 3,500 people resulting from an NF1 gene mutation that encodes the nonfunctional protein neurofibromin mutant. Neurofibromin is a negative regulator of RAS signaling involved in cell survival and proliferation. NF1 typically presents at birth or in early childhood with multiple light brown (café au lait) spots and axillary freckling. With age, patients may develop scattered neurofibromas as well as additional neurological and malignant abnormalities. Additionally, the nonfunctional protein neurofibromin mutant may be involved in the pathogenesis of peripheral malignant nerve sheath tumors, which is a rare and life-threatening complication of NF1. While a disqualifying condition for military duty, it may not initially be clinically apparent until complications develop. Here, we present a case of malignant peripheral sheath in an U.S. Army African American reservist with NF1 in whom cutaneous manifestations of NF1 such as café au lait spots and axillary freckling were not identified on the initial military entrance processing examination.

Primary synovial sarcomas in the paediatric and young adult population: A pictorial review

PURPOSE

To present a pictorial essay of paediatric primary synovial sarcomas from common and less documented anatomical locations. To review the literature for the imaging characteristics and prognostic factors of this rare but important childhood malignancy.

METHOD

24 primary synovial sarcoma cases (17 male, 7 female with an age range 4-21 years) were reviewed in a collaborative effort between St Jude Children's Research Hospital and Great Ormond Street Hospital for Children. Images from 19 cases were selected for inclusion, to demonstrate the spectrum of appearances across imaging modalities, in a range of different anatomical locations (upper limb, lower limb, chest/abdomen/pelvis, and head and neck). A literature review depicting the typical radiological features and the prognostic significance of these features, was also conducted.

RESULTS AND CONCLUSIONS

Primary synovial sarcoma can occur in any anatomical location, but typically within the extremities and often in close association with joints. Rarer anatomical locations described in our essay include the gastrohepatic ligament and femoral nerve sheath. We detail the salient imaging characteristics, including the T2 'triple signal' pattern which is believed to be highly specific for this particular sarcoma and in many cases predicts a poor outcome. Other poor prognostic factors include haemorrhage, lack of calcification and tumour size >10 cm. A broad range of radiological appearances are described, and in some cases related to anatomical position and size, however the presence of a soft tissue mass close to a joint in a young patient are suggestive of this diagnosis.

Overview of the clinical and imaging features of the most common non-rhabdomyosarcoma soft-tissue sarcomas

Non-rhabdomyosarcoma soft-tissue sarcoma (NRSTS) refers to a widely heterogeneous group of extraskeletal mesenchymal neoplasms accounting for approximately 4% of all childhood cancers. This article summarizes the clinical and imaging features of these rare tumors and describes in detail the three most common histological types of NRSTSs encountered in children - synovial sarcoma, malignant peripheral nerve sheath tumor and infantile fibrosarcoma. The author discusses the role of non-cross-sectional and cross-sectional imaging.

Radiological findings of malignant peripheral nerve sheath tumor: reports of six cases and review of literature

Background

Malignant peripheral nerve sheath tumor (MPNST) is a kind of rare neurogenic tumor. If associated with neurofibromatosis type 1, MPNST usually has a higher mortality. The aim of the article is to assess the imaging characteristics of MPNST and compare them with those of benign peripheral nerve sheath tumor (BPNST) to characterize this tumor.

Methods

Clinical and imaging data of six cases with MPNST and 28 cases with BPNST in our institution since 2011 were retrospectively reviewed. Thirty-three patients have available MR imaging data, and two patients of MPNST also accepted CT scan. One patient accepted CT scan only. Location, size, shape, signal or density, boundary, bone destruction, relation to adjacent nerve, contrast-enhanced features as well as some other signs were assessed and compared with statistical software. Student’s t test was used for comparison of continuous variables. Fisher’s exact test was used for analysis of nominal variable. A P value ≤0.05 was considered to be statistically significant.

Results

Differences existed between two groups in tumor size ((7.2 ± 3.3)cm in MPNST vs. (3.8 ± 1.4)cm in BPNST), unclear margin (4/6 in MPNST vs. 1/28 in BPNST), eccentricity to the nerve (1/6 in MPNST vs. 21/28 in BPNST), intratumoral lobulation (4/6 in MPNST vs. 2/28 in BPNST), peritumoral edema (3/6 in MPNST vs. 0 in BPNST), and peripheral enhancement (4/6 in MPNST (three of five MR, one CT) vs. 4/28 in BPNST). Bone destruction was observed in one MPNST.

Conclusions

MR imaging is a valuable, non-invasive modality for the diagnosis of MPNST. Peripheral enhancement with non-cystic appearance or remarkable heterogeneous enhancement may be useful for differential diagnosis. Other imaging features such as large size (over 5 cm in diameter), ill-defined margin, intratumoral lobulation, peritumoral edema, and adjacent bone destruction are also supportive of MPNST.