Intrathoracic malignant peripheral nerve sheath tumors: imaging features and implications for management

Impact of CT and MRI in the diagnostic workup of malignant triton tumour-a monocentric analysis and review of the literature

OBJECTIVES

Malignant triton tumours (MTTs) are rare but aggressive subtypes of malignant peripheral nerve sheath tumours (MPNSTs) with a high recurrence rate and 5-year survival of 14%. Systematic imaging data on MTTs are scarce and mainly based on single case reports. Therefore, we aimed to identify typical CT and MRI features to improve early diagnosis rates of this uncommon entity.

METHODS

A systematic review on literature published until December 2022 on imaging characteristics of MTTs was performed. Based on that, we conducted a retrospective, monocentric analysis of patients with histopathologically proven MTTs from our department. Explorative data analysis was performed.

RESULTS

Initially, 29 studies on 34 patients (31.42 ± 22.6 years, 12 female) were evaluated: Literature described primary MTTs as huge, lobulated tumours (108 ± 99.3 mm) with central necrosis (56% [19/34]), low T1w (81% [17/21]), high T2w signal (90% [19/21]) and inhomogeneous enhancement on MRI (54% [7/13]). Analysis of 16 patients (48.9 ± 13.8 years; 9 female) from our institution revealed comparable results: primary MTTs showed large, lobulated masses (118 mm ± 64.9) with necrotic areas (92% [11/12]). MRI revealed low T1w (100% [7/7]), high T2w signal (100% [7/7]) and inhomogeneous enhancement (86% [6/7]). Local recurrences and soft-tissue metastases mimicked these features, while nonsoft-tissue metastases appeared unspecific.

CONCLUSIONS

MTTs show characteristic features on CT and MRI. However, these do not allow a reliable differentiation between MTTs and other MPNSTs based on imaging alone. Therefore, additional histopathological analysis is required.

ADVANCES IN KNOWLEDGE

This largest published systematic analysis on MTT imaging revealed typical but unspecific imaging features that do not allow a reliable, imaging-based differentiation between MTTs and other MPNSTs. Hence, additional histopathological analysis remains essential.

Surgical management of craniospinal axis malignant peripheral nerve sheath tumors: a single-institution experience and literature review

BACKGROUND

Malignant peripheral nerve sheath tumor (MPNST) is an exceedingly rare and aggressive tumor, with limited literature on its management. Herein, we present our series of surgically managed craniospinal MPNSTs, analyze their outcomes, and review the literature.

METHODS

We retrospectively reviewed surgically managed primary craniospinal MPNSTs treated at our institution between January 2005 and May 2023. Patient demographics, tumor features, and treatment outcomes were assessed. Neurological function was quantified using the Frankel grade and Karnofsky performance scores. Descriptive statistics, rank-sum tests, and Kaplan-Meier survival analyses were performed.

RESULTS

Eight patients satisfied the inclusion criteria (4 male, 4 female). The median age at presentation was 38 years (range 15-67). Most tumors were localized to the spine (75%), and 3 patients had neurofibromatosis type 1. The most common presenting symptoms were paresthesia (50%) and visual changes (13%). The median tumor size was 3 cm, and most tumors were oval-shaped (50%) with well-defined borders (75%). Six tumors were high grade (75%), and gross total resection was achieved in 5 patients, with subtotal resection in the remaining 3 patients. Postoperative radiotherapy and chemotherapy were performed in 6 (75%) and 4 (50%) cases, respectively. Local recurrence occurred in 5 (63%) cases, and distant metastases occurred in 2 (25%). The median overall survival was 26.7 months. Five (63%) patients died due to recurrence.

CONCLUSIONS

Primary craniospinal MPNSTs are rare and have an aggressive clinical course. Early diagnosis and treatment are essential for managing these tumors. In this single-center study with a small cohort, maximal resection, low-grade pathology, young age (< 30), and adjuvant radiotherapy were associated with improved survival.

Computed tomography imaging features of malignant 'triton' tumor to facilitate its clinical diagnosis: report of two cases

Background

Malignant ‘triton’ tumor is an extremely rare subtype of malignant periphery nerve sheath tumors. Clinical diagnosis of malignant triton tumor is difficult before surgery due to its low incidence and the lack of knowledge. Therefore, to describe and summarize the CT imaging characteristics of malignant triton tumor is of great assistance for early and preoperative diagnosis.

Case presentation

Two cases suspected of MTT by CT scan before operation were closely observed. The diagnosis of malignant triton tumor was eventually confirmed by immunochemical assay, which verified speculation of CT scans. Huge, irregular, well-circumscribed lobulated mass-like shadows can be observed from these patients by CT scans. Besides, heterogeneity of density within the body of tumor was well-established by CT scans, together with linear septum. Meanwhile, CT scans demonstrated that calcifications were remarkable at the margin of tumor body.

Conclusions

Some CT image features from two cases were presented as a reference for the preoperative consideration of MTT: (i) enormity of mass-like shadow; (ii) presence of well-circumscribed lobulated shape; (iii) septum within the well-defined mass accompanied with hemorrhage, necrosis and cystic changes as well as calcification, especially within neurofibromatosis type 1 patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12880-022-00848-9.

Missing the Forest for the Trees - A Rare Cause of Pleural Effusion

Neurofibromatosis type 1 (NF-1) is a genetic disorder associated with dermatological, musculoskeletal, and neurological features. Apart from these, knowledge of other uncommon manifestations, including intrathoracic and pulmonary involvement, is crucial for early diagnosis and treatment. These patients are predisposed to various sarcomatous and non-sarcomatous malignancies. We report the case of an elderly lady with NF-1 who presented with pleural effusion related to the genetic disorder, which was missed, and elaborate on the diagnostic workup done to reach a diagnosis.

Metastatic malignant peripheral nerve sheath tumor. A diagnostic surprise

Malignant peripheral nerve sheath tumours (MPNSTs) are rare soft tissue tumors that arise from pre-existing plexiform neurofibromas or within a normal peripheral nerve. They are aggressive tumors with high rates of recurrence and distant metastases, the most common sites of metastasis being the lung followed by bone. A 46 year old gentleman presented with breathlessness and chest pain three years after post amputation of left thumb for an ulcerative growth. CECT thorax showed a left upper lobe mass with pleural and pericardial effusion. Within a month of presentation he worsened and succumbed to the disease. Antemortem biopsy of the left hand ulcerative growth showed features suggestive of malignant peripheral nerve sheath tumour- epithelioid variant and post mortem liver and lung biopsy showed metastasis of MPNST. The diagnosis was a malignant peripheral nerve sheath tumor with lung, liver and cardiac metastasis. This case report aims to highlight the importance of upfront aggressive multimodality local therapy for achieving local disease control in patients presenting with localised MPNST and regular follow up for early detection of relapse and metastasis.

FDG PET/CT of an Advanced Case of Malignant Nerve Sheath Tumor of Pleura

ABSTRACT

We present a rare case of malignant nerve sheath tumor of pleura referred for the evaluation of metastases and local invasion. FDG PET/CT demonstrated a hypermetabolic tumoral lesion extensively involving the right pleura with no involvement of mediastinal structures or pulmonary parenchyma and no clear evidence of distant metastasis. Malignant nerve sheath tumor of pleura is an extremely rare entity, and FDG PET/CT is valuable in demonstrating the extent of disease and can have potential role for postsurgical as well as postchemotherapy assessment of possible residual disease.

Primary Intrathoracic Sarcomas: A Review of Cross-sectional Imaging and Pathology

The most common sarcomas in the thorax are metastasis from an extrathoracic primary malignancy. Primary intrathoracic sarcomas are rare albeit aggressive malignancies that are diagnosed on histopathology. Although a few imaging characteristics have been described that are common to sarcomas, it is still a diagnosis of exclusion as other tumors are much more common. Like elsewhere, primary thoracic sarcomas are also classified according to their histologic features. They are a rare group of tumors that can arise from the mediastinal structures, lung, pleura, or chest wall. On imaging, differentiating these from more common malignancies like lung cancer is difficult and often requires multimodality workup and tissue sampling. A few sarcomas are very specific to their locations, such as angiosarcoma in the right atrium, leiomyosarcoma in the pulmonary artery, where imaging has high accuracy for the diagnosis. Despite being nonspecific in a majority of cases, imaging plays a pivotal role in determining the organ of origin, tumor extent, invasion of adjacent structures, and thus help to assess the surgical resectability. Although sarcomas arising from chest wall are the most common primary sarcomas in the chest, they are excluded from this review to focus only on primary intrathoracic sarcomas. The article provides a comprehensive imaging and pathology review of the rare primary intrathoracic sarcomas, including but not limited to angiosarcoma, Kaposi sarcoma, fibrosarcoma, malignant transformation of fibrous tumor of pleura, sarcomatoid mesothelioma, leiomyosarcoma, and malignant small round blue cell tumors.Key points:Primary intrathoracic sarcomas are rare but clinically important.Imaging helps to determine local extent, invasion, metastases and appropriate site/mode of biopsy.Role of pathology is paramount in diagnosis and guiding treatment based on immunogenetic/molecular typing.

Giant intrapulmonary malignant peripheral nerve sheath tumour

Pulmonary malignant peripheral nerve sheath tumours (MPNSTs) are extremely rare soft tissue sarcomas that develop from the cell constituting the nerve sheaths, approximately 5-10% of all soft tissue sarcomas. We present a rare case of primary lung MPNST in an adult female non-smoker patient, in whom surgical thoracotomy approach has obtained a good control of the disease. Low-grade MPNST was established from excisional biopsy followed by immunohistochemistry.

Successful Management of Intrathoracic Phrenic Malignant Peripheral Nerve Sheath Tumor by Multimodal Treatment

Malignant peripheral nerve sheath tumors (MPNSTs) are rare and can be associated with type 1 neurofibromatosis. They are rarely located at the mediastinum, most often at the posterior mediastinal compartment or the paravertebral gutters. MPNSTs of the anterior mediastinum arising from the phrenic nerve are exceptional. Their prognosis is poor due to the high potential of local tumor recurrence and metastasis. Complete surgical resection remains the only radical treatment. However, the outcomes after this treatment alone cannot be considered satisfactory. Preoperative chemotherapy could be an interesting therapeutic option for unresectable tumors. We report here the case of a 77-year-old woman with an MPNST located at the anterior mediastinum arising from the phrenic nerve. This tumor was successfully managed with multimodal therapy combining preoperative chemotherapy, complete surgery and adjuvant radiation.

Clinical presentation and long-term outcome of primary spinal intradural malignant peripheral nerve sheath tumors

OBJECTIVE

Primary spinal intradural malignant peripheral nerve sheath tumors (MPNSTs) are exceedingly rare, and there is limited published information regarding these lesions. The purpose of this study was to analyze the clinical course, treatment, and outcome of primary spinal intradural MPNSTs.

PATIENTS AND METHODS

A retrospective study was performed on 8 patients with primary spinal intradural MPNSTs who were surgically treated and pathologically confirmed in our institution between 2007 and 2018.

RESULTS

There were 3 females and 5 males, with a median age of 46.5 years (range, 21-68 years). Limb weakness was the most common clinical symptom (5/8, 62.5%). The radiological diagnosis was meningioma or schwannoma in most patients (7/8, 87.5%). Malignancies were graded high in 5 cases (62.5%) and low in 3 cases (37.5%). Gross total resection (GTR) was performed in 5 cases, while subtotal resection (STR) was achieved in 3 cases. The mean follow-up period was 48.9 months (range, 10-160 months). During follow-up, local recurrence occurred in 6/8 cases (75.0%) and distant metastasis occurred in 2/8 cases (25.0%). The median survival time (MST) of these 8 patients was 21.0 months. The overall 1-year, 2-year, and 5-year survival rates were 87.5% (7/8), 50.0% (4/8), and 25.0% (2/8), respectively.

CONCLUSIONS

Primary spinal intradural MPNST is a challenging clinical entity given its high local relapse rate. Primary spinal intradural MPNSTs radiologically present themselves heterogeneous and thus difficult to distinguish from schwannomas or meningiomas. Surgical resection, especially GTR, is the preferential treatment for primary spinal intradural MPNSTs.

Evaluation of the most commonly used (semi-)quantitative parameters of 18F-FDG PET/CT to detect malignant transformation of neurofibromas in neurofibromatosis type 1

In patients with neurofibromatosis type 1, transformation of neurofibromas into a malignant peripheral nerve sheath tumor (MPNST) is a severe complication of the disease. Fluorine-18-fluorodeoxyglucose PET/computed tomography (PET/CT) is a viable option for detecting malignant tumors in neurofibromatosis type 1 patients. The aim of this review was to assess the diagnostic performance of the most frequently used parameters of PET/CT in detecting MPNST. An extensive computer search was performed using the Cochrane Library, Pubmed, and Medline/Embase databases. Two reviewers independently extracted data of relevant studies and assessed the methodological quality (QUADAS-2). The diagnostic performance of PET/CT parameters in individual studies was determined by calculating a diagnostic odds ratio (DOR) using the absolute numbers of true-positive, true-negative, false-positive, and false-negative test results. A total of eight studies were included, of which three evaluated the standardized uptake value as a diagnostic parameter, two assessed the tumor-to-liver (T/L) ratio, and three articles described both parameters. The cut-off values for maximum standardized uptake value (SUVmax) ranged from 3.2 to 4.5; for the T/L ratio, the cut-off values were between 1.0 and 4.3. The sensitivity and specificity ranged from 90 to 100% and from 80 to 100%, respectively (SUVmax). T/L ratios were associated with 92-100% sensitivity and 72-94% specificity. The corresponding DORs ranged from 57 to 145 (SUVmax) and 35 to 655 (T/L ratio). Both the SUV and the T/L ratio are associated with high sensitivity combined with acceptable specificity in detecting MPNST. There is a tendency toward higher DORs using the T/L ratio, but the number of studies is limited.

Successful treatment with doxorubicin and ifosfamide for mediastinal malignant peripheral nerve sheath tumor with loss of H3K27me3 expression

Malignant peripheral nerve sheath tumor (MPNST) in the thorax is an extremely rare disease, and half of all cases of MPNST are associated with neurofibromatosis type I. Sporadic intrathoracic MPNST is difficult to diagnose and treat. Because of the rarity of intrathoracic MPNST, the optimal method of diagnosis and the efficacy of chemotherapy are unknown. Herein, we present a case of inoperable mediastinal MPNST, in which the diagnosis was immunohistochemically made by the loss of H3K27me3 expression in a transbronchial needle biopsy specimen. The patient showed a good response to doxorubicin plus ifosfamide chemotherapy. The present case highlights that MPNST should be included in the differential diagnosis of non‐posterior mediastinum thoracic lesions, and that appropriate diagnosis and treatment for intrathoracic MPNST should be considered in patients with a thoracic mass.

A 40-Year-Old Woman With Back Pain

A 40-year-old woman consulted our ED for a 7-month history of left dorsal back pain and dyspnea. The pain was initially dull and mechanical. Her general practitioner started nonsteroidal antiinflammatory drugs and physiotherapy, which provided partial relief. One week before consulting, the intensity of the pain increased, and she started to feel shortness of breath when performing her daily activities. She had lost 5 kg during the previous month. The patient was a healthy woman who lived in an urban area of Barcelona, Spain. She did not smoke or take drugs of abuse, and she worked as a butcher. During the initial evaluation, her blood pressure was 131/76 mm Hg, heart rate was 120 beats/min, temperature was 36.2°C, and ambient air pulse oximetry was 98%.

Imaging of Thoracic Neurogenic Tumors

OBJECTIVE

Thoracic neurogenic neoplasms may be a diagnostic challenge both clinically and radiologically, ranging from benign, incidentally discovered tumors to aggressive, symptomatic malignancies. These tumors may originate from any nervous structure within the chest and are derived from cells of the nerve sheath, autonomic ganglia, or paraganglia. The nervous anatomy of the thorax is complex, and neurogenic tumors may be found in any mediastinal compartment or in the chest wall. Furthermore, neurogenic tumors may indicate one of many syndromes, particularly when they are multiple.

CONCLUSION

This article illustrates the complex anatomy of the nervous system within the chest and details important epidemiologic and pathophysiologic features as an approach to neurogenic tumors of the thorax. Key imaging features of neurogenic tumors occurring in the chest are identified, focusing on distinguishing characteristics and the relative advantages of available imaging modalities to further refine a differential diagnosis.

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.

Soft-Tissue Sarcomas: An Update for Radiologists Based on the Revised 2013 World Health Organization Classification

OBJECTIVE

Soft-tissue sarcomas are a diverse group of malignancies, and our rapidly improving understanding of their molecular pathogenesis and treatment is leading to better clinical outcomes. The revised 2013 World Health Organization (WHO) classification of soft-tissue sarcomas introduced several important changes. We provide a comprehensive overview of the relevant changes for radiologists.

CONCLUSION

Rapid advances in the understanding of the pathogenesis and molecular biology of soft-tissue sarcomas led to major revisions in the 2013 WHO classification. To provide optimal multidisciplinary patient care, radiologists must remain up-to-date with the latest developments in the field of soft-tissue sarcomas to best correlate the histologic and imaging features of the various types of tumors and understand the unique patterns of treatment response and disease recurrence.

Intrathoracic peripheral nerve sheath tumors-a clinicopathological study of 75 cases

Although peripheral nerve sheath tumors (PNSTs) are common in the posterior mediastinum, they are rare in other mediastinal compartments and in the pleuropulmonary parenchyma. We sought to characterize the clinicopathological features of PNSTs occurring in the lung, pleura, and mediastinum. Diagnoses were confirmed by slide review. Study cases include 21 benign pleuropulmonary PNSTs, 49 benign mediastinal PNSTs, and 5 malignant PNSTs. Benign pleuropulmonary tumors comprised 13 schwannomas, 6 neurofibromas, 1 perineurioma, and 1 ganglioneuroma. Six lesions were endobronchial (3 neurofibromas, 1 schwannoma, 1 perineurioma, 1 ganglioneuroma), whereas the remaining schwannomas and neurofibromas formed parenchymal masses (usually pleural based). Benign mediastinal PNSTs (46 posterior, 2 middle, and 1 anterior) were all schwannomas and showed a female predominance. None of the patients with benign PNSTs experienced recurrence. Of the 5 malignant PNSTs, 4 were pleuropulmonary (3 pleural based) and 1 occurred in the anterior mediastinum. Two of the 5 patients had a history of neurofibromatosis type 1 (aged 27 and 45 years). At last follow-up, 3 of the 5 patients had died of disease, 1 was alive with disease, and 1 was alive with no evidence of disease (41 months). Although rare, a wide histologic range of PNSTs occur in the lung. Although neurofibroma, perineurioma, and ganglioneuroma were observed as endobronchial lesions, most pulmonary schwannomas were pleural-based masses. Mediastinal PNSTs are dominated by posterior mediastinal schwannomas, although schwannomas rarely occur in the other mediastinal compartments as well. Malignant PNSTs are very rare in the thorax, where they show aggressive behavior.

Nerve-sparing schwannoma removal from two infrequent origins

Schwannomas of nerve sheath origin (Schwann cell) are the most common neurogenic thoracic tumors and they usually originate from an intercostal nerve, especially in the paravertebral region. Tumors that originate from other nerves such as the phrenic nerve, vagus, or sympathetic nerves are uncommon. We report two cases of schwannomas in rare locations. A 62-year-old woman had a giant schwannoma arising from the right phrenic nerve, and a 57-year-old woman had one from the left sympathetic nerve. Both tumors were completely removed with preservation of the nerves.