Soft tissue tumours: imaging strategy

Fat-Containing Soft Tissue Tumors in Children, Adolescents, and Young Adults: Which Require Biopsy?

PURPOSE

To confirm the overall benignity of fat-containing soft tissue tumors (STT) on a pediatric cohort and to define the clinical and imaging features that warrant a biopsy.

METHODS

A retrospective monocentric study was conducted on patients aged less than 25 years consecutively referred for fat-containing STT to our Comprehensive Cancer Center between 1998 and 2022. Tumor imaging characteristics at diagnosis (US, CT, or MRI) were correlated with pathology.

RESULTS

The database extraction identified 63 fat-containing tumors with clinical, histologic, and imaging data available for review. In total, 58 (92%) were benign tumors: 36 lipoblastomas and lipomas, 12 fibrous hamartomas of infancy (FHI), 5 lipofibromatosis, 2 lipomas arborescens, 2 lipomatosis and 1 spindle-cell lipoma. Five patients (8%) were diagnosed with liposarcoma. Factors significantly correlated with malignancy were age >10 years old (p < 0.001), having a cancer-predisposing condition (p < 0.001), a percentage of fat <25% (p = 0.002), and a presence of myxoid zones (p < 0.001) on imaging.

CONCLUSION

Most fat-containing STT in children may be classified as benign tumors based on clinics and imaging. The indication for biopsy could be limited to patients aged 10 years or more with either a cancer-predisposing condition or imaging features demonstrating either a low-fat component (<25%) or the presence of myxoid zones.

Non-parameningeal head and neck rhabdomyosarcoma in children, adolescents, and young adults: Experience of the European paediatric Soft tissue sarcoma Study Group (EpSSG) - RMS2005 study

BACKGROUND/OBJECTIVES

The primary aim of this study was to analyse and evaluate the impact of different local treatments on the pattern of relapse in children with primary head and neck non-parameningeal (HNnPM) rhabdomyosarcoma (RMS), treated in the European paediatric Soft tissue sarcoma Study Group (EpSSG) RMS2005 study. The secondary aim was to assess whether current risk stratification is valid for this specific site.

DESIGN/METHODS

This study includes all patients with localised HNnPM RMS enrolled in the RMS2005 study between 2005 and 2016. Treatment comprised chemotherapy adapted to risk group, with local surgery and/or radiation therapy. The main outcome measures were event-free survival (EFS) and overall survival (OS).

RESULTS

A total of 165 patients were identified; the median age was 6.4 years (range, 0.1-25). The most common tumour sites were cheek/chin (22%) and nasal ala/nasolabial fold (20%). Histology was unfavourable for 40%, and regional nodal involvement present in 26%. Local therapy included surgery (58%) and/or radiotherapy (72%) to primary tumour and/or regional lymph nodes. After a median follow-up of 66 months (range, 6-158), 42 patients experienced an event, and 17 are still alive. Tumour events were frequent in oral primary (36%), parotid site (26%), cheek/chin (24%), and nasal ala/nasolabial fold (24%) and included locoregional failure in 84% of cases. The 5-year EFS and OS were 75% (95% confidence interval [CI]: 67.3-81.2) and 84.9% (95% CI: 77.5-89.7), respectively. Favourable histology was associated with a better EFS (82.3% versus 64.6%; p = 0.02) and nodal spread with a worse OS (88.6% versus 76.1%; p = 0.04). Different sublocations within the HNnPM primary did not have significant impact on outcome.

CONCLUSION

Locoregional relapse/progression is the main tumour failure event in this site. Despite frequent unfavourable risk factors, HNnPM RMS remains a favourable location in the context of a risk-adapted strategy.

Configuration of soft-tissue sarcoma on MRI correlates with grade of malignancy

BACKGROUND

The aim of the study was to assess whether the configuration of primary soft-tissue sarcoma (STS) on MRI correlates with the grade of malignancy.

PATIENTS AND METHODS

71 patients with histologically proven STS were included. Primary STS were examined for configuration, borders, and volume on MRI. The tumors were divided into high-grade (G3), intermediate-grade (G2) and low-grade (G1) STS according to the grading system of the French Federation of Cancer Centers Sarcoma Group (FNCLCC).

RESULTS

30 high-grade, 22 intermediate-grade and 19 low-grade primary STS lesions were identified. High- and intermediate-grade (G3/2) STS significantly most often appeared as polycyclic/multilobulated tumors (p < 0.001 and p = 0.002, respectively). Low-grade (G1) STS mainly showed an ovoid/nodular or streaky configuration (p = 0.008), and well-defined borders. The appearance of high-, intermediate- and low-grade STS with an ovoid/nodular configuration were mainly the same on MRI. All streaky G3/2 sarcoma and 17 of 20 patients with polycyclic/multilobulated G3 sarcoma showed infiltrative borders. High-grade streaky and polycyclic/multilobulated STS are larger in volume, compared to intermediate- and low-grade STS.

CONCLUSIONS

Configuration of STS on MRI can indicate the grade of malignancy. Higher-grade (G2/3) STS most often show a polycyclic/multilobulated configuration, while low-grade STS are mainly ovoid/nodular or streaky. Infiltrative behavior might suggest higher-grade STS in streaky and polycyclic/multilobulated STS.

Head and neck tumors in children and adolescents: Impact of a multidisciplinary tumor board

INTRODUCTION

Cancer treatment in France is based on Multidisciplinary Tumor Board (MTB). In the Ile-de-France region (IDF), which includes 12 million inhabitants from Paris and the surrounding area, pediatric tumors of head and neck are discussed since 2013 in a dedicated Interregional Pediatric Multicentric MTB (IPMTB). The purpose of this study is to analyze the impact of the IDF head and neck IPMTB on the management of these tumors, 5 years after their implementation.

MATERIALS AND METHODS

Retrospective study of all patient files presented in the IPMTB for a benign or malignant head-and-neck tumor, between 2013 and 2018.

RESULTS

A total of 679 discussions were analyzed representing 428 patients. Median age was 7.5 years (range: 0-31 years). Malignant tumors represented 71% of cases, including 36% of rhabdomyosarcoma. Overall, 12% percent of the cases discussed came from centers outside of IDF. All meetings complied with multidisciplinary criteria required by French law. Proposals made during the IPMTB were followed in 86% of cases. Among the 251 proposals made by the referring teams prior to the IPMTB, 29% were secondarily modified after being discussed in the IPMTB.

CONCLUSION

Thanks to their multidisciplinarity, high number of cases discussed and usual respect of their proposals, the IPMTB have made it possible to improve the coordination between all specialties involved in the patient's management, to apply the most recent and scientifically validated protocols, and to share the knowledge of different teams concerning the management of particularly rare tumors.

Cervical Infantile Fibrosarcoma: a rare cause of paediatric parapharyngeal neck mass

Soft tissue tumors are not uncommon in childhood and comprise entities that range from common to very rare malignancies. Infantile fibrosarcoma (IFS) is a rare pediatric malignancy mainly seen in the first two years of life. The data about the incidence of infantile fibrosarcoma occurring in the neck in the Indian subcontinent is scarce. To the best of our knowledge, only one case of infant cervical IFS has been reported previously in the Indian subcontinent. We present another case of an eight-year-old male patient with a rapidly growing mass on the left side of the neck. He was successfully treated with a combined modality of surgery and chemotherapy with a good outcome. Among the soft tissue tumors of childhood, IFS is a rare entity. It has a good prognosis and lesser chance of distant metastasis as compared to adult fibrosarcoma. Though surgical excision is the mainstay of treatment, chemotherapy also has a significant role in the treatment of primary tumor and metastasis. We discuss the stated case to bring to the notice this uncommon cause, which can be considered as a differential diagnosis of upper cervical swellings. A better understanding of this entity would help in early diagnosis and aggressive treatment, reducing the overall morbidity and mortality.

A review of paediatric soft tissues masses referred to a tertiary musculoskeletal sarcoma centre

OBJECTIVES

To determine the differential diagnosis of musculoskeletal soft tissue masses in children referred to a specialist musculoskeletal oncology unit.

METHODS

All children (0-18 y) referred to a specialist musculoskeletal oncology unit over a 20-month period (September 2018-May 2020) were retrospectively reviewed. Demographic data and referral diagnoses were obtained from the electronic patient notes. MRI findings and histopathological results were recorded. The comparison of non-neoplastic, benign neoplastic and malignant diagnoses at the point of referral and final diagnosis was determined.

RESULTS

116 patients were included, 60 (51.7%) males and 56 (48.3%) females with mean age of 10.6 years (3 months-18 years). 69 (59.5%) patients were referred with a suspected sarcoma, 29 (25.0%) with a suspected benign tumour and 18 (15.5%) with a non-neoplastic lesion. A diagnosis was achieved by histological assessment in 61 (52.6%) cases, microbiological assessment in 3 (2.6%) or clinical and imaging assessment in 52 (44.8%). 67 (57.8%) cases had non-neoplastic pathology, 39 (33.6%) a benign tumour, 4 (3.4%) an intermediate-grade tumour, 6 (5.2%) a malignant tumour.

CONCLUSIONS

Although over half of children referred to a specialist musculoskeletal oncology unit were suspected of having a soft tissue sarcoma at referral, only 5.2% were diagnosed with a malignant tumour.

ADVANCES IN KNOWLEDGE

Approximately, 6 of 69 (8.7%) children referred to a specialist musculoskeletal oncology unit with a suspected soft tissue sarcoma will have a malignant lesion. Most paediatric soft tissue masses are non-neoplastic, the commonest diagnosis being a vascular malformation.

Pearls and Pitfalls in the Imaging of Soft-Tissue Masses in Children

There is a broad spectrum of soft-tissue masses in children that can be challenging to diagnose clinically and on imaging. This article reviews the typical clinical and imaging findings of the most common and relevant benign, intermediate and malignant pediatric soft-tissue tumors in the following categories of the 2013 World Health Organization (WHO) classification: adipocytic tumors (lipoma, lipoblastoma, and liposarcoma), fibroblastic/myofibroblastic tumors (nodular fasciitis, myositis ossificans, fibrous hamartoma of infancy, fibromatosis colli, desmoid-type fibromatosis, lipofibromatosis, and infantile fibrosarcoma), pericytic tumors (myofibroma/myofibromatosis), skeletal muscle tumor (rhabdomyosarcoma), nerve sheath tumors (neurofibroma, malignant peripheral nerve sheath tumor), and uncertain differentiation (synovial sarcoma). In general, ultrasound and magnetic resonance imaging are used as first- and second-line imaging modalities, with limited roles for plain radiographs, computed tomography, and fluorodeoxyglucose-positron emission tomography. Many of these tumors have nonspecific imaging findings although there are some key imaging clues that in conjunction with the clinical information allow a specific diagnosis or a narrow differential diagnosis. However, in many instances, histology is required for final diagnosis.

[Diagnostic strategy in pediatrics soft tissue sarcomas]

Soft tissue sarcomas in children are rare tumor, representing around 6 to 7% of children cancer. They spread mostly sporadically (90%) and therefore are rarely associated to an underlying constitutional genetic disease (10%). About half of those sarcomas are rhabdomyosarcomas and the others are a very heterogenous histologic group with various bio-pathologies and prognosis. Clinical presentation is mainly a soft tissue lump often difficult to distinguish from more frequent benign causes (malformative, infectious, benign, or pseudotumor). Inappropriate initial diagnosis work-up has a strong impact on soft tissue sarcomas' prognosis. Adapted complementary investigations (first ultrasound and MRI) are important to compile arguments for a malign origin and to indicate a biopsy. However, predictive value of imaging exams still remains imperfect, and histological analysis by percutaneous image-guided biopsy and sometimes by surgical biopsy is often necessary. Authors realize an update on optimal diagnostic pathway including molecular tests in presence of a soft tissue mass in a child.

Diagnostic performance of MRI of post-laminar optic nerve invasion detection in retinoblastoma: A systematic review and meta-analysis

PURPOSE

Preoperative MRI detection of post-laminar optic nerve invasion (PLONI) offers guidance in assessing the probability of total tumor resection, an estimation of the extent of surgery, and screening of candidates for eye-preserving therapies or neoadjuvant chemotherapies in the patients with retinoblastoma (RB). The purpose of this systematic review and meta-analysis was to evaluate the diagnostic performance of MRI for detecting PLONI in patients with RB and to demonstrate the factors that may influence the diagnostic performance.

METHODS

Ovid-MEDLINE and EMBASE databases were searched up to January 11, 2020, for studies identifying the diagnostic performance of MRI for detecting PLONI in patients with RB. The pooled sensitivity and specificity of all studies were calculated followed by meta-regression analysis.

RESULTS

Twelve (1240 patients, 1255 enucleated globes) studies were included. The pooled sensitivity was 61%, and the pooled specificity was 88%. Higgins I² statistic demonstrated moderate heterogeneity in the sensitivity (I² = 72.23%) and specificity (I² = 78.11%). Spearman correlation coefficient indicated the presence of a threshold effect. In the meta-regression, higher magnetic field strength (3 T than 1.5 T), performing fat suppression, and thinner slice thickness (< 3 mm) were factors causing heterogeneity and enhancing diagnostic power across the included studies.

CONCLUSIONS

MR imaging was demonstrated to have acceptable diagnostic performance in detecting PLONI in patients with RB. The variation in the magnetic field strength and protocols was the main factor behind the heterogeneity across the included studies. Therefore, there is room for developing and optimizing the MR protocols for patients with RB.

Advances in image enhancement for sarcoma surgery

The recurrence rate of soft tissue and bone sarcomas strongly correlates to the status of the surgical margin after excision, yet excessive removal of tissue may lead to distinct, otherwise avoidable morbidity. Therefore, adequate margination of sarcomas both pre- and intra-operatively is a clinical necessity that has not yet fully been met. Current guidance for soft-tissue sarcomas recommends an ultrasound scan followed by magnetic resonance imaging (MRI). For bone sarcomas, two plane radiographs are required, followed similarly by an MRI scan. The introduction of more precise imaging modalities may reduce the morbidity associated with sarcoma surgery; the PET-CT and PET-MRI approaches in particular demonstrating high clinical efficacy. Despite advancements in the accuracy in pre-operative imaging, translation of an image to surgical margins is difficult, regularly resulting in wider resection margins than required. For soft tissue sarcomas there is currently no standard technique for image guided resections, while for bone sarcomas fluoroscopy may be used, however margins are not easily discernible during the surgical procedure. Near infra-red (NIR) fluorescence guided surgery offers an intra-operative modality through which complete tumour resection with adequate tumour-free margins may be achieved, while simultaneously minimising surgical morbidity. NIR imaging presents a potentially valuable adjunct to sarcoma surgery. Early reports indicate that it may be able to provide the surgeon with helpful information on anatomy, perfusion, lymphatic drainage, tumour margins and metastases. The use of NIR fluorochromes have also been demonstrated to be well tolerated by patients. However, prior to widespread implementation, studies related to cost-effectiveness and the development of protocols are essential. Nevertheless, NIR imaging may become ubiquitous in the future, carrying the potential to transform the surgical management of sarcoma.

Soft tissue sarcoma in children, adolescents and young adults: Outcomes according to compliance with international initial care guidelines

BACKGROUND

Outcomes for adults with soft tissue sarcoma are better when managed at referral centers. Care guidelines advise for 5 main criteria: 1-Imaging before biopsy; 2-Tumor biopsy before surgery; 3-Multidiscipinary team discussion (MTD) before biopsy; 4-Biopsy in "expert centers"; 5-Somatic molecular biology feasible. The aim is to describe and assess the prognostic impact of initial management of STS according to the type of referring centers and the number of optimal criteria.

METHODS

Monocentric retrospective analysis of the management of 127 youths (0-25 years) with localized STS treated from 2006 to 2015.

RESULTS

Median age at diagnosis was 9.6 years (range: 025). Overall, only 41% patients had 5/5, 28% 3-4, 31% ≤2. No adequate imaging was performed before surgery/biopsy for 18% patients, no biopsy before treatment for 29%. Patients referred by "expert centers" had higher compliance to guidelines (P = 0.025). Upfront surgery was performed in 59/127 patients. Immediate re-operation was inversely related to the number of criteria (0% when 5 criteria vs. 14% for 3-4, 46% if ≤ 2; P < 0.001). For malignant tumors, outcome was better when 5 criteria were reached: 5 year EFS 90.8% (81.4-100.0%) vs. 71.6 for (60.4-84.9%; ≤4 criteria; p = 0.033), OS 93.6% (85.5-100%) vs. 79.5% (68.9-91.8%; p = 0.11), and LRFFS 90.6% (81.0-100.0) vs. 73.1% (62.0-86.3%; p = 0.047).

CONCLUSION

Less than half of the youths with STS are initially managed according to international guidelines, highlighting the need for better information about optimal management. These results plead for immediate management in reference centers to reduce initial burden of therapy.

Synovial sarcoma in the plantar region: A case report and literature review

BACKGROUND

Synovial sarcoma (SS), a rare malignant soft tissue tumor whose histological origin is still unknown, often occurs in limbs in young people and is easily misdiagnosed.

CASE SUMMARY

We report a 24-year-old man who sought treatment for plantar pain thought to be caused by a foot injury that occurred 4 years prior. Currently, he had been seen at another hospital for a 1-wk history of unexplained pain in the left plantar region and was treated with acupuncture, a kind of therapy of Chinese medicine, which partly relieved the pain. Because of this, the final diagnosis of biphasic SS was made after two subsequent treatments by pathological evaluation after the last operation. SS is rarely seen in the plantar area, and his history of a left plantar injury confused the original diagnosis.

CONCLUSION

This study shows that pathological and imaging examinations may play a vital role in the early diagnosis and treatment of SS.

Up-to-date imaging review of paediatric soft tissue vascular masses, focusing on sonography

The purpose of this article is to provide an up-to-date overview on imaging of paediatric vascular soft tissue masses, including both neoplastic and non-neoplastic lesions. We describe the-often challenging-imaging diagnosis-mainly performed by ultrasound (and secondarily by MRI) and differential diagnosis of vascular soft tissue lesions in children. We underline how important it is to determine whether a vascular anomaly has a regional vascular origin, or if there are other entities, ranging from benign to malignant lesions, which have flow-signal or blood degradation products. Even though clinical examination and patient's history are the first and indispensable steps in the initial diagnosis, the role of imaging is crucial, not only to determine whether a mass represents a true tumour/pseudo-tumour, but also to achieve a more correct diagnosis and determine the extension of the tumour/pseudo-tumour and its relation with the nearby anatomic structures.

Spontaneous Regression in a Patient With Infantile Fibrosarcoma

Infantile fibrosarcoma usually presents as a rapidly growing mass on the extremities or trunk. We describe spontaneous regression in a 5-month-old female infant with biopsy proven, molecularly confirmed, right leg infantile fibrosarcoma currently at 26 months of age with no signs of local recurrence. Previously reported cases of spontaneous regression are reviewed, suggesting a benign clinical course in some cases. Although evidence for spontaneous regression is anecdotal in this rare tumor type, physicians should weigh the risks and benefits of surgery and chemotherapy against watchful waiting.

[Imaging characteristics of malignant and benign lesions of skeletal muscle]

There are many different tumors and tumor-like lesions with variable biological behavior that may affect the skeletal musculature. The aim of this study was to review the different intramuscular lesions and to provide a classification based on their radiological patterns. Intramuscular lesions can present as solid, liquid, semiliquid or fat equivalent manifestations and also as diffuse muscle enlargement and muscle calcification. Additionally, lesions with mixed patterns of the aforementioned alterations can also occur. Benign and malignant muscle lesions can often manifest with identical radiological patterns, which is why a certain differentiation is often difficult. A systematic radiological description and when possible assignment with respect to etiology and dignity depending on the patient history is necessary in order to recommend a subsequent histological confirmation or to avoid unnecessary confirmation.

Diagnosis and treatment of soft-tissue sarcomas of the extremities and trunk

The relatively low incidence and often atypical clinical presentation of soft-tissue sarcomas (STS) impedes early and adequate diagnosis. Patients may report on recently enlarged soft-tissue swellings, infrequently complain of painful lesions, or even have no symptoms at all.

A thorough diagnostic work-up is essential in order to distinguish between benign soft-tissue tumours and STSs. Patient history, clinical features and radiological findings all help in assessing the underlying pathology. ‘Worrying’ features such as recent increase in size, deep location relative to the fascia, a tumour exceeding 4 cm in size, and invasive growth patterns seen on imaging should prompt verification by biopsy.

Even though acquisition of biopsy material may be incomplete, one should bear in mind some essential rules. Regardless of the biopsy technique applied, the most direct route to the lump in question should be identified, contamination of adjacent structures should be avoided and a sufficient amount of tissue acquired.

Treatment of STS is best planned by a multidisciplinary team, involving experts from various medical specialities. The benchmark therapy consists of en bloc resection of the tumour, covered by a safety margin of healthy tissue. Depending on tumour histology, grade, local extent and anatomical stage, radiotherapy, chemotherapy and isolated hyperthermic limb perfusion may be employed.

Due to the complexity of treatment, any soft-tissue swelling suspected of malignancy is best referred directly to a sarcoma centre, where therapeutic management is carefully planned by an experienced multidisciplinary team.

Cite this article: EFORT Open Rev 2017;2:421-431. DOI: 10.1302/2058-5241.2.170005

Synovial sarcoma: Magnetic resonance and computed tomography imaging features and differential diagnostic considerations

The present study retrospectively examined 24 cases of pathologically confirmed synovial sarcoma and analyzed the clinical presentation and imaging findings in order to explore the imaging features of synovial sarcoma. The majority of the lesions were large (>5 cm; 88%), rounded or lobulated, relatively well-defined tumor masses in the extremities near the joints or deeply located. On computed tomography (CT) scans, the lesions demonstrated intensity signals similar to those of muscle. Six cases exhibited punctate calcification in the periphery of the tumor. On T1-weighted images, the largest lesions of >5 cm, were usually heterogeneous, with a signal intensity similar to or slightly higher than that of muscle. On T2-weighted images, heterogeneous high-intensity or slightly high-intensity signals were observed, with 12 cases exhibiting a high signal consistent with hemorrhage and 12 presenting signals that indicated internal septations. Contrast-enhanced scanning revealed heterogeneous enhancement in the majority of the lesions and no enhancement in areas of cystic necrosis or internal septations. Synovial sarcoma has specific imaging features, and comprehensive analysis of CT and magnetic resonance imaging can improve the accuracy of the pre-operative diagnosis.

Intramuscular plasmacytoma

OBJECTIVE

In multiple myeloma, secondary infiltration of adjacent muscles from bone lesions is common. However, plasmacytoma directly arising within the skeletal musculature is rare. Imaging findings of this rare entity have been described only sporadically. The purpose of this study was to identify the clinical signs and radiological features of intramuscular plasmacytoma (IP).

MATERIALS AND METHODS

Eleven patients with IP were retrospectively identified in the pathological and radiological databases of our institution. Computed tomography (CT) was performed in nine patients and magnetic resonance imaging (MRI) in four cases.

RESULTS

IP presented clinically with local pain in four patients. In one case with involvement of the rectus lateralis muscle of the eye, the patient showed a painless bulbus proptosis. In another patient, IP manifested as a massive bilateral forearm swelling with compartment syndrome. In four patients, IP was identified incidentally on computed tomography during staging examination. On imaging, two patterns of IP were found: intramuscular mass (n = 5) or diffuse muscle infiltration (n = 6). On CT with contrast, IP showed a moderate enhancement. With MRI on T1-weighted images, IP was isointense in comparison to the unaffected musculature, whereas on T2-weighted images, IP showed high signal intensity. After intravenous administration of contrast medium, a slight-to-moderate inhomogeneous enhancement was seen in all cases.

CONCLUSIONS

IP should be considered in the differential diagnosis of muscle tumors. It manifests with two radiological patterns, either as intramuscular mass or as diffuse muscle infiltration.

Congenital infantile fibrosarcoma: review of imaging features

BACKGROUND

Fibrosarcoma is a rare tumor in children with limited information on imaging features of these tumors in the literature.

OBJECTIVE

To retrospectively review the imaging features of histologically proven congenital infantile fibrosarcoma.

MATERIALS AND METHODS

The list of histologically confirmed congenital infantile fibrosarcomas between November 1999 and June 2013 was obtained from the oncology-pathology database. Imaging features and pathology reports of these tumors were reviewed. Patient charts were reviewed and clinical features, management and outcomes were recorded.

RESULTS

During the study period, 13 children (9 girls and 4 boys; age range: 0 day-16 months, median age: 2.5 months) with congenital infantile fibrosarcomas were available for complete radiological review. The translocation (t[12;15]) was present in 11/13 (84.6%) and absent in 2/13. Eight/thirteen (61.5%) tumors were located in extremities (5 in lower and 3 in upper), 3/13 in thoracolumbar paraspinal regions, and one each in abdomen and sternocleidomastoid muscle. Imaging features included iso- to hyperintensity on T1-W, hyperintensity on T2-W as compared to skeletal muscles and heterogeneous enhancement. Six (37.5%) tumors showed hemorrhagic components and 2 (15.4%) showed low intensity foci. None of the patients had evidence of regional or distant metastases at diagnosis. Management included surgical resection only (1/13) and combined surgery and chemotherapy (10/13). Overall survival was 100% with a median follow-up of 49.3 months.

CONCLUSION

Congenital infantile fibrosarcoma has nonspecific imaging characteristics but should be high on the differential diagnosis in a soft-tissue tumor presenting in infancy, located in an extremity and showing tumoral hemorrhage. Patients have a favorable outcome.

Malignant and benign lesions of the skeletal musculature

There are several tumors and tumorlike conditions with variable biological behavior that may involve the skeletal musculature. The aim of this work was to review different intramuscular lesions and to provide a classification of muscle lesions based on their radiological patterns as well as to provide as a pictorial essay the imaging characteristics of typical muscle lesions. Radiologically, intramuscular lesions can manifest as solid masses, liquid or semiliquid masses, fat-containing lesions, diffuse muscle enlargement, and muscle calcifications. Additionally, lesions with mixed patterns can also occur. It is noteworthy that different malignant or benign muscle lesions can manifest with identical radiological patterns.

Alveolar soft part sarcoma-radiologic patterns in children and adolescents

BACKGROUND

Alveolar soft part sarcoma is a rare but highly malignant tumour and little is known about its radiologic pattern in children.

OBJECTIVE

To describe the radiologic features of alveolar soft part sarcoma in children and adolescents.

MATERIALS AND METHODS

We retrospectively analysed the clinical and imaging data of six children age 7-17 years at diagnosis, with histologically or genetically proven alveolar soft part sarcoma.

RESULTS

The tumours were located deep within muscles of the limbs (n = 4), in chest wall muscle (n = 1) and in the orbit (n = 1). High-flow feeding arteries, large drainage veins and intense enhancement were consistent findings by all imaging modalities. At MRI, all tumours demonstrated high signal intensity on T2-weighted images and high or iso-intense signal on T1-W imaging compared to muscle. In tumours larger than 70 mm in one dimension (n = 3/6), large vessels converging toward the tumour centre led to a highly vascularised central stellar area pattern. Five children demonstrated synchronous (n = 4/5) and metachronous (n = 1/5) lung metastases.

CONCLUSION

Alveolar soft part sarcoma should be suggested when a highly vascularised, intramuscular mass demonstrating large feeding and drainage vessels converging toward a central stellar area is seen in children, especially if synchronous lung metastases are present.