Soft Tissue Sarcoma: Preoperative and Postoperative Imaging for Staging

Malignant Bone and Soft Tissue Lesions of the Foot

Malignant tumors of the foot are rare pathologies that can involve the skin, soft tissue, or bone. Due to their rarity, they are often misdiagnosed, resulting in inadequate excision and poor outcomes. A correct approach with a careful examination and radiological study, followed by a properly performed biopsy, is thus mandatory to avoid these pitfalls. The present article reviews the most common malignant bone and soft tissue lesions of the foot region, discussing their clinicopathological presentation, imaging features, and current concepts in treatment.

CT features of subcutaneous, intermuscular, and intramuscular mast cell tumors in dogs

Surgical removal is the treatment of choice for subcutaneous (SC), intermuscular (InterM), and intramuscular (IntraM) mast cell tumors (MCTs). Advanced imaging (CT or MRI) is frequently used for presurgical planning, but InterM and IntraM MCTs can be difficult to identify and delineate on CT. Aims of the current retrospective, diagnostic accuracy, observer agreement study were to describe the imaging features of SC, InterM, and IntraM MCTs on CT and to assess the limitation of CT to identify the full local extent of the MCT. Inclusion criteria for the study were dogs with a cytologically or histologically diagnosed MCTs determined to be SC, InterM, or IntraM MCT based on histology and/or a CT scan performed in the gross disease setting. Two board-certified veterinary radiologists reviewed the CT images and recorded location, contrast enhancement pattern, and delineation between the normal and abnormal tissue. Sensitivity and specificity of CT for determining location (SC/InterM versus IntraM) was 85.71% and 55.56%, respectively, when compared to consensus location based on surgical pathology report/CT/MRI review. There was a low inter-rater agreement for delineation (kappa: 0.150 (-0.070 to 0.370) and measurement had a low/moderate correlation (rho: 0.4667 to 0.5792). Upon review by a surgical oncologist, CT findings were deemed insufficient for curative surgical planning in 13 of 16 due to inadequate definition of tumor depth, compartment boundary (fascial plane) or MCT margins. The use of CT for presurgical planning of SC/InterM/IntraM MCT dogs has limitations, especially when differentiating MCT from the adjacent muscle.

Personalized Surgical Planning for Soft Tissue Sarcoma of the Popliteal Fossa with a Novel 3D Imaging Technique

OBJECTIVE

Soft tissue sarcomas (STSs) arising from the popliteal fossa pose surgical challenges due to their proximity to critical neurovascular structures. This study aimed to investigate whether a novel 3D imaging technique highlighting these key anatomical structures could facilitate preoperative planning and improve surgical outcomes in STS.

METHODS

This was a prospective, observational, pilot study. Between November 2019 and December 2020, 27 patients with STS of the popliteal fossa undergoing limb-sparing procedures were enrolled and assigned to either a control or intervention group. Control patients underwent traditional preoperative planning with separate computed tomography angiography, magnetic resonance imaging, and magnetic resonance hydrography. In the intervention group, 3D images were generated from these images, the tumor and skeletomuscular and neurovascular structures were revealed in three dimensions, and this was visualized on the surgeon's smartphone or computer. Primary endpoints were surgical margins and complications. Secondary endpoints included operative time, blood loss, serum C-reactive protein and interleukin-6, length of in-hospital stay, and limb function. Comparisons between groups were made using independent-sample t-tests for continuous data and the Mann-Whitney U and Fisher's exact tests for categorical data.

RESULTS

There was a lower but not significantly different inadvertent positive margin rate (1/15 vs. 3/12, P = 0.294), significantly shorter hospital stay (P = 0.049), and less numbers ≥75th percentile of operative time (P = 0.037) and blood loss (P = 0.024) in the intervention group. Differences in surgical complications, operative time, blood loss, C-reactive protein and interleukin-6 levels on the second postoperative day, and limb functional scores were statistically insignificant.

CONCLUSIONS

The novel 3D imaging technique facilitates complex preoperative planning and limb-salvage surgical procedures for patients with STS of the popliteal fossa, and this may affect how surgical planning is performed in the future.

Imaging update on soft tissue sarcoma

Soft tissue sarcomas (STS) are rare tumours presenting as soft tissue lumps. Ultrasound is often the primary modality for the initial assessment, with MRI the mainstay for lesion characterisation. PET/CT along with other emerging MRI sequences are used in certain situations as an adjunct and problem solving tool in STS staging and assessment of disease recurrence. Recent advances include the promise of whole body MRI, hybrid PET/MRI, diffusion weighted imaging, dynamic contrast enhanced MRI and advances in artificial intelligence. This article discusses current concepts in extremity STS imaging and highlights recent advances.

Imaging of Soft Tissue Tumors

Differentiation of malignant from benign soft tissue tumors is challenging with imaging alone, including that by magnetic resonance imaging and computed tomography. However, the accuracy of this differentiation has increased owing to the development of novel imaging technology. Detailed patient history and physical examination remain essential for differentiation between benign and malignant soft tissue tumors. Moreover, measurement only of tumor size based on Response Evaluation Criteria In Solid Tumors criteria is insufficient for the evaluation of response to chemotherapy or radiotherapy. Change in metabolic activity measured by ¹⁸F-fluorodeoxyglucose positron emission tomography or dynamic contrast enhanced-derived quantitative endpoints can more accurately evaluate treatment response compared to change in tumor size. Magnetic resonance imaging can accurately evaluate essential factors in surgical planning such as vascular or bone invasion and "tail sign". Thus, imaging plays a critical role in the diagnosis and treatment of soft tissue tumors.

Diagnostic performance of conventional ultrasound and quantitative and qualitative real-time shear wave elastography in musculoskeletal soft tissue tumors

BACKGROUND

To explore the feasibility to identify malignant musculoskeletal soft tissue tumors using real-time shear wave elastography (rtSWE).

METHODS

One hundred fifteen musculoskeletal soft tissue tumors in 92 consecutive patients were examined using both conventional ultrasonography (US) and rtSWE. For each patient, the rtSWE parameters including maximum elasticity (E_max), mean elasticity (E_mean), minimum elasticity (E_min), standard deviation of the elasticity (E_sd), and rtSWE image pattern were obtained. Eighty-one histopathologically confirmed tumors from 73 patients were subjected to analysis.

RESULTS

The 81 lesions included in the study were histopathologically classified as malignant (n = 21) or benign (n = 60). The statistically significant differences between benign and malignant lesions were found in conventional US characters including size, depth, margin, echogenicity, mass texture, and power Doppler signal. Meanwhile, the significant differences were also found in quantitative rtSWE findings including E_max, E_mean, E_min, and E_sd values and in qualitative rtSWE parameter named rtSWE image pattern. Multivariate analysis showed that infiltrative margin (OR, 4.470), and size (OR, 1.046) were independent predictors for malignancy in US findings, while E_sd value (OR, 9.047) was independent predictors for malignancy in quantitative rtSWE parameters. Areas under the ROC curve (Azs) for US features, E_sd value, and rtSWE image pattern were 0.851, 0.795, and 0.792, respectively.

CONCLUSIONS

Conventional US and quantitative and qualitative rtSWE parameters are useful for malignancy prediction of musculoskeletal soft tissue tumors. rtSWE can be used to supplement conventional US to diagnose musculoskeletal soft tissue tumors.

Primary appendicular soft-tissue sarcoma resection: What tumour parameters affect wound closure planning?

Wound closure after wide, local excision of an appendicular soft-tissue sarcoma (STS) can be challenging. This study evaluates the value of magnetic resonance imaging (MRI)-based tumour parameters in planning wound closure. A total of 71 patients with a primary limb-based STS, excluding vascular or osseous involvement, excluding the shoulder or hand and hip or foot were included. Axial MRI images were used to measure the circumferences and cross-sectional areas of the limb, bone, and tumour. The tumour diameter, length, and depth at the level of maximal tumour dimension were measured to identify the tumour's relative contribution to the planning of optimal wound closure management through primary closure (PC) or reconstructive surgery (RS). Eighteen patients required planned wound RS. Wound complications occurred in 14% overall. Tumours, which were closed by PC, were of significantly greater depth, shorter radial diameter, and shorter tumour circumference relative to those closed by RS. On multivariate analysis, tumour depth was the greatest contributory factor in predicting type of wound closure. A quantitative analysis of MRI-based tumour parameters demonstrates tumour depth as the most predictive factor in planning for the type of wound closure and may prove beneficial in providing greater insight into planned wound management of sarcoma resection.

Value of the Cinematic Rendering From Volumetric Computed Tomography Data in Evaluating the Relationship Between Deep Soft Tissue Sarcomas of the Extremities and Adjacent Major Vessels: A Preliminary Study

Supplemental digital content is available in the text.

Objective

The aim of the study was to assess the value of cinematic rendering (CR) from volumetric computed tomography data in evaluating the relationship between deep soft tissue sarcomas (STSs) of the extremities and the adjacent major vessels.

Methods

Preoperative contrast-enhanced axial imaging (CEAI) in the arterial phase with three-dimensional volume rendering (VR) and CR of contrast-enhanced computed tomography were used to assess adjacent vascular invasion in 43 cases of deep STSs of the extremities. The imaging assessments were compared with surgical findings and interpreted as negative (no vascular invasion) or positive (vascular invasion was present). Intrareader and interreader agreement were assessed using Cohen κ statistics. The diagnostic performance of CEAI, VR, and CR was evaluated by receiver operating curve analysis and compared using the DeLong test.

Results

Thirty-four and nine cases were classified as negative and positive, respectively, in surgery. Intrareader agreement values for the CEAI, VR, and CR assessments were all excellent (0.984, 0.934, and 0.914, respectively), whereas the interreader agreement for CEAI assessments was greater than that for VR and CR (0.969 vs 0.804 and 0.761). Cinematic rendering showed lower accuracy (0.698), sensitivity (0.778), specificity (0.676), positive predictive values (0.389), and negative predictive values (0.920) for vascular invasion diagnosis than CEAI or VR; the accuracy, sensitivity, specificity, positive predictive values, and negative predictive values increased to 0.767, 0.889, 0.735, 0.471, and 0.962 for both CEAI and VR. The results were not statistically significant (all P > 0.05).

Conclusions

Cinematic rendering has the potential to be used to evaluate vascular invasion in cases of deep STSs of the extremities, but it should be used alongside the traditional methods such as CEAI.

Retrospective audit of 957 consecutive 18F-FDG PET-CT scans compared to CT and MRI in 493 patients with different histological subtypes of bone and soft tissue sarcoma

Background

The use of ¹⁸F-FDG PET–CT (PET–CT) is widespread in many cancer types compared to sarcoma. We report a large retrospective audit of PET–CT in bone and soft tissue sarcoma with varied grade in a single multi-disciplinary centre. We also sought to answer three questions. Firstly, the correlation between sarcoma sub-type and grade with ¹⁸FDG SUVmax, secondly, the practical uses of PET–CT in the clinical setting of staging (during initial diagnosis), restaging (new baseline prior to definitive intervention) and treatment response. Finally, we also attempted to evaluate the potential additional benefit of PET–CT over concurrent conventional CT and MRI.

Methods

A total of 957 consecutive PET–CT scans were performed in a single supra-regional centre in 493 sarcoma patients (excluding GIST) between 2007 and 2014. We compared, PET–CT SUVmax values in relation to histology and FNCCC grading. We compared PET–CT findings relative to concurrent conventional imaging (MRI and CT) in staging, restaging and treatment responses.

Results

High-grade (II/III) bone and soft tissue sarcoma correlated with high SUVmax, especially undifferentiated pleomorphic sarcoma, leiomyosarcoma, translocation induced sarcomas (Ewing, synovial, alveolar rhabdomyosarcoma), de-differentiated liposarcoma and osteosarcoma. Lower SUVmax values were observed in sarcomas of low histological grade (grade I), and in rare subtypes of intermediate grade soft tissue sarcoma (e.g. alveolar soft part sarcoma and solitary fibrous tumour). SUVmax variation was noted in malignant peripheral nerve sheath tumours, compared to the histologically benign plexiform neurofibroma, whereas PET–CT could clearly differentiate low from high-grade chondrosarcoma. We identified added utility of PET–CT in addition to MRI and CT in high-grade sarcoma of bone and soft tissues. An estimated 21% overall potential benefit was observed for PET–CT over CT/MRI, and in particular, in ‘upstaging’ of high-grade disease (from M0 to M1) where an additional 12% of cases were deemed M1 following PET–CT.

Conclusions

PET–CT in high-grade bone and soft tissue sarcoma can add significant benefit to routine CT/MRI staging. Further prospective and multi-centre evaluation of PET–CT is warranted to determine the actual predictive value and cost-effectiveness of PET–CT in directing clinical management of clinically complex and heterogeneous high-grade sarcomas.

Evaluating Soft-Tissue Lumps and Bumps

Patients presenting with soft-tissue lumps and bumps are commonly encountered by both primary care physicians and orthopaedic surgeons. Though common, the initial evaluation and management of a soft-tissue mass can be challenging for many clinicians due to the considerable overlap in the presentation of benign and malignant tumors. Furthermore, a myriad of conditions, ranging from infection to trauma, can present with a soft-tissue mass. Subsequently, the correct diagnosis is often delayed or missed which may ultimately lead to inappropriate treatment. The propose of this article is to review the fundamental elements of a successful soft-tissue mass work-up and to provide the clinician with a systematic approach to the evaluation, diagnosis and management of the patient with a soft-tissue tumor.

Management of Recurrent Retroperitoneal Sarcoma (RPS) in the Adult: A Consensus Approach from the Trans-Atlantic RPS Working Group

INTRODUCTION

Retroperitoneal soft tissue sarcomas (RPS) are rare tumors. Surgery is the mainstay of curative therapy, but local recurrence is common. No recommendations concerning the best management of recurring disease have been developed so far. Although every effort should be made to optimize the initial approach, recommendations to treat recurring RPS will be helpful to maximize disease control at recurrence.

METHODS

An RPS transatlantic working group was established in 2013. The goals of the group were to share institutional experiences, build large multi-institutional case series, and develop consensus documents on the approach to this difficult disease. The outcome of this document applies to recurrent RPS that is nonvisceral in origin. Included are sarcomas of major veins, undifferentiated pleomorphic sarcoma of psoas, ureteric leiomyosarcoma (LMS). Excluded are desmoids-type fibromatosis, angiomyolipoma, gastrointestinal stromal tumors, sarcomas arising from the gut or its mesentery, uterine LMS, prostatic sarcoma, paratesticular/spermatic cord sarcoma, Ewing sarcoma, alveolar/embryonal rhabdomyosarcoma, sarcoma arising from teratoma, carcinosarcoma, sarcomatoid carcinoma, clear cell sarcoma, radiation-induced sarcoma, paraganglioma, and malignant pheochromocytoma.

RESULTS

Recurrent RPS management was evaluated from diagnosis to follow-up. It is a rare and complex malignancy that is best managed by an experienced multidisciplinary team in a specialized referral center. The best chance of cure is at the time of primary presentation, but some patients may experience prolonged disease control also at recurrence, when the approach is optimized and follows the recommendations contained herein.

CONCLUSIONS

International collaboration is critical for adding to the present knowledge. A transatlantic prospective registry has been established.

Accuracy and role of contrast-enhanced CT in diagnosis and surgical planning in 88 soft tissue tumours of extremities

OBJECTIVES

Soft tissue tumours (STT) require accurate diagnosis in order to identify potential malignancies. Preoperative planning is fundamental to avoid inadequate treatments. The role of contrast-enhanced computed tomography (CT) for local staging remains incompletely assessed. Aims of the study were to evaluate CT accuracy in discriminating active from aggressive tumours compared to histology and evaluate the role of CT angiography (CTA) in surgical planning.

MATERIALS AND METHODS

This retrospective cohort series of 88 cases from 1200 patients (7 %) was locally studied by contrast-enhanced CT and CTA in a referral centre: 74 malignant tumours, 14 benign lesions. Contrast-enhancement patterns and relationship of the mass with major vessels and bone were compared with histology on surgically excised samples. Sensitivity, specificity, positive and negative predictive values (PPV, NPV) were evaluated in discriminating active from aggressive tumours.

RESULTS

Sensitivity in differentiating aggressive tumours from active lesions was 89 %, specificity 84 %, PPV 90 %, NPV 82 %. The relationship between mass and major vessels/bone was fundamental for surgical strategy respectively in 40 % and in 58 % of malignant tumours.

CONCLUSION

Contrast-enhanced CT and CTA are effective in differentiating aggressive masses from active lesions in soft tissue and in depicting the relationship between tumour and adjacent bones and major vessels.

KEY POINTS

• Accurate delineation of vascular and bony involvement preoperatively is fundamental for a correct resection. • CT plays a critical role in differential diagnosis of soft tissue masses. • Contrast-enhanced CT and CT angiography are helpful in depicting tumoral vascular involvement. • CT is optimal for characterization of bone involvement in soft tissue malignancies.

Surgical management of retroperitoneal and pelvic sarcomas

Management of retroperitoneal sarcomas presents technical and oncological challenges. Imaging is crucial for diagnosis and to define local tumor extent. Complete gross resection at initial presentation is the best chance for cure, but there is controversy as to how this can be best achieved. There is a long-term risk of local recurrence, which is best treated with repeat resection if feasible. The roles of radiation and chemotherapy remain undefined.

Diagnosis and Management of Soft-tissue Masses

Soft-tissue masses of the extremities are common entities encountered by nearly all providers of musculoskeletal patient care. Proper management of these lesions requires a specific process of evaluation. A detailed history and physical examination must be performed. Appropriate imaging studies must be obtained based on clinical indications. MRI is the imaging modality of choice for diagnosis of soft-tissue masses, with CT and ultrasonography used as secondary options. These modalities aid the clinician in developing an appropriate differential diagnosis and treatment plan. When the initial evaluation is inconclusive, biopsy must be performed. A diagnosis must be established before definitive treatment with surgical excision or, in rare cases, radiation therapy is performed. Clinicians without significant experience in treating soft-tissue masses should consider referral to a musculoskeletal oncologist for specialized care when a definitive diagnosis of a benign lesion cannot be made. Several studies have shown that multidisciplinary care in specialized referral centers optimizes outcomes and diminishes comorbid complications.

A guide to oncological management of soft tissue tumours of the abdominal wall

INTRODUCTION

An abdominal mass is a common clinical presentation, and a small percentage of such patients will have an abdominal wall tumour with the two most common pathologies being fibromatosis and soft tissue sarcoma.

METHODS

Here we present the available literature on the diagnosis and management of both fibromatosis and soft tissue sarcoma, in the context of our experience in a tertiary referral centre for sarcoma.

RESULTS AND DISCUSSION

Appropriate cross-sectional imaging and a pre-operative tissue diagnosis by percutaneous core biopsy are necessary to define management. Desmoid fibromatosis can be managed initially by observation with serial imaging, with surgery being reserved for those patients who demonstrate progression. Soft tissue sarcoma can display a range of pathologies from relatively indolent tumours to locally aggressive sarcomas that can readily metastasise. An accurate pre-operative histological diagnosis and staging enables a multidisciplinary approach to management. This may include chemotherapy and radiotherapy, but the mainstay of treatment remains wide surgical resection and abdominal wall reconstruction. Patient outcomes are worse if referral is delayed or if the sarcoma is incompletely resected without an initial tissue diagnosis.

Retroperitoneal sarcomas- a challenging problem

Retroperitoneal sarcomas are relatively rare tumours and usually present in a locally advanced stage. Liposarcoma is the most common histopathology. If operable, surgery is the treatment of choice. The role of adjuvant chemotherapy or radiotherapy is not yet defined. Advanced cases are treated by chemotherapy. The prognosis is poor in patients with positive resection margins, high-grade tumours and recurrent tumours.

Reliability of Margin Assessment after Surgery for Extremity Soft Tissue Sarcoma: The SSG Experience

Surgery remains the mainstay of soft tissue sarcoma (STS) treatment and has been the primary treatment for the majority of patients in Scandinavia during the last 30 years although the use of adjuvant radiotherapy has increased. Patient and treatment characteristics have been recorded in the Scandinavian Sarcoma Group (SSG) Register since 1987. When the effect of new radiotherapy guidelines from 1998 was evaluated, the reliability of surgical margin assessments among different Scandinavian institutions was investigated. Margins were reevaluated by a panel of sarcoma surgeons, studying pathology and surgical reports from 117 patients, randomly selected among 470 recorded patients treated between 1998–2003. In 80% of cases, the panel agreed with the original classification. Disagreement was most frequent when addressing the distinction between marginal and wide margins. Considered the element of judgment inherent in all margin assessment, we find this reliability acceptable for using the Register for studies of local control of STS.

Prognostic factors and staging for soft tissue sarcomas: an update

Soft tissue sarcoma (STS) staging is a constantly evolving process. Grading is still of utmost importance and has been adapted into a three-tier system. The STS most difficult to categorize are those with uncertain malignant potential, such as solitary fibrous tumors, gastrointestinal stromal tumors, and glomus tumors, some of which have developed completely separate staging systems and may not even be considered sarcomas. Beyond the current TNM staging system, a multitude of prognostic factors for STS will continue to be discovered and ultimately incorporated into future revisions of the staging system.

Multimodality treatment of locally advanced soft-tissue sarcomas of the extremities

BACKGROUND

Adjuvant radiotherapy (RTE) still has a fundamental role as a post-operative treatment of locally advanced soft tissues sarcomas of the extremities. Moreover the employment of combined modalities in locally advanced soft tissues sarcomas of the extremities allow to maximize the chance of local cure even in difficult presentation cases, and possibly improve survival, especially in high-risk disease patients. In patients with sarcomas of the extremities in which definitive surgery has not been radical (with positive or "close" margins) radiotherapy can improve the results in terms of Disease Free Survival (DFS) and, together with chemotherapy, of Overall Survival (OS). We recommend radiotherapy in case of deep tumor location, inadequate surgical margins and grade 3 tumour; for positive or "marginal (or close)" excision (that means inadequate surgery) or in selected patients with a bad prognosis, we believe that a multidisciplinary approach can be preferable.

INTRODUCTION

Adjuvant radiotherapy (RTE) still has a fundamental role as a post-operative treatment. In patients with sarcomas of the extremities in whom definitive surgery has been or not radical (positive or "close" margins), radiotherapy with chemotherapy can improve the results in terms of Disease Free Survival (DFS) and Overall Survival (OS), while RTE alone seems to improve local control.

MATERIALS AND METHODS

From 1/2000 to 12/2005 we treated 34 patients affected by locally advanced sarcomas of the upper or lower extremities with radiotherapy (doses ranging from 54 to 66 Gy) and chemotherapy in 18/34 with an adjuvant scheme that consisted in Epirubicine (120 mg/m(2)) plus Ifosfamide (7000-9000 mg/m(2)).

RESULTS

Disease Free Survival (DFS) and the Overall Survival (OS) rates were 76% and 82%, respectively. Eighteen patients developed one or more long-term side effects. Most of these complications were mild: all patients experienced only erithema, edema, local sclerosis or moderate pain.

CONCLUSION

Radiotherapy has an important role as a post-operative treatment also when surgery was non-radical. It improves local control more in patients with high-grade sarcomas of the extremity with positive or close margins. It is still difficult to assess the role of adjuvant chemotherapy.

[Surgical therapy of abdominal and trunk soft tissue sarcomas]

Soft tissue sarcomas are rare tumours of mesenchymal cells which can arise in all parts of the body. Sarcomas of the trunk and abdominal cavity are a very heterogeneous group of tumours. This review focuses on retroperitoneal sarcomas, which tend to be asymptomatic for a long time, resulting in an advanced stage at presentation in most patients. Surgical resection is the basis for cure in these patients, possibly combined with radiation. In contrast to extremity sarcomas, the majority of patients with retroperitoneal sarcomas succumb to an isolated local recurrence of the disease. In case of local recurrence or distant metastases, surgical resection should again be contemplated.

The management of soft tissue sarcoma

SUMMARY

Soft tissue sarcomas are a rare group of mesenchymal tumours that display cardinal signs, which can raise suspicion to their diagnosis. Management in a sarcoma treatment centre by its multidisciplinary team has improved outcome. Good local disease control with limb salvage and adjuvant radiotherapy has considerably reduced the morbidity of previous limb amputation. By the early involvement of a plastic surgeon, tissue reconstruction is optimised and wound complications reduced. This article looks at the contemporary management of soft tissue sarcoma and, in particular, its relevance to the plastic surgeon today.