Imaging in Sarcoma

68 Ga-FAPI-04 Versus 18 F-FDG PET/CT in Duodenal Synovial Sarcoma

ABSTRACT

A previously healthy 18-year-old man with a 9-month history of upper abdominal pain and significant weight loss underwent gastroscopy, revealing an ulcerative lesion in the duodenal bulb. Enrolled in a clinical trial, both 18 F-FDG and 68 Ga-FAPI-04 PET/CT demonstrated similar metabolic activity, though 68 Ga-FAPI-04 offered superior lesion delineation. Pathology confirmed synovial sarcoma. This case highlights the potential utility of 68 Ga-FAPI-04 as a radiopharmaceutical for evaluating rare gastrointestinal synovial sarcomas.

Paradoxical action of PP2A inhibition and its potential for therapeutic sensitization

The protein phosphatase 2A (PP2A), a serine/threonine phosphatase, is recognized as a tumor suppressor involved in diverse cellular processes and essential for maintaining cell viability in vivo. However, endogenous inhibitors of PP2A such as cancerous inhibitor of PP2A (CIP2A) and endogenous nuclear protein inhibitor 2 of PP2A (SET) counteract the anticancer function of PP2A, promoting tumorigenesis, development, and drug resistance in tumors. Surprisingly though, contrary to conventional understanding, inhibition of the tumor suppressor gene PP2A with exogenous small molecule compounds can enhance the efficacy of cancer treatment and achieve superior tumor inhibition. Moreover, exogenous PP2A inhibitors resensitize cancers to treatment and provide novel therapeutic strategies for drug-resistant tumors, which warrant further investigation.

Association of SMC4 with prognosis and immune infiltration of sarcoma

OBJECTIVE

This study was performed to explore the prognostic relevance of structural maintenance of chromosomes 4 (SMC4) in pan-cancer and explore the association between SMC4 and immune infiltration of sarcoma.

RESULTS

Elevated expression of SMC4 was detected in cancer tissues compared to normal tissue, which was confirmed in synovial sarcoma tissues with immunohistochemistry (IHC). Additionally, higher expression of SMC4 was connected to worse outcomes of sarcoma, gastric cancer, breast cancer, liver cancer or ovarian cancer. Moreover, SMC4 was positively connected to immune cell infiltrates in sarcoma. In addition, infiltrating immune cell markers including monocyte, TAM, M1 and M2 presented different SMC4-associated immune infiltration patterns.

CONCLUSION

The results from our study showed that SMC4 was positively related to the prognosis and immunological status of sarcoma. SMC4 could be a potential biomarker for prognosis and immune cell infiltrates in sarcoma.

METHODS

Several databases including ONCOMINE, GEPIA, and Kaplan-Meier Plotter were adopted to explore the expression pattern of SMC4 in sarcoma, which was confirmed by IHC. The GEPIA and TIMER datasets were adopted to investigate the associations between SMC4 and prognosis in various cancers, especially in sarcoma.

Prognostic usefulness of clinical features and pretreatment 18F-FDG PET/CT metabolic parameters in patients with angiosarcoma

BACKGROUND

To investigate the prognostic value of clinical features and metabolic parameters in pretreatment 18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/X-ray computed tomography (PET/CT) scans of patients with angiosarcoma, a rare neoplasm that has not been well characterized.

METHODS

In this retrospective study, 19 patients with a histopathologically confirmed diagnosis of angiosarcoma who had undergone pretreatment 18F-FDG PET/CT scans were enrolled. We recorded the age at presentation, sex, underlying diseases, sites of primary tumors, Karnofsky Performance Status (KPS) score, Eastern Cooperative Oncology Group (ECOG) score, time from onset to diagnosis, laboratory examinations, sites and sizes of primary tumors, treatment modalities, histologic features and American Joint Committee on Cancer (AJCC) stage, maximum standardized uptake value (SUVmax), average SUV (SUVavg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of primary tumors and the whole body. Univariate and multivariate survival analyses for overall survival were performed according to the metabolic parameters and other clinical variables.

RESULTS

Patients ranged in age from 27 to 79 years (median: 59 years) with different angiosarcoma types covering all tumor grades and subtypes. Seven (7/19) patients had anemia of varying degrees of severity. Lymph node metastases (n=10) and/or distant metastases (n=11) of angiosarcoma were common. Bone or bone marrow (10/19) and lung (8/19) were the most common distant metastatic organs. Patients with bone metastases, low hemoglobin levels and high ferritin levels had significantly poorer overall survival than those with non-bone metastases, normal hemoglobin levels and normal ferritin levels by the log-rank test, with P values of 0.027, 0.030 and 0.015, respectively. Patients with multiple organ metastases had significantly poorer overall survival than those with single organ metastasis (log-rank P=0.008). In multivariate survival analysis, only whole-body metabolic tumor volume using SUVmax cut-off value of 2.5 (wMTV2.5) was a significant independent prognostic factor. For wMTV2.5, 870.3 cm3 was the best cut-off point to discriminate between a good and poor prognosis (log-rank P=0.01).

CONCLUSIONS

The systemic 18F-FDG PET/CT with high sensitivity and specificity has significant advantages in the evaluation of angiosarcoma, particularly in detecting occult metastases. Bone metastases on 18F-FDG PET/CT, low hemoglobin levels and high ferritin levels were all associated with a poorer prognosis. MTV2.5 of the whole body is a significant independent metabolic prognostic factor for overall survival in patients with angiosarcoma.

Malignant primary intraosseus synovial sarcoma – a rare case report

Primary intraosseous synovial sarcoma is an extremely rare malignancy that occurs primarily in young adults. We present a case of a primary intraosseous synovial sarcoma of the right distal ulna in a 19-year-old female. It has a propensity to mimic other radiologic and pathologic diagnosis. Histopathology after a surgical excisional biopsy with a wide margin plus adjunct radio and chemotherapy are necessary to improve prognosis.

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.

The Utility of 18FDG PET/CT Versus Bone Scan for Identification of Bone Metastases in a Pediatric Sarcoma Population and a Review of the Literature

BACKGROUND

Outcome of patients with osteosarcoma (OS) and Ewing sarcoma (EWS) is dependent on presence of metastases. Imaging guidelines for OS and EWS include radiographs, computed tomography (CT), and magnetic resonance imaging for primary tumor evaluation and CT chest and bone scintigraphy (BS) for metastatic detection. 18Fluorodeoxyglucose (18FDG) positron emission tomography (PET)/CT has become more common for disease evaluation, yet there is no consensus for its use in this population.

OBJECTIVE

We aimed to compare identification of osseous metastases using BS versus 18FDG PET/CT in our patient population. We hypothesized that 18FDG PET/CT is more likely to detect osseous metastases both at diagnosis and relapse.

MATERIALS AND METHODS

We performed retrospective chart reviews of pediatric sarcoma patients treated at our institution from 2008 to 2019. Paired BS and 18FDG PET/CT scans were reviewed. Review of the literature was also performed.

RESULTS

Thirty-three patients had paired BS and 18FDG PET/CT during diagnosis or treatment. Fifteen patients had distant osseous metastases. In the OS cohort, 8/16 patients had osseous metastases; 100% of these patients were detected on 18FDG PET/CT and 75% on BS. Thirty-one bony lesions were seen on imaging in OS patients; 100% of these were identified on 18FDG PET/CT but only 29% on BS. In the EWS cohort, 6/15 patients had osseous metastases; 100% of these patients were detected on 18FDG PET/CT and 50% on BS. Eighteen bony lesions were seen on imaging in EWS patients; 94% of these were identified on 18FDG PET/CT, but only 28% on BS.

CONCLUSION

For patients in our institution with OS or EWS, osseous metastases were more likely detected using 18FDG PET/CT.

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.

PET in the Diagnostic Management of Soft Tissue Sarcomas of Musculoskeletal Origin

Soft tissue sarcomas (STSs) account for less than 1% of adult solid tumors and about 7% of pediatric malignancies, causing 2% of cancer-related deaths. With the advent of PET-computed tomography (CT), the value of (18) fluorine-2-fluoro-2-deoxy-d-glucose (FDG) PET imaging to improve the management of STSs has been explored. FDG PET imaging has been found useful in restaging and treatment response assessment. This article reviews current knowledge and application of FDG PET-CT in initial diagnosis, staging, restaging, treatment response monitoring, and prognosis, with a brief overview of the most common histologic subtypes of STS.

Indium-111 labeled leukocyte accumulation in extremity soft tissue sarcoma

Nuclear medicine labeled leukocyte whole-body scintigraphy is commonly used to identify a source of infection in a patient with fever of unknown origin. White blood cells can also localize to other sites of inflammation, including sometimes tumors. A patient with a large myxofibrosarcoma in his left forearm was scanned due to chronic low-grade fever and persistent leukocytosis. This case demonstrates focal white blood cell activity in an extremity soft tissue sarcoma.

The Possible Role of PET Imaging Toward Individualized Management of Bone and Soft Tissue Malignancies

This article presents fluorodeoxyglucose PET/computed tomography for the evaluation of soft tissue sarcomas. Its clinical impact is discussed analyzing all the clinical information provided when applied in different phases of the disease. A special paragraph is dedicated to the use of functional imaging for driving the biopsy.

Is PET-CT an accurate method for the differential diagnosis between chondroma and chondrosarcoma?

The differential diagnosis between chondroma and intraosseous chondrosarcoma is based on imaging and clinical exams, but only a biopsy can confirm diagnosis. The aim of this study was to evaluate the value of PET–CT in differentially diagnosing chondroma and chondrosarcoma. From October 2009 to May 2015, 36 patients with cartilaginous bone lesions in the extremities, 12 (33.3 %) men and 24 (66.6 %) women, were prospectively included in the study. Patients ranged in age from 21 to 68 years, with a mean age of 44 years. Lesions were located in the long bones: in the proximal humerus in 26 (72.2 %) patients, in the femoral shaft in 1 (2.7 %), in the distal femur in 7 (19.4 %), and in the proximal tibia in 2 (5.5 %). The SUVmax value of 2.0 was used to separate between patients submitted to surgery and patients submitted to observation. Among the 36 patients studied, 17 (47.2 %) had SUVmax ≤ 2.0, and they were diagnosed as chondroma and they were treated conservatively. Follow-up ranged from 14 to 76 months, averaging 38 months. Nineteen (52.7 %) patients with SUVmax >2.0 were diagnosed as chondrosarcoma and underwent surgery. The area of the curve, calculated considering the SUV variable as numeric, is estimated in 0.966, with a 95 % confidence interval from 0.906 to 1.000. To evaluate the sensitivity, specificity and positive/negative predictive values, it was built a 2 × 2 table. Significance was set at p < 0.05. According the criteria of maximum sensitivity and specificity, the cut point suggested to SUVmax was 2.2. If we consider this point, it is possible to identify 19 of 36 positive cases to chondroma (52.8 %), it means, all chondrosarcomas of the series. We concluded that PET–CT can be used as an objective and quantitative method of differentiating between chondromas and chondrosarcomas located within the long bones. It represents a complementary examination to standard imaging (X-ray, scintigraphy, CT and MRI) and pathological exams. The SUVmax between 2.0 and 2.2 would be a range area between chondroma and chondrosarcoma and this range can be of value, among others exams, in decide the best treatment for patients with cartilaginous lesions in long bones.

Level of evidence Level I—diagnostic study—prospectively investigating a diagnostic test using a universally applied “gold” standard.

Surgical management and minimally invasive approaches for the treatment of metastatic sarcoma

Soft tissue sarcomas describe a very heterogeneous group of soft tissue tumors mainly arising in the lower extremities. If diagnosed at an early stage and a complete resection of the primary tumor is achieved, the patients' prognosis is excellent. However, metastatic tumor spread is common with only limited treatment possibilities. Despite an improved insight into tumor biology of sarcomas, no notable improvement has been gained in the last 20 years regarding prognosis of patients. Metastatic lung disease has long been the preserve of systemic treatments, local treatments being considered in a purely palliative intention. Several studies have objectified benefit to the local treatment of metastases, especially in an oligometastatic state. The development of techniques for stereotactic radiotherapy on the one hand and the refusal or contraindication for surgery on the other hand inaugurated studies in this direction. Besides surgery and radiotherapy, other local modalities have been investigated in the last few years such as thermal therapy (radiofrequency and laser ablation) or combined modalities (isolated limb perfusion and deep-wave hyperthermia plus chemotherapy) to help patients with metastatic soft tissue sarcoma. Minimally invasive, image-guided therapies such as thermal ablation should be considered particularly in patients who are not suitable surgical candidates or may have exhausted all other viable surgical options. Some of these techniques will be reviewed in this article, and their value for the patients will be evaluated in the light of indication from tumor biology and technical feasibility. These highly selected and specific procedures should only be performed after decision making in an interdisciplinary sarcoma-board.

Spectrum of Physiologic and Pathologic Skeletal Muscle (18)F-FDG Uptake on PET/CT

OBJECTIVE

Skeletal muscle (18)F-FDG uptake on PET/CT can be either physiologic or related to a variety of different pathologic conditions. FDG PET/CT can be used for assessment of primary and metastatic tumors and infective or inflammatory conditions affecting the musculature.

CONCLUSION

In this article, we describe the various causes and patterns of skeletal muscle FDG uptake. Familiarity with these patterns is essential for proper interpretation of clinical FDG PET/CT images.

Impact of (18)F-FDG PET/CT imaging in therapeutic decisions for malignant solitary fibrous tumor of the pelvis

The decision to give neoadjuvant chemotherapy in patients with localized high-risk soft tissue sarcoma is often based on tumor grade evaluated from biopsies, but biopsies can have the inherent issue of sampling bias. Incorporation of SUVmax and heterogeneity assessed by F-FDG PET/CT could be other crucial components in the effort to tailor treatment to an individual patient, providing valuable parameters to guide the selection of the most appropriate management schedule for an individual. We present 1 representative case describing how FDG PET/CT can assist in clinical management decisions for treatment of malignant solitary fibrous tumor of the pelvis.

(18) F-fluorodeoxyglucose positron emission tomography/computed tomography for the detection of recurrent bone and soft tissue sarcoma

BACKGROUND

The clinical utility of modern hybrid imaging modalities for detecting recurrent bone or soft tissue sarcoma remains to be determined. In this report, the authors present a clinical study on the diagnostic accuracy and incremental value of integrated (18) F-fluorodeoxyglucose positron emission tomography/computed tomography ((18) F-FDG PET/CT) in patients with a history of sarcoma who have clinically suspected disease recurrence.

METHODS

Forty-three patients who had a history of bone or soft tissue sarcoma and had documented complete remission underwent (18) F-FDG PET/CT. Image analysis was performed independently for (18) F-FDG PET (n = 43) and for contrast-enhanced spiral CT (CE-CT) (n = 30) by 2 separate readers, whereas combined (18) F-FDG PET/CT (n = 43) images were analyzed in consensus by both readers. Imaging findings were rated on a 5-point scale and finally were reported as malignant, benign, or equivocal. Imaging findings were validated either by histopathology (n = 24) or by clinical follow-up (n = 19).

RESULTS

(18) F-FDG PET/CT had greater sensitivity and specificity compared with CE-CT alone (94% and 92% vs 78% and 67%, respectively), resulting in significantly greater accuracy (93% vs 73%; P = .03). (18) F-FDG PET/CT was particularly superior regarding detection of local recurrence or soft tissue lesions (sensitivity and specificity: 83% and 100% vs 50% and 100%, respectively) or bone metastases (100% and 100% vs 85% and 88%, respectively).

CONCLUSIONS

(18) F-FDG PET/CT had greater diagnostic accuracy in the detection of recurrent bone or soft tissue sarcoma compared with CE-CT alone. The detection of local recurrence was the most evident advantage of (18) F-FDG PET/CT over CE-CT. Cancer 2013. © 2012 American Cancer Society.

Synovial sarcoma: imaging features of common and uncommon primary sites, metastatic patterns, and treatment response

OBJECTIVE

The purpose of this review is to describe the imaging features, common and uncommon sites, metastatic pattern, and treatment response of synovial sarcoma.

CONCLUSION

Synovial sarcoma primarily occurs in young adults, most commonly in the lower extremities; presents as a large, noninfiltrative, well-circumscribed mass adjacent to joints, often with punctuate calcifications; and may exhibit a triple signal pattern on T2-weighted images. Small synovial sarcomas can mimic benign lesions. This tumor has a propensity for late local recurrence and metastasis, most commonly to lung.

[Positron emission tomography-computed tomography in tumors of the locomotor apparatus]

Positron emission tomography/computed tomography (PET/CT) is a hybrid imaging technique that combines the anatomic information from CT with the metabolic information acquired from PET after the administration of specific radiotracers, the most commonly used of which is F18-fluorodeoxyglucose (FDG). In oncology, this technique is based on the increased uptake of FDG by malignant lesions. In the locomotor apparatus, some uptake by bones and soft tissues is physiological or benign and this uptake must be differentiated from uptake by malignancies, whether primary or secondary. The most important limitations are active inflammatory or infectious processes, which are positive on PET images, and malignant lesions that are smaller than 1cm, cystic, necrotic, or low-grade, which are negative on PET images. PET/CT in the locomotor apparatus is especially useful for the detection of metastases from the most common tumors. It is also used for staging and monitoring the response to treatment of some hematological tumors like lymphoma, where it is fundamental to determine whether the bone marrow has been infiltrated, or myeloma. Lastly, although it is not yet an established indication, PET/CT is being increasingly used to study sarcomas, because it can provide additional information that can be useful for the characterization and grading of tumors, for guiding biopsies, for staging and re-staging, and for evaluating the response to neoadjuvant therapy as well as for evaluating new drugs in clinical trials.