Tumor thrombus in the large veins draining primary pelvic osteosarcoma on cross sectional imaging

Imaging of abdominopelvic oncologic emergencies

With advancements in cancer treatment, the survival rates for many malignancies have increased. However, both the primary tumors and the treatments themselves can give rise to various complications. Acute symptoms in oncology patients require prompt attention. Abdominopelvic oncologic emergencies can be classified into four distinct categories: vascular, bowel, hepatopancreatobiliary, and bone-related complications. Radiologists need to be familiar with these complications to ensure timely diagnosis, which ultimately enhances patient outcomes.

Breaking down tumor thrombus: Current strategies for medical management

Tumor thrombus, the intravascular extension of tumor into adjacent blood vessels, is frequently encountered in patients with renal cell carcinoma and hepatocellular carcinoma, and often involves the abdominal vasculature including the renal vein, portal vein, and the inferior vena cava. While a bland thrombus is composed of platelets and fibrin, in contrast, a tumor thrombus refers to an organized collection of tumor cells. Though oftentimes detected incidentally on imaging, tumor thrombus may have significant clinical implications and can be challenging to differentiate from bland thrombus. Additionally, the optimal management of tumor thrombus, including the use of anticoagulation, remains poorly described. This review summarizes common causes of tumor thrombus, as well as its impact on staging, prognosis, and treatment.

Thrombus or tumor?

Key clinical message

Contrast defects in veins are often diagnosed as benign thrombi, but depending on the patient's background it is necessary to differentiate between tumor thrombi. It is difficult to differentiate between these using contrast-enhanced CT alone, but with angioscopy it is easy to visually distinguish between a benign and tumor thrombi.

Abstract

Contrast-enhanced computer tomography (CT) performed on a male patient being treated for de-differentiated chondrosarcoma revealed contrast defects in the pulmonary artery and right femoral vein, and a diagnosis of pulmonary artery thromboembolism and venous thromboembolism was made, and oral anticoagulant therapy was started. However, a follow-up CT showed that the contrast defect had extended to the inferior vena cava. Observation using an angioscope revealed that it was not a benign thrombi but a tumor.

Venous Tumor Thrombus in Primary Bone Sarcomas in the Pelvis: A Clinical and Radiographic Study of 451 Cases

BACKGROUND

Few investigations of venous tumor thrombus (VTT) in primary pelvic bone sarcomas are available. We aimed to identify the prevalence, associated factors, and prognosis of VTT across different types of pelvic sarcomas and to propose an algorithm for management.

METHODS

We included 451 consecutive cases of primary, bone-derived, treatment-naive, pelvic sarcomas in this study. Demographic data and the results of initial laboratory tests, imaging examinations, and oncological evaluations were extracted and analyzed. Forty-four cases of VTT were diagnosed with radiographic examinations, and 18 of them were verified histologically.

RESULTS

The cohort consisted of chondrosarcomas (41.2%), osteosarcomas (30.4%), Ewing sarcomas (15.5%), bone-derived undifferentiated pleomorphic sarcomas (5.8%), and other bone sarcomas (7.1%). The prevalence of VTT was 9.8% in the whole group, and associated factors included a lactate dehydrogenase (LDH) level of ≥230.5 U/L and invasion of the L5-S1 intervertebral foramen. Patients with pelvic osteosarcoma had a high prevalence of VTT (22.6%), and the associated factors in this group included a chondroblastic subtype, an LDH level of ≥187 U/L, and invasion of the obturator foramen and the L5-S1 intervertebral foramen. Patients with VTT had a poor prognosis with a median overall survival time of 14 months. Subgroup analyses of localized pelvic osteosarcoma indicated that the presence of VTT decreased the median overall survival time (21.5 versus 54.0 months for those without VTT, p = 0.003), median recurrence-free survival time (18.6 versus 32.4 months, p = 0.020), and median metastasis-free survival time (11.2 versus 41.0 months, p < 0.001).

CONCLUSIONS

VTT is most common in patients with pelvic osteosarcoma as compared with patients with other primary bone sarcomas, and it is associated with several factors. It is a negative prognostic factor. An algorithm for management of pelvic sarcomas with VTT stratified by the classification of the VTT might be beneficial, but further validation is necessary.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Osteoid Tumors of Bone

We present a review of several bone (osteoid)-forming tumors including enostosis, osteoid osteoma, osteoblastoma, and osteosarcoma. These entities were chosen because they are reasonably common-neither seen every day nor rare. When applicable, recent information about the lesions is included.

Identification of Abnormal Spindle Microtubule Assembly as a Promising Therapeutic Target for Osteosarcoma

Objective

To demonstrate the expression of abnormal spindle microtubule assembly (ASPM) in clinical osteosarcoma tissue specimens collected in our hospital, and to explore the function of ASPM in osteosarcoma in vitro and in vivo.

Methods

Tissue specimens from 82 cases of osteosarcoma were collected and analyzed by immunohistochemistry assay. We also investigated the relationship between ASPM expression and clinicopathological characteristics in the patients. We transfected shASPM plasmid and the empty control plasmid, respectively, and then used quantitative polymerase chain reaction and western blot analysis to detect ASPM expression. Cell colony assay and MTT were used to observe the proliferation ability. In vivo study was undertaken to explore the ASPM function further.

Results

In this study, ASPM showed high expression in osteosarcoma tissue samples compared with non‐tumor normal tissues. ASPM was positively correlated with clinical pathological characteristics, including tumor size (P = 0.024) and clinical stage (P = 0.045). Our results further showed that ASPM depletion dramatically inhibited the proliferation of osteosarcoma cells (with fewer cells in the sh‐RNA‐ASPM group compared with the control group(P < 0.05, respectively), and the in vivo assays further confirmed that ASPM ablation markedly blocked tumor growth compared with control (P < 0.05).

Conclusion

Our data provides strong evidence that the high expression of ASPM in osteosarcoma promotes proliferation in vitro and in vivo, indicating its potential role as an osteosarcoma therapeutic target.

Multimodality Imaging of Abdominopelvic Tumors with Venous Invasion

A broad range of abdominal and pelvic tumors can manifest with or develop intraluminal venous invasion. Imaging features at cross-sectional modalities and contrast-enhanced US that allow differentiation of tumor extension within veins from bland thrombus include the expansile nature of tumor thrombus and attenuation and enhancement similar to those of the primary tumor. Venous invasion is a distinctive feature of hepatocellular carcinoma and renal cell carcinoma with known prognostic and treatment implications; however, this finding remains an underrecognized characteristic of multiple other malignancies-including cholangiocarcinoma, adrenocortical carcinoma, pancreatic neuroendocrine tumor, and primary venous leiomyosarcoma-and can be a feature of benign tumors such as renal angiomyolipoma and uterine leiomyomatosis. Recognition of tumor venous invasion at imaging has clinical significance and management implications for a range of abdominal and pelvic tumors. For example, portal vein invasion is a strong negative prognostic indicator in patients with hepatocellular carcinoma. In patients with rectal cancer, diagnosis of extramural venous invasion helps predict local and distant recurrence and is associated with worse survival. The authors present venous invasion by vascular distribution and organ of primary tumor origin with review of typical imaging features. Common pitfalls and mimics of neoplastic thrombus, including artifacts and anatomic variants, are described to help differentiate these findings from tumor in vein. By accurately diagnosing tumor venous invasion, especially in tumors where its presence may not be a typical feature, radiologists can help referring clinicians develop the best treatment strategies for their patients. ^©RSNA, 2020.

Comparison of ferumoxytol- and gadolinium chelate-enhanced MRI for assessment of sarcomas in children and adolescents

OBJECTIVES

We compared the value of ferumoxytol (FMX)- and gadolinium (Gd)-enhanced MRI for assessment of sarcomas in paediatric/adolescent patients and hypothesised that tumour size and morphological features can be equally well assessed with both protocols.

METHODS

We conducted a retrospective study of paediatric/adolescent patients with newly diagnosed bone or soft tissue sarcomas and both pre-treatment FMX- and Gd-MRI scans, which were maximal 4 weeks apart. Both protocols included T1- and T2-weighted sequences. One reader assessed tumour volumes, signal-to-noise ratios (SNR) of the primary tumour and adjacent tissues and contrast-to-noise ratios (CNR) of FMX- and Gd-MRI scans. Additionally, four readers scored FMX- and Gd-MRI scans according to 15 diagnostic parameters, using a Likert scale. The results were pooled across readers and compared between FMX- and Gd-MRI scans. Statistical methods included multivariate analyses with different models.

RESULTS

Twenty-two patients met inclusion criteria (16 males, 6 females; mean age 15.3 ± 5.0). Tumour volume was not significantly different on T1-LAVA (p = 0.721), T1-SE (p = 0.290) and T2-FSE (p = 0.609) sequences. Compared to Gd-MRI, FMX-MRI demonstrated significantly lower tumour SNR on T1-LAVA (p < 0.001), equal tumour SNR on T1-SE (p = 0.104) and T2-FSE (p = 0.305), significantly higher tumour-to-marrow CNR (p < 0.001) on T2-FSE as well as significantly higher tumour-to-liver (p = 0.021) and tumour-to-vessel (p = 0.003) CNR on T1-LAVA images. Peritumoural and marrow oedema enhanced significantly more on Gd-MRI compared to FMX-MRI (p < 0.001/p = 0.002, respectively). Tumour thrombi and neurovascular bundle involvement were assessed with a significantly higher confidence on FMX-MRI (both p < 0.001).

CONCLUSIONS

FMX-MRI provides equal assessment of the extent of bone and soft tissue sarcomas compared to Gd-MRI with improved tumour delineation and improved evaluation of neurovascular involvement and tumour thrombi. Therefore, FMX-MRI is a possible alternative to Gd-MRI for tumour staging in paediatric/adolescent sarcoma patients.

KEY POINTS

• Ferumoxytol can be used as an alterative to gadolinium chelates for MRI staging ofpaediatric sarcomas. • Ferumoxytol-enhanced MRI provides equal assessment of tumour size and other diagnostic parameters compared to gadolinium chelate-enhanced MRI. • Ferumoxytol-enhanced MRI provides improved delineation of sarcomas from bone marrow, liver and vessels compared to gadolinium chelate-enhanced MRI.

APLNR promotes the progression of osteosarcoma by stimulating cell proliferation and invasion

Osteosarcoma is the most common type of bone malignancies with a poor prognosis. In recent years, targeted therapy has shown great potential in the treatment of osteosarcoma, and more effective therapeutic targets for this disease need to be developed. APLNR is a seven transmembrane G-protein-coupled receptor expressed widely in multiple tissues. As has been reported, APLNR is involved in various physiological and pathological processes. Although APLNR plays a role in the development and progression of multiple tumors, the potential role of APLNR in osteosarcoma, a highly malignant tumor, remains unclear. Here, we reported that APLNR expression was correlated positively with clinical features including tumor size and stage of osteosarcoma. We found that APLNR knockdown inhibited the proliferation and invasion of osteosarcoma cells in vitro. In addition, APLNR could promote the progression and metastasis of osteosarcoma in mice. Collectively, this study showed the potential link between APLNR and osteosarcoma and suggested APLNR as a novel therapeutic target for osteosarcoma.

Tumor thrombus in the venous drainage pathways of primary, recurrent and metastatic disease on routine oncologic imaging studies: beyond hepatocellular and renal cell carcinomas

Radiologists routinely evaluate for tumor thrombus in the portal and hepatic veins in patients with hepatocellular carcinoma and in the renal vein and inferior vena cava in patients with renal cell carcinoma. However, tumor thrombus occurs in association with numerous other tumor types, e.g. colorectal carcinoma and pancreatic neuroendocrine tumor. Furthermore tumor thrombi are not limited to the primary tumor but also seen with local recurrence and metastatic disease. While less recognized, these thrombi nevertheless affect patterns of recurrence and prognosis. Their detection is critical for accurate local staging and early detection of local recurrence and metastatic disease. The purpose of this pictorial review is to draw the attention of radiologists to the less familiar manifestations of tumor thrombus, review the imaging findings and illustrate the clinical significance of these thrombi.