Value of 18F-FDG PET/CT in differentiating malignancy of pulmonary artery from pulmonary thromboembolism: a cohort study and literature review

Emerging multimodality imaging techniques for the pulmonary circulation

Pulmonary hypertension (PH) remains a challenging condition to diagnose, classify and treat. Current approaches to the assessment of PH include echocardiography, ventilation/perfusion scintigraphy, cross-sectional imaging using computed tomography and magnetic resonance imaging, and right heart catheterisation. However, these approaches only provide an indirect readout of the primary pathology of the disease: abnormal vascular remodelling in the pulmonary circulation. With the advent of newer imaging techniques, there is a shift toward increased utilisation of noninvasive high-resolution modalities that offer a more comprehensive cardiopulmonary assessment and improved visualisation of the different components of the pulmonary circulation. In this review, we explore advances in imaging of the pulmonary vasculature and their potential clinical translation. These include advances in diagnosis and assessing treatment response, as well as strategies that allow reduced radiation exposure and implementation of artificial intelligence technology. These emerging modalities hold the promise of developing a deeper understanding of pulmonary vascular disease and the impact of comorbidities. They also have the potential to improve patient outcomes by reducing time to diagnosis, refining classification, monitoring treatment response and improving our understanding of disease mechanisms.

Isolated pulmonary artery choriocarcinoma masquerading as pulmonary embolism diagnosed by endovascular biopsy

Pulmonary arteries may rarely be involved by primary and secondary tumors. Clinical and imaging features mimic those of PE making it challenging to diagnose. Choriocarcinoma is a malignant germ cell tumor, typically in the female genital tract. Rarely, they can present as PA thrombus. Female patients with a history of a molar pregnancy, ectopic pregnancy, abortion or in this case a miscarriage, are at a higher risk of gestational trophoblastic disease which can manifest in this way, albeit this is rare. In this report we describe the case of a 52-year-old female who presented with a 1 month history of worsening dyspnea and pleuritic lower thoracic pain. A diagnosis of pulmonary embolism (PE) was confirmed on CT pulmonary angiogram, with a large volume thrombus in the left pulmonary artery (PA). She failed to improve on standard anticoagulation therapy and was found to have a raised beta-human chorionic gonadotropin of >100,000. This leads to an extensive malignancy work-up. The only pertinent finding was that of increased fluorodeoxyglucose (FDG) accumulation in the PA thrombus. Endovascular biopsy of the thrombus was performed, and the patient was diagnosed with choriocarcinoma of the PA. This case highlights the importance of further investigation in patients failing to respond to anticoagulation therapy for PE. It also illustrates the role of interventional radiology in obtaining histological diagnosis in patient's presenting with PA tumor thrombus.

The diagnostic value of [18F]FAPI-42 PET/CT for pulmonary artery masses: comparison with [18F]FDG PET/CT

OBJECTIVES

To investigate the potential utility of [18F]fibroblast activation protein inhibitor (FAPI) positron emission tomography/computed tomography (PET/CT) for evaluating pulmonary artery (PA) masses, and compare it with [18F]fluorodeoxyglucose (FDG) PET/CT.

METHODS

Participants with clinically suspected PA malignancy were prospectively enrolled and underwent dual-tracer PET/CT ([18F]FAPI-42 and [18F]FDG) imaging. Visual analysis and semi-quantitative parameters were compared between the two types of radiotracers. The tissue specimen underwent immunohistochemical staining to verify FAP expression in the tissue.

RESULTS

Thirty-three patients (18 males/15 females; mean age 53.1 ± 15.4 years) were enrolled. All 21 patients with malignant PA masses were FDG-positive (100%), whereas 20 out of 21 patients were FAPI-positive (95.2%). All 12 patients with benign PA masses were both negative in FDG and FAPI PET. The mean maximum standardized uptake value (SUVmax) and target-to-background ratio (TBR) of FAPI and FDG in malignant PA masses were significantly higher than those of benign masses. Although there was no significant difference in SUVmax between FDG and FAPI in malignant PA masses (11.36 vs. 9.18, p = 0.175), the TBR (liver) and TBR (left ventricle) were more favorable for FAPI than for FDG (13.04 vs. 5.17, p < 0.001); (median: 7.75 vs. 2.75, p = 0.007). Immunohistochemical analysis (n = 16) validated that the level of FAP expression corresponded strongly to the uptake of FAPI in PET/CT scans (rs = 0.712, p = 0.002). For clinical management, FAPI PET found more metastatic lesions than FDG PET in 4 patients, with 2 patients upgrading and 1 patient changing treatment decisions.

CONCLUSIONS

FAPI PET/CT is feasible in the diagnosis of PA masses. Although not superior to FDG PET/CT, FAPI PET/CT showed better target-to-background contrast.

CLINICAL RELEVANCE STATEMENT

This study found that FAPI PET/CT is not superior to FDG PET/CT in diagnosing PA masses, but FAPI PET/CT displays better target-to-background contrast and more positive lesions, which may help improve disease management.

KEY POINTS

Pulmonary malignancies lack specificity in clinical manifestations, laboratory tests, and routine imaging examinations. FAPI PET/CT is not diagnostically better than FDG PET/CT but displays better target-to-background contrast and more positive lesions. Dual-tracer PET/CT ([18F]FAPI-42 and [18F]FDG) imaging improves clinical management of pulmonary artery masses.

Pulmonary tumor embolism in a maintenance hemodialysis patient with hepatocellular carcinoma

Patients with chronic kidney disease are already at an increased risk for pulmonary embolism, since loss of renal function rendered a procoagulant state. Further, malignant tumor is a well-established risk factor for pulmonary thromboembolism. Alternatively, occlusion of the pulmonary vasculature by tumor cells per se and associated thrombi may mimic thromboembolic disease. By comparison, however, report of pulmonary tumor embolism (PTE) in patients on maintenance hemodialysis (MHD) is exceedingly rare. A less vigilant clinician may have otherwise treated this situation as fluid overload or thromboembolic disorder. We herein described in an MHD patient such an unusual case of PTE, which was diagnosed by contrast-enhanced CT and PET/CT. As such, our work may expand the knowledge reserve of dialysis staffs about this rare complication of malignancy.

A primary pulmonary artery sarcoma masquerading pulmonary embolism: a case report and literature review

BACKGROUND

Primary pulmonary artery sarcoma (PAS) is an extremely rare malignant tumor with a poor prognosis. The clinical manifestations of PAS are diverse, including dyspnea, chest pain, cough, and hemoptysis. The poor prognosis is often due to delayed diagnosis caused by similarity in imaging findings with pulmonary thromboembolism (PTE). These cues of diagnosis include the "wall eclipsing sign", lobulated bulging margins, gadolinium enhancement during MRI imaging, and FDG uptake during PET/CT imaging. However, there are still many misdiagnoses.

CASE PRESENTATION

This article reports a woman of reproductive age presenting with a pulmonary artery mass. The computed tomographic pulmonary angiography and positron emission tomography/computed tomography did not show obvious signs of pulmonary artery sarcoma, however, contrast-enhanced echocardiography showed moderate perfusion, which helped differentiate between pulmonary artery sarcoma and pulmonary artery thrombosis, leading to timely surgical treatment.

CONCLUSIONS

PAS is a rare form of cancer that can occasionally be visually similar to PTE on radiographic images. Early diagnosis of PAS is of vital importance to the prognosis of the patients. There are several visual cues that can help differentiate between the two conditions. Additionally, contrast-enhanced echocardiography provides additional information on tumor perfusion, offering another effective approach for a prompt and accurate diagnosis.

[Chronic thromboembolic pulmonary hypertension]

Chronic thromboembolic pulmonary disease (CTEPD) is an important late complication of acute pulmonary embolism, in which the thrombi transform into fibrous tissue, become integrated into the vessel wall, and lead to chronic obstructions. CTEPD is differentiated into cases without pulmonary hypertension (PH), characterized by a mean pulmonary arterial pressure up to 20 mmHg and a form with PH. Then, it is still referred to as chronic thromboembolic pulmonary hypertension (CTEPH).When there is suspicion of CTEPH, initial diagnostic tests should include echocardiography and ventilation/perfusion scan to detect perfusion defects. Subsequently, referral to a CTEPH center is recommended, where further imaging diagnostics and right heart catheterization are performed to determine the appropriate treatment.Currently, three treatment modalities are available. The treatment of choice is pulmonary endarterectomy (PEA). For non-operable patients or patients with residual PH after PEA, PH-targeted medical therapy, and the interventional procedure of balloon pulmonary angioplasty (BPA) are available. Increasingly, PEA, BPA, and pharmacological therapy are combined in multimodal concepts.Patients require post-treatment follow-up, preferably at (CTE)PH centers. These centers are required to perform a minimum number of PEA surgeries (50/year) and BPA interventions (100/year).

Echocardiographic Characteristics of Pulmonary Artery Intimal Sarcoma: Comparison With CTPA

OBJECTIVES

This study examined the echocardiographic characteristics of patients with pulmonary artery intimal sarcoma (PAIS) and compared the results with those from computed tomographic pulmonary angiography (CTPA).

METHOD

Twenty-six (26) patients were diagnosed with PAIS at the current institution during the study period, and 23 were eligible for analysis. Echocardiography and CTPA examinations were performed in all enrolled patients.

RESULTS

The echocardiography results showed that most lesions had expansive growth in the left pulmonary artery (PA); the right PA; or a combination of the left PA, right PA, and main PA, with extension to the pulmonary valve and/or right ventricular outflow tract. These lesions also had distinctive sieve-like echogenic signals. Echocardiography also showed that some lesions had lobulated shapes, were nearly round and echolucent or with calcifications, and moved during imaging. The lesion distribution was similar in CTPA and echocardiography (p=0.361), but CTPA was more sensitive in detection of the complete shape (p=0.023).

CONCLUSIONS

The unique echocardiographic characteristics of PAIS, especially the "sieve sign", could help in the diagnosis of this cancer. Transthoracic echocardiography is a non-invasive technique that appears effective in detecting PAIS.

Vascular Malformations and Tumors: A Review of Classification and Imaging Features for Cardiothoracic Radiologists

The International Society for the Study of Vascular Anomalies (ISSVA) classification is a comprehensive histology-based scheme that was updated in 2018. It is important for cardiothoracic imagers to understand this classification to ensure that accurate terminology is used and that archaic terms are avoided when vascular lesions are described. Knowledge of the various malformations (including common conditions, such as venous malformation, arteriovenous fistula, and arteriovenous malformation) and vascular tumors allows for timely diagnosis and appropriate management. This review describes various vascular anomalies, in accordance with ISSVA classification and terminology; highlights key imaging features associated with each; and discusses the role of different imaging modalities. Keywords: Pulmonary, Soft Tissues/Skin, Vascular, Arteriovenous Malformation © RSNA, 2023.

Percutaneous endovascular biopsy for the diagnosis of pulmonary artery masses: A preliminary study of single-center

Percutaneous endovascular biopsy (PEB) including forceps biopsy and catheter aspiration has been used to make a pretreatment diagnosis for pulmonary artery (PA) masses. This retrospective study aims to describe the procedure of PEB and compare the diagnostic yield of forceps biopsy and catheter aspiration for a definite diagnosis in patients with PA masses. All consecutive 22 patients (53 ± 14 years), 11 males and 11 females, who underwent PEB for pathologic confirmation between November 2018 and November 2022 were enrolled. All 22 patients performed computed tomography pulmonary angiography or positron emission tomography-computed tomography to confirm the filling defects suspicious for PA malignancy before intervention. And then, all patients underwent PEB successfully without acute or fatal complications, including both forceps biopsy and catheter aspiration in 15 cases, only forceps biopsy in 5 cases, and only catheter aspiration in 2 cases. Histopathological analysis provided a definite diagnosis in all PEBs with a clinical success of 91.0% (20/22). Among them, in 15 patients who underwent both forceps biopsy and aspiration biopsy, the technical success using forceps biopsy was 93.3% (14/15), and aspiration biopsy was 6.7% (1/15), and there was a significant difference in diagnostic accuracy when comparing two techniques. Twenty-one out of 22 PA masses (95.5%) were malignant, of which, the most frequent malignant lesion observed was PA sarcoma (66.7%, 14/21). Benign lesion included one thrombus (4.5%, 1/22). In conclusion, PEB is an effective and safe diagnostic method for differentiating benign and malignant PA masses and could be peformed when PA masses appeared clinically malignant.

Pulmonary artery intimal sarcoma: A rare cause of filling defects in pulmonary arteries

Pulmonary artery intimal sarcomas are very rare and arise from primitive pluripotent mesenchymal cells. They are often misdiagnosed as pulmonary thromboembolism, leading to futile anticoagulation treatment and delayed diagnosis. We present a case of a patient who showed nonspecific pulmonary symptoms and characteristic imaging manifestation. Progressive symptoms and additional imaging led to the suspicion of a pulmonary artery intimal sarcoma, which was finally confirmed by pathological biopsy. This case serves as a reminder to consider pulmonary artery intimal sarcomas in the differential diagnosis of patients with dyspnea and filling defects on computed tomography pulmonary angiography or contrast-enhanced computed tomography.

Pulmonary thromboembolic disease or pulmonary artery intimal sarcoma: Case report and literature review

The present case study reported on a patient initially diagnosed with pulmonary embolism at the First Affiliated Hospital of Fujian Medical University (Fuzhou, China) in May 2021. Furthermore, a relevant literature review was performed. The patient was a 57-year-old Chinese male who presented with dyspnea and wheezing following exercise. Physical examination revealed pulmonary valve second heart sound > aortic valve second heart sound but lack of swelling on both lower limbs, while the imaging results suggested pulmonary artery filling defects. Initially, the patient was diagnosed with pulmonary embolism and was administered anticoagulation treatment, which lasted for 3 months but proved to be ineffective. Subsequent re-examination via chest computed tomography further indicated multiple nodules in the left hilum and lung. Therefore, the patient was hospitalized for lung aspiration biopsy, which led to the final diagnosis of pulmonary artery intimal sarcoma based on the pathological review.

Improving the imaging diagnostic strategy for pulmonary artery masses based on 18F-FDG PET/CT integrated with CTPA

OBJECTIVE

To evaluate the diagnostic accuracy of computed tomography pulmonary angiography (CTPA) and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for pulmonary artery (PA) masses.

METHODS

Of 2889 patients with PA filling defects of PA on CTPA, 79 consecutive patients suspicious for PA malignancy who subsequently underwent ¹⁸F-FDG PET/CT were enrolled. All masses were diagnosed on the basis of pathological findings or clinical imaging follow-up. For each mass, morphological CT signs, standardized uptake value (SUVmax and SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) on ¹⁸F-FDG PET/CT were used as diagnostic markers.

RESULTS

Expansive growth, irregular margin, invasion, CT contrast uptake, and wall eclipse sign were strongly associated with the malignant nature of masses. The coexistence of at least 5 CT signs perfectly identified malignant masses, whereas the detection of no more than 4 CT signs did not accurately discriminate between the natures of masses. Mean SUVmax, SUVmean, MTV, and TLG values were significantly higher in malignant masses compared to those in benign masses. The diagnostic accuracy of ¹⁸F-FDG PET/CT parameters (SUV, MTV, and TLG) was excellent in detecting malignant masses. Among patients with 3 or 4 pathological CT signs, SUVmax > 3.4 significantly increased the identification of malignancies.

CONCLUSIONS

CTPA is a useful imaging modality for diagnosing PA masses, especially when at least 5 abnormal CT signs are identified. Similarly, ¹⁸F-FDG PET/CT accurately identified malignant masses and provided additional valuable information on diagnostic uncertainties after CTPA.

Clinical utility of 18F-FDG PET/CT imaging in patients with pulmonary artery sarcoma

Background

Pulmonary artery sarcoma (PAS) is a rare and fatal malignancy. Due to the lack of specific clinical and radiological features, PAS is always misdiagnosed as pulmonary thromboembolism (PTE). This study aimed to investigate ¹⁸F-FDG PET/CT in distinguishing PAS from PTE, and analyze its correlation with clinical and radiological findings and outcome of PAS.

Methods

Clinical, contrast-enhanced CT, and ¹⁸F-FDG PET/CT characteristics of 14 patients with PAS and 33 patients with PTE were retrospectively reviewed. The correlation between PET/CT metabolic parameters vs. clinical and CT findings was investigated in patients with PAS. The overall survival (OS) was analyzed in PAS patients.

Results

The SUVmax of PAS (median: 8.0, range 3.0–17.2) was significantly higher than PTE (1.8[0.8–3.7]) (P < 0.001), and at a cutoff value of 2.9, the sensitivity and specificity were 100.0% and 93.9%, respectively. Compared with PTE, PAS more frequently occurred in younger population (P = 0.011), involved pulmonary trunk (P < 0.001), and displayed higher enhanced CT (P < 0.001) and ΔCT (enhanced CT compared to non-enhanced CT) (P < 0.001) values. SUVmax of PAS was associated with tumor staging (P = 0.022) and enhanced CT (P = 0.013) and ΔCT (P = 0.005) values. The median OS of PAS patients was 10.5 months, and 12-month and 24-month OS rates were 58.0% and 12.0%, respectively. Only D-dimer level (P = 0.038) and tumor staging (P = 0.019) were associated with OS.

Conclusions

Most PAS displayed high glucometabolism, and SUVmax of ¹⁸F-FDG PET/CT was useful in distinguishing PAS from PTE.

Value of 18F-FDG PET/CT Combined with Lung HRCT in Diagnosis of Solitary Pulmonary Intravascular Metastasis

Background

Solitary pulmonary intravascular metastasis is a rare complication of malignant tumors, and accurate diagnosis can improve clinical decision-making, but diagnosing it effectively using conventional techniques is difficult.

Purpose

To explore the value of ¹⁸F-FDG PET/CT combined with lung high-resolution computed tomography (HRCT) in the diagnosis of solitary pulmonary intravascular metastasis.

Methods

¹⁸F-FDG PET/CT, lung HRCT, and follow-up data of 18,143 cancer patients were retrospectively analyzed to select patients with pulmonary vessel involvement besides the primary tumor only. The histopathological or imaging follow-up results were used as the diagnostic criteria for pulmonary intravascular metastasis.

Results

A total of 13 patients with 17 pulmonary intravascular metastases were found, of which 9 patients had a single lesion and 4 had double. The SUVmax was 1.1–5.4 (average, 2.4 ± 1.4), and the length of hypermetabolic metastasis was 5.1–24.1 mm (average, 10.7 ± 6.5 mm). All the intravascular metastases were located in the terminal pulmonary vessels. Strip or branched pulmonary vessels enlargement with increased metabolism was the main imaging manifestation (15/17, 88.2%), while the other 2 cases only showed strip metabolic enhancement without abnormalities in pulmonary vessels (2/17, 11.8%). Four pulmonary intravascular metastases were confirmed by pathology, and the other 13 cases were diagnosed by imaging follow-up.

Conclusion

¹⁸F-FDG PET/CT combined with lung HRCT is an effective technique for the diagnosis of solitary pulmonary intravascular metastasis. High-strip or branched FDG uptake in the distal pulmonary vessel accompanied by corresponding morphological changes in patients with malignant tumors can be used as a specific diagnostic indicator.

PET-Based Imaging with 18F-FDG and 18F-NaF to Assess Inflammation and Microcalcification in Atherosclerosis and Other Vascular and Thrombotic Disorders

Positron emission tomography (PET) imaging with ¹⁸F-fluorodeoxyglucose (FDG) represents a method of detecting and characterizing arterial wall inflammation, with potential applications in the early assessment of vascular disorders such as atherosclerosis. By portraying early-stage molecular changes, FDG-PET findings have previously been shown to correlate with atherosclerosis progression. In addition, recent studies have suggested that microcalcification revealed by ¹⁸F-sodium fluoride (NaF) may be more sensitive at detecting atherogenic changes compared to FDG-PET. In this review, we summarize the roles of FDG and NaF in the assessment of atherosclerosis and discuss the role of global assessment in quantification of the vascular disease burden. Furthermore, we will review the emerging applications of FDG-PET in various vascular disorders, including pulmonary embolism, as well as inflammatory and infectious vascular diseases.

Pedunculated pulmonary artery intimal sarcoma with poor uptake in 18F-FDG PET/CT: A case report

Pulmonary artery intimal sarcoma (PAIS) is a rare tumor with an incidence of 0.001%-0.03% that usually grows along artery walls and absorbs fluorodeoxyglucose. It is difficult to distinguish PAIS from pulmonary thromboembolism due to the similarities of their symptoms. Therefore, contrast-enhanced computed tomography and positron emission tomography-computed tomography (PET-CT) should be used to establish a correct diagnosis. Here we report a case of an extremely rare type of PAIS, pedunculated PAIS, which could not be visualized on PET-CT. Histological features of a tumor with a low accumulation of fluorodeoxyglucose revealed low-cellularity and necrotizing background. Multimodal imaging was useful to diagnose PET-CT negative PAIS accurately. <Learning objective: Pedunculated pulmonary artery intimal sarcoma (PAIS) is a rare form of neoplasm. You need to know that PAIS which has low cellularity with marked interstitial myxoid tissue cannot be detected on positron emission tomography-computed tomography.>.

Dual-Energy CT for Pulmonary Embolism: Current and Evolving Clinical Applications

Pulmonary embolism (PE) is a potentially fatal disease if the diagnosis or treatment is delayed. Currently, multidetector computed tomography (MDCT) is considered the standard imaging method for diagnosing PE. Dual-energy CT (DECT) has the advantages of MDCT and can provide functional information for patients with PE. The aim of this review is to present the potential clinical applications of DECT in PE, focusing on the diagnosis and risk stratification of PE.

Clinical Features and Outcomes of Pulmonary Artery Sarcoma

OBJECTIVES

A retrospective cohort study was designed to describe the clinical features and outcomes of pulmonary artery sarcoma (PAS).

METHODS

Twenty-two (22) consecutive patients diagnosed with PAS by pathological examination were enrolled and followed up until they died or until January 2020. The medical records were retrospectively reviewed to evaluate the clinical characteristics, image findings, and outcomes.

RESULTS

1) Twenty-one (21, 95.5%) patients were firstly misdiagnosed. Dyspnoea was the most common presenting symptom (19 of 22, 86.4%). 2) Filling defects in the right pulmonary artery were seen in 17 patients (77.3%) with computed tomography pulmonary angiography or magnetic resonance pulmonary angiography. Among those patients, 14 underwent positron emission tomography-computed tomography detection and 13 (92.9%) were found to have increased uptake value in the pulmonary artery. 3) The median survival (from diagnosis to death or January 2020) of the total series was 11.6 months (range, 0.7-68.5 months). The estimated cumulative survival rates at 1, 2, and 3 years were 52.6%, 32.8%, and 19.7%, respectively. Patients who received surgery and/or chemo-radiotherapy treatment had a better survival rate compared with patients without treatment (the estimated cumulative survival rates at 1, 2, and 3 years were 60.3%, 39.1%, and 29.3%, respectively, vs 33.3%, 16.6%, and 0, accordingly) and better survival time (median survival 17.02 vs 3.16 months, respectively) (p=0.025).

CONCLUSIONS

Pulmonary artery sarcoma is easily misdiagnosed, as the symptoms and routine image detection are nonspecific. Positron emission tomography-computed tomography may be helpful in diagnosis. Surgery and/or chemo-radiotherapy offer a chance for better outcomes.

Pulmonary artery intimal sarcoma - A primeval or rediscovered tumor? A report of 14 new cases with literature review

Pulmonary artery sarcomas (PAS) are rare with many being undifferentiated pleomorphic or spindle cell (UPSC) sarcomas with variable atypia. The term pulmonary artery intimal sarcoma (PAIS) was rarely coined in the early literature and sometimes used for luminal sarcomas. With the advent of immunohistochemistry and molecular genetics, many of these UPSC sarcomas were found to frequently overpress MDM2 and/or CDK4 and PDGFRA with genetic alterations in 12q12-15 and 4q12, where the MDM2, CDK4 and PDGFRA genes are located. These recent developments enabled refinement in diagnosis of PAIS. We diagnosed 14 cases of PAIS (6 males and 8 females, mean age 44 years) in 2015 - 2020 in our institution. Six were initially misdiagnosed as thromboembolism and the remaining pulmonary artery tumors. The tumors were pulmonary artery intraluminal polypoid masses with histology of spindle cell sarcomas exhibiting immunohistochemical positivity for MDM2 (100%) and CDK4 (79%) with MDM2 gene amplification (100%). Ten surgically treated patients fared better than four other biopsy only and not surgically treated patients, who died of disease within 5-11 months. PAIS needs to be differentiated from other spindle cell tumors and those exhibiting MDM2 gene amplification, especially dedifferentiated liposarcoma. The use of biopsy to provide diagnostic material poses a sampling error problem and correlation with clinical, radiologic, histologic, immunophenotypic and genotypic features are essential for accurate diagnosis and early surgical intervention of PAIS.

Undifferentiated intimal sarcoma of the pulmonary artery: A case report

BACKGROUND

Since 1923, only a few hundred cases of pulmonary arterial sarcoma (PAS) have been reported. It is easy for PAS to be misdiagnosed as pulmonary thromboembolism, which makes treatment difficult. The median survival time without surgical treatment for PAS is only 1.5-3 mo. Echocardiography is widely used in screening for pulmonary artery space-occupying lesions in patients with chest pain, dyspnea, and cough; furthermore, it is typically considered the first imaging examination for patients with PAS.

CASE SUMMARY

In May 2017, a 39-year-old male patient experienced chest pain with no particular obvious cause. At that time, the cause was thought to be pulmonary embolism. In July 2017, positron emission tomography–computed tomography revealed space-occupying lesions in the right lung and multiple metastases in both lungs. The lesions of the right lung were biopsied, and pathology revealed undifferentiated sarcoma. Chemotherapy had been performed since July 2017 in another hospital. In December 2019, the patient was admitted to our hospital for the sake of CyberKnife treatment. Echocardiography suggested: (1) A right ventricular outflow tract (RVOT) solid mass of the main pulmonary artery; and (2) mild pulmonary valve regurgitation. Ultrasonography showed the absence of a thrombus in the deep veins of either lower limb.

CONCLUSION

PAS is a single, central space-occupying lesion involving the RVOT and pulmonary valve. Echocardiography of PAS has its own characteristics.

A case of pulmonary tumor embolism diagnosed with respiratory distress immediately after FDG-PET/CT scan

Acute distress immediately following an ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) scan is an exceedingly rare event. We report a case whose condition was suddenly deteriorated in the nuclear medicine laboratory, and whose diagnosis was confirmed by FDG-PET/CT. A 67-year-old woman with left renal cell carcinoma (RCC) suddenly complained of dyspnea and tachycardia just after undergoing FDG-PET/CT. PET/CT images showed increased FDG uptakes in the left renal vein, inferior vena cava, right atrium, and bilateral hila. She was diagnosed with a massive tumor embolism from the inferior vena cava to both pulmonary arteries, and urgently underwent tumor embolectomy. FDG-PET/CT was helpful for diagnosing the tumor embolism and differentiating it from bland thromboembolism in this patient with RCC.

The Diagnostic Value of FDG PET/CT and Thin-Slice High-Resolution Chest CT in Pulmonary Intravascular Metastasis

OBJECTIVE. Pulmonary intravascular metastasis is a special type of pulmonary metastasis of malignancies; however, few relevant studies have been performed. This study aimed to determine the characteristics of pulmonary intravascular metastasis and improve understanding of the disease by retrospective analysis of FDG PET/CT and thin-layer high-resolution CT (HRCT) imaging of the chest in patients with tumors. MATERIALS AND METHODS. We identified all patients who underwent FDG PET/CT at two hospitals between January 2016 and February 2019 and conducted a comparative analysis of HRCT and PET/CT images. In total, 84 patients (38 women and 46 men) ranging in age from 35 to 82 years old (mean age, 54.7 ± 14.5 [SD] years) participated in the study. Patient characteristics were summarized, and diagnosis was confirmed by chest CT or PET/CT follow-up. RESULTS. A total of 260 pulmonary intravascular metastases were found, which were classified as type I (no significant abnormality, n = 5), type II (abrupt and uneven thickening of the pulmonary vessel, n = 118), type III (simultaneous invasion of adjacent pulmonary vessel, n = 121), and type IV (large strip-shaped high-density mass, n = 16). The majority were located in peripheral pulmonary vessels (94.2% [245/260]). FDG up-take was increased in 252 lesions, and the mean SUV_max was 4.6 ± 2.5. CONCLUSION. The combination of PET/CT and chest HRCT is an effective approach for detecting pulmonary intravascular metastasis. The linear pattern of FDG uptake, abnormal pulmonary blood vessel morphology, and location (below the lung segment) are specific indicators for the diagnosis of pulmonary intravascular metastasis and should be recognized by clinicians and radiologists.

Smooth Muscle Conditions of the Chest: A Clinical, Radiologic, and Pathologic Review

Smooth muscle conditions of the chest have diverse clinical and imaging manifestations and may involve nearly every thoracic structure. Differentiation among these conditions requires the integration of clinical, radiologic, and histopathologic data. Histologic examination in conjunction with immunohistochemistry is essential for differentiation from other spindle cell neoplastic mimics. Familiarity with these entities will ensure the inclusion of smooth muscle conditions in the differential diagnosis of thoracic soft tissue lesions and potentially guide the clinician in appropriate management. We review the clinical, imaging, and histopathologic features of thoracic smooth muscle-related conditions organized by the anatomic structures affected.

Pulmonary artery intimal sarcoma: a case report and literature review

Pulmonary artery intimal sarcoma is a rare disorder arising from the intima of the pulmonary artery. Histopathology reveals that it is a tumour cell of mesenchymal origin. The signs and symptoms include chronic shortness of breath and other features of right ventricular failure, which mimic chronic pulmonary thromboembolism. The definitive diagnosis can rarely be made based on the symptoms and signs alone, and other investigations including echocardiography, computed tomography, magnetic resonance imaging (MRI), and positron emission tomography (PET) are often required. The gold standard for diagnosis is tissue biopsy. The mainstay for treatment is surgery, and complete surgical resection with endarterectomy provides survival benefit. According to recent evidences, however, multimodal treatment provides better survival outcomes than monotherapy such as surgery alone. Despite the newer upcoming treatment strategies, patients with pulmonary intimal sarcoma continue to have a poor prognosis. We present a case of pulmonary artery intimal sarcoma and review the literature associated with the disease.

Whole-exome sequencing insights into pulmonary artery sarcoma mimicking pulmonary embolism: a case report and review

Pulmonary artery sarcoma (PAS) is a rare and aggressive mesenchymal tumor that often mimics thromboembolic disease. Due to its rare and fatal nature, patients are often underdiagnosed or misdiagnosed. There is still no consensus regarding the diagnosis and treatment of PAS. We present a case of a 63 year old male misdiagnosed with pulmonary thromboembolism who received anticoagulant therapy. ¹⁸FDG positron emission tomography (PET) integrated with computed tomography (PET/CT) and subsequent surgery led to the final diagnosis of PAS. Whole exome sequencing of the tissue identified the genetic alterations profile of PAS: copy number variation (CNV) of KIT and mutations of TP53, PIK3CA, IL7R and ATR. Treated with chemotherapy followed by anlotinib, the patient's survival time was 8 months after firm diagnosis. To our knowledge, anlotinib used as a treatment for PAS has not been reported.