Usefulness of fluorodeoxyglucose positron emission tomography in malignancy of pulmonary artery mimicking pulmonary embolism

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 arterial sarcoma: A case report

RATIONALE

Pulmonary artery sarcoma (PAS) is a rare malignant tumor primarily originating from the pulmonary artery's intima or subintima. Approximately one-third of cases are classified as undifferentiated type. Its clinical manifestations lack specificity, dyspnea is the main symptom but can also present with chest pain, cough, hemoptysis, and other discomforts, making it prone to misdiagnosis as pulmonary embolism (PE).

PATIENT CONCERNS

A 50-year-old woman was admitted to the hospital with "dyspnea for more than 3 months, aggravated for 2 days," and computed tomography pulmonary angiography suggesting "bilateral multiple pulmonary embolisms."

DIAGNOSES

The patient was initially misdiagnosed as PE, and was later definitively diagnosed as undifferentiated pleomorphic sarcoma of the pulmonary artery by pathologic biopsy.

INTERVENTIONS AND OUTCOMES

The patient was initially treated with anticoagulant therapy, but her dyspnea was not relieved. After that, she underwent positron emission computed tomography (PET-CT) and other investigations, which suggested the possibility of PAS, and then she underwent pulmonary endarterectomy to remove the lesion, which relieved her symptoms and was advised to seek further medical attention from the Department of Oncology and Department of Radiotherapy.

LESSONS

PAS can be easily misdiagnosed as PE. If a diagnosis of PE is made, but anticoagulation or even thrombolytic therapy proves ineffective, and there is no presence of PE causative factors such as deep vein thrombosis in the lower extremities, or D-dimer levels are not high, one should be cautious and consider the possibility of PAS.

Results of surgical treatment of pulmonary artery sarcomas: Does histology affect survival?

Background

In this study, we aimed to describe our experience with primary pulmonary artery sarcoma in patients who underwent pulmonary endarterectomy and to evaluate clinical features, treatment, outcomes, and survival rates according to the histological subtypes of this malignant disease.

Methods

Between March 2011 and May 2022, a total of 13 patients (7 males, 6 females; mean age: 52.6±13.0 years; range, 30 to 69 years) who underwent pulmonary endarterectomy and diagnosed with a pulmonary artery sarcoma were retrospectively analyzed. The diagnosis was confirmed histopathologically in all patients. Data including demographics, clinical characteristics, intra- and postoperative complications, length of hospital stay, morbidity, mortality, and short-term and long-term outcomes were recorded. Operative mortality was defined as death in the hospital or within 30 days of surgery.

Results

Mortality was observed in one patient due to massive hemoptysis. Morbidity developed in two patients due to acute respiratory distress. Pulmonary vascular resistance improved significantly from 508 dyn/s/cm-5 to 191 dyn/s/cm-5 (p<0.004). All patients received chemotherapy following surgery. Median followup was 14 months. Median survival for the entire series was 18 months. One-year and three-year survival rates were 60.6% and 30.3%, respectively. Median survival for leiomyosarcomas (n=6) was seven months, while it was 44 months for intimal sarcomas (p=0.004). Three-year survival was 66.7% for intimal sarcomas and 0% for leiomyosarcomas.

Conclusion

Pulmonary artery sarcoma may mimic chronic thromboembolic pulmonary hypertension. Patients with a suspected diagnosis of pulmonary artery sarcoma should be referred to expert pulmonary endarterectomy centers for surgery where a multidisciplinary team is available. Pulmonary endarterectomy has both diagnostic and therapeutic value and may improve survival and quality of life. Patients with intimal sarcoma have longer survival compared to those with leiomyosarcoma.

[Intimal pulmonary sarcoma: A case report of a rare differential diagnosis of chronic thromboembolic pulmonary hypertension]

Pulmonary angiosarcoma is a rare and malignant disease of the blood vessels. Initially, it can be misdiagnosed as chronic thromboembolic hypertension (CTEPH). In CTEPH, there is increased pressure and resistance of the pulmonary arteries following persistent obstruction of pulmonary circulation from (recurrent) thromboembolism despite adequate anticoagulative treatment.A 76-year-old patient was referred to our centre for pulmonary hypertension after a central, left-sided, subacute pulmonary thromboembolism had been observed 7 months earlier. It was treated with apixaban, but the patient described persistent dyspnoea and cough. We observed severely reduced diffusion capacity, ineffective ventilation during cardiopulmonary exercise testing and right heart strain on echocardiograph, signs that are in agreement with suspected CTEPH. Computer tomography of the chest showed a persistent, size-constant obliteration of the left main pulmonary artery, and ventilation perfusion scan confirmed complete interruption of perfusion. We suspected malignancy; PET-CT scan confirmed metabolically active lesions. Histopathological examination of a sample obtained from the lesion by endobronchial ultrasound-guided needle aspiration showed a sarcomatous tumour with amplification of the MDM2-gene. We diagnosed an intimal angiosarcoma of the left pulmonary artery and referred the patient to pneumectomy.Angiosarcoma of the pulmonary arteries is a rare differential diagnosis of persistent thrombotic lesion and suspected CTEPH. In 2015 there were less than 300 cases described.Pulmonary angiosarcoma should be considered if: lesion occupies the entire lumen of pulmonary arteries with dilatation, contrast enhancement and infiltration of the wall in radiological examination, FDG-PET CT reveals metabolically active lesions, no pulmonary thromboembolism was documented in the anamnesis, increase in size is seen despite anticoagulation, patient presents with B symptoms.Diagnosis confirmed by biopsy, resection of tumour and removal of metastases is the therapeutic standard. Median survival remains poor. Further research is needed for improved diagnosis and treatment.

68 Ga-FAPI-04 Versus 18 F-FDG PET/CT in a Case With Intimal Sarcoma of the Pulmonary Artery

ABSTRACT

Intimal sarcoma of the pulmonary artery is a rare entity, mimicking acute or chronic pulmonary thromboembolism. We describe 68 Ga-FAPI-04 and 18 F-FDG PET/CT findings in a case with intimal sarcoma of the pulmonary artery. The intrapulmonary artery tumor showed inhomogeneously increased FDG and FAPI uptake. Compared with FDG PET/CT, FAPI PET/CT more clearly delineated the tumor partially because of a very low background FAPI activity in the walls of the main pulmonary artery and right ventricle, which showed diffuse FDG uptake.

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.

Pitfalls in the imaging of pulmonary embolism

Pulmonary embolism (PE) can present with a wide spectrum of clinical symptoms that can overlap considerably with other cardiovascular diseases. To avoid PE related morbidity and mortality, it is vital to identify this disease accurately and in a timely fashion. Several clinical criteria have been developed to standardize the diagnostic approach for patients with suspected PE. Computed tomographic pulmonary angiogram has significantly improved the detection of pulmonary embolism and is considered the imaging modality of choice to diagnose this disease. However, there are several potential pitfalls associated with this modality which can make diagnosis of PE challenging. In this review, we will discuss various pitfalls routinely encountered in the diagnostic work up of patients with suspected PE, approaches to mitigate these pitfalls and incidental pulmonary embolism.

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.

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.

Pulmonary Artery Sarcoma With Low 18F-FDG Uptake

ABSTRACT

A 75-year-old man presented with dyspnea for more than 2 months, with blood test showing low platelet count and cardiac ultrasound showing severe pulmonary hypertension (>54 mm Hg). A CT pulmonary angiogram showed a filling defect in the pulmonary trunk, right and left pulmonary arteries, raising the possibilities of pulmonary embolism or artery sarcoma. FDG PET/CT was performed for further evaluation and showed low uptake in the pulmonary wall, which supported the diagnosis of pulmonary embolism. Patient was treated with anticoagulants with no changes on repeated CT pulmonary angiogram. Patient underwent surgery, and histopatological examination revealed a pulmonary artery sarcoma.

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.

Pulmonary Artery Intimal Sarcoma: A Diagnostic Challenge Using a Multimodal Approach

Pulmonary artery intimal sarcoma (PAIS) is a rare tumor without clear syndromic presentation other than nonspecific symptoms of cough, dyspnea, and weight loss. This diagnosis is difficult due to challenging radiographic interpretations of multiple imaging modalities. We present a case of a 60-year-old male, who presented to his pulmonologist and underwent a CT chest with IV contrast that initially suggested primary lung carcinoma. CT angiogram showed significant vascular filling defects suspicious of an intravascular mass, rather than vascular invasion by lung lesions. The PET/CT scans further suggested a malignant process, but indistinguishable between an extravascular or intravascular etiology. Taking these results together, they suggested an intravascular malignancy, prompting a tissue biopsy, which ultimately led to a diagnosis of PAIS with metastases. Establishing a definitive diagnosis is essential as treatment and prognosis are different for sarcoma compared to carcinoma. There is no standard treatment to date, and management often includes a multidisciplinary approach involving surgery, radiation, chemotherapy, and targeted therapy. PAIS is a rare entity that cannot be diagnosed clinically and needs a multimodality approach for its diagnosis.

Surgical treatment of primary pulmonary artery sarcoma

OBJECTIVE

Primary pulmonary artery sarcoma (PAS) is a rare tumor that originates from the intimal layer of the pulmonary artery or pulmonary valve and has a poor prognosis. The standard treatment for this devastating disease remains unclear. This study aimed to summarize the current standard treatments for PAS.

METHODS

From September 2015 to January 2020, six patients were diagnosed with PAS and underwent pulmonary endarterectomy (PEA) at our department. Their medical records were retrospectively reviewed to analyze the clinical characteristics, histopathological features, and postoperative outcomes. Fourteen articles, each reporting at least 6 cases, identified 201 patients diagnosed with PAS, and 158 patients had detailed treatments and follow-up data.

RESULTS

All of the patients who successfully underwent PEA were alive at follow-up, with a mean survival duration of 11.6 months (7-28 months), and one patient developed recurrence in the right upper lobe lung. Two patients received postoperative chemotherapy. In one patient, the tumor invaded the pulmonary valve.

CONCLUSIONS

PAS resection combined with PEA via the aid of cardiopulmonary bypass and deep hypothermic circulatory arrest could achieve maximal tumor resection in patients without metastatic lesions. An individualized surgery strategy relies on a precise preoperative imaging examination. Moreover, postoperative adjuvant therapy could yield improved survival outcomes.

Primary pulmonary artery sarcoma in the pediatric patient: Review of literature and a case report

Primary pulmonary artery sarcoma (PAS) is extremely rare in children. Nevertheless, distinguishing primary PAS from pulmonary embolism is critical to a child's survival. Primary PAS is commonly misdiagnosed as a pulmonary embolism due to similar presenting symptoms and radiographic findings. However, compared to adults, pulmonary embolism is rare in children, especially in patients who do not have predisposing factors or hypercoagulable state. We present a child with primary PAS which mimicked pulmonary embolism on presentation but eventually was resected and is doing well 5 years after resection. In the absence of predisposing factors or hypercoagulable state, solid tumors such as primary PAS should be considered when assessing a pediatric patient with presumed pulmonary embolism.

Non-small-cell Carcinoma Localised within the Pulmonary Artery Misdiagnosed as Pulmonary Thromboembolism

In this case report we describe a 69-year-old male ex-smoker with non-small-cell carcinoma localised within the pulmonary artery, misdiagnosed as pulmonary thromboembolism. This case indicates that non-small-cell carcinoma can be localised within the pulmonary artery. Furthermore, it emphasises the importance of performing a positron emission tomography scan and diagnostic intraluminal biopsy in unexplained lesions in the pulmonary artery to reach the proper diagnosis at the early stages of the disease. The patient is currently undergoing concurrent chemotherapy and radiation therapy.

Pulmonary artery sarcoma: Case report and review of the literature

Pulmonary artery sarcoma is a rare malignancy with poor prognosis which can be misdiagnosed as pulmonary thromboembolism. We present a case of a middle age woman who initially diagnosed with presumptive pulmonary embolism that was later found to have pulmonary artery sarcoma. Symptoms, pathology, imaging characteristics and available treatments are discussed.

Intraluminal Arterial Filling Defects Misdiagnosed as Pulmonary Emboli: What Else Could They Be?

Pulmonary artery filling defects can be observed in various pathologic processes other than pulmonary embolism, for example, nonthrombotic pulmonary embolism with biological and nonbiological materials and intrinsic pulmonary artery lesions. They have also been described in rare conditions, such as fibrosing mediastinitis and congenital absence or stenosis of pulmonary artery, and some pulmonary parenchymal and airway malignancies. Misdiagnosis is common owing to the relative rarity of these conditions. Correct diagnosis is based on the appropriate clinical suspicion considering the unique clinical features, laboratory findings, and additional radiologic clues inferring a pathology other than pulmonary embolism.

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

To determine the value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in differentiating malignancy of pulmonary artery (PA) from pulmonary thromboembolism (PTE) based on a larger number of cases by pooling our cases and those from the literature. Consecutive patients with a PA lesion who had undergone ¹⁸F-FDG PET/CT in our hospital were retrospectively reviewed. Moreover, PubMed, Embase, and Medline were searched for literature reporting individual maximum standardised uptake value (SUV_max) of the malignant PA lesion and/or PTE. ¹⁸F-FDG activity was compared between PA malignancy and PTE by pooling the data from literature and our patients. Receiver operating characteristic curve analysis was performed to determine the ability of SUV_max to differentiate PA malignancy from PTE. From our database, we identified 11 patients with pulmonary artery sarcoma (PAS), and nine cases of PTE. Fifty patients with a malignant PA lesion (40 cases of PAS and 10 cases of tumor embolism) and 22 subjects with PTE were extracted from the literature. In our cases, the SUV_max of PAS (11.1 ± 4.9, range: 5.5-19.9) was significantly higher than that of PTE (1.9 ± 0.6, range: 1.1-3.2; P < 0.001). There was no significant difference in the SUV_max between the literature data and our cases in malignant lesions or in PTE. Based on the pooled analysis of the literature data and our cases (61 cases of malignant lesions and 31 cases of PTE), the area under the curve for SUV_max to differentiate PA malignancy from PTE was 0.996 (95% CI: 0.989-1.000). At a cutoff value of 3.3, the sensitivity, specificity, and accuracy were 98.4%, 96.8%, and 97.8%, respectively. The ¹⁸F-FDG uptake value is an accurate index for determining PA malignancy.

Tumoral pulmonary hypertension

Tumoral pulmonary hypertension (PH) comprises a variety of subtypes in patients with a current or previous malignancy. Tumoral PH principally includes the tumour-related pulmonary microvascular conditions pulmonary tumour microembolism and pulmonary tumour thrombotic microangiopathy. These inter-related conditions are frequently found inpost mortemspecimens but are notoriously difficult to diagnoseante mortem. The outlook for patients remains extremely poor although there is some emerging evidence that pulmonary vasodilators and anti-inflammatory approaches may improve survival. Tumoral PH also includes pulmonary macroembolism and tumours that involve the proximal pulmonary vasculature, such as angiosarcoma; both may mimic pulmonary embolism and chronic thromboembolic PH. Finally, tumoral PH may develop in response to treatments of an underlying malignancy. There is increasing interest in pulmonary arterial hypertension induced by tyrosine kinase inhibitors, such as dasatanib. In addition, radiotherapy and chemotherapeutic agents such as mitomycin-C can cause pulmonary veno-occlusive disease. Tumoral PH should be considered in any patient presenting with unexplained PH, especially if it is poorly responsive to standard approaches or there is a history of malignancy. This article will describe subtypes of tumoral PH, their pathophysiology, investigation and management options in turn.

Chronic thromboembolic pulmonary hypertension (CTEPH): Updated Recommendations from the Cologne Consensus Conference 2018

Chronic thromboembolic pulmonary hypertension (CTEPH) is a subgroup of pulmonary hypertension that differs from all other forms of PH in terms of its pathophysiology, patient characteristics and treatment. For implementation of the European Guidelines on Diagnosis and Treatment of Pulmonary Hypertension in Germany, the Cologne Consensus Conference 2016 was held and last updated in spring of 2018. One of the working groups was dedicated to CTEPH, practical and controversial issues were commented and updated. In every patient with suspected PH, CTEPH or chronic thromboembolic disease (CTED, i.e. symptomatic residual vasculopathy without pulmonary hypertension) should be excluded. Primary treatment is surgical pulmonary endarterectomy (PEA) in a multidisciplinary CTEPH centre. Inoperable patients or patients with persistent or recurrent CTEPH after PEA are candidates for targeted drug therapy. There is increasing experience with balloon pulmonary angioplasty (BPA) for inoperable patients; this option, like PEA, is reserved for specialised centres with expertise in this treatment method.

[Pulmonary tumor thrombotic microangiopathy]

Pulmonary tumor thrombotic microangiopathy syndrome is a rare clinicopathological entity in which tumor cell micro-emboli in the pulmonary microcirculation induced thrombotic microangiopathy. This can cause respiratory failure, and acute or sub-acute right heart failure. Histological features include micro tumor emboli in the small arteries and arterioles of the lung associated with thrombus formation and fibro-cellular and fibro-muscular intimal proliferation. The diagnosis is however extremely difficult to make before death. Thus, most of the observations reported are based on autopsy data. Very rare diagnostic observations made before death suggest the potential effectiveness of chemotherapy. Many details remain to be elucidated, interdisciplinary research is a priority with close collaboration between pathologists and clinicians to better understand this, often fatal, syndrome. It may be that the use of targeted therapies will improve the very poor prognosis allowing survival of several weeks or months after diagnosis.

Clinical features and surgical outcomes of pulmonary artery sarcoma

OBJECTIVE

Pulmonary artery sarcoma is an exceedingly rare malignancy. There is a lack of consensus regarding its diagnosis and treatment. We reviewed our experience in the surgical management of pulmonary artery sarcoma over an 11-year period.

METHODS

From January 2005 to February 2016, 12 patients with pulmonary artery sarcoma (age 51 ± 14 years, 5 male) underwent surgical treatment at our center. Nine patients (75%) exhibited pulmonary trunk involvement on computed tomography angiography. Six patients (50%) were initially misdiagnosed with pulmonary embolism.

RESULTS

Ten patients underwent pulmonary endarterectomy, and 3 of these patients required additional unilateral pneumonectomy. The remaining 2 patients underwent exploratory thoracotomy. One patient (8.3%) died in the hospital. The median length of postoperative intensive care unit and hospital stay were 1 day (range, 1-15 days) and 8 days (range, 5-21 days), respectively. The median postoperative survival of the total series was 18 months. Patients who received postoperative combined chemo- and radiotherapy were associated with improved survival compared with those who had isolated adjuvant therapy or surgery alone (median survival 28 vs 8 months, P = .042).

CONCLUSIONS

Although pulmonary artery sarcoma has a very poor prognosis, surgical treatment offers a chance for symptom relief and better long-term outcome. Aggressive postoperative adjuvant treatment may be necessary to improve survival.

Disease- and Treatment-related Complication on F-18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Oncology Practice: A Pictorial Review

F-18-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is routinely performed in oncology patients for various indications including staging, restaging, recurrence detection, and treatment response evaluation. Many disease- and treatment-related complications can be incidentally detected on PET/CT, which may be due to the complication of radiotherapy, chemotherapy, intervention, or primary tumor itself. Some of these complications could be life threatening and need urgent intervention. Therefore, these incidental findings should be recognized on PET/CT and immediately informed to the treating physicians if required urgent intervention.

Pulmonary artery sarcoma mimicking pulmonary embolism: a case series

BACKGROUND

Pulmonary artery sarcoma (PAS) is a rare malignant neoplasm with an aggressive behavior and often difficult to distinguish from pulmonary thromboembolic disease.

AIM

To assess the demographic, clinical, and radiological characteristics of PAS and clinical course.

DESIGN AND METHODS

We retrospectively identified and analyzed all patients with PAS seen at Mayo Clinic in Rochester, Minnesota, between January 1, 1996 and July 31, 2015.

RESULTS

Of nine patients (5 women and 4 men; median age 55 years [range, 24-74 years]), eight were diagnosed while alive with surgical ( n  = 6) or catheter-based endovascular biopsy ( n  = 2); the remaining patient was diagnosed at postmortem examination. All tumors manifested on CT as filling defect in the main, right or left pulmonary artery and were not associated with peripheral filling defects in seven patients. Seven patients were initially treated with anticoagulant therapy for presumed PE; two patients were suspected to have tumor based on constrictive or expanding effect seen on CT. Five patients died after a mean duration of 2.1 years (10 months-4.25 years) after diagnosis. Two patients are alive with recurrence and metastases of the disease 23 and 27 months after diagnosis, respectively; one remaining patient is alive and disease-free 116 months after diagnosis.

CONCLUSIONS

Although PAS is associated with a poor prognosis, long-term survival is possible and can be improved by early diagnosis and prompt surgical resection. Atypical appearance on CT including central mass-like lesion without peripheral emboli and constrictive or expanding effect should raise suspicion of PAS.

Diagnosis of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is the only potentially curable form of pulmonary hypertension. Rapid and accurate diagnosis is pivotal for successful treatment. Clinical signs and symptoms can be nonspecific and risk factors such as history of venous thromboembolism may not always be present. Echocardiography is the recommended first diagnostic step. Cardiopulmonary exercise testing is a complementary tool that can help to identify patients with milder abnormalities and chronic thromboembolic disease, triggering the need for further investigation. Ventilation/perfusion (V'/Q') scintigraphy is the imaging methodology of choice to exclude CTEPH. Single photon emission computed tomography V'/Q' is gaining popularity over planar imaging. Assessment of pulmonary haemodynamics by right heart catheterisation is mandatory, although there is increasing interest in noninvasive haemodynamic evaluation. Despite the status of digital subtraction angiography as the gold standard, techniques such as computed tomography (CT) and magnetic resonance imaging are increasingly used for characterising the pulmonary vasculature and assessment of operability. Promising new tools include dual-energy CT, combination of rotational angiography and cone beam CT, and positron emission tomography. These innovative procedures not only minimise misdiagnosis, but also provide additional vascular information relevant to treatment planning. Further research is needed to determine how these modalities will fit into the diagnostic algorithm for CTEPH.

CT pulmonary angiography of adult pulmonary vascular diseases: Technical considerations and interpretive pitfalls

Computed tomography pulmonary angiography (CTPA) has become the primary imaging modality for evaluating the pulmonary arteries. Although pulmonary embolism is the primary indication for CTPA, various pulmonary vascular abnormalities can be detected in adults. Knowledge of these disease entities and understanding technical pitfalls that can occur when performing CTPA are essential to enable accurate diagnosis and allow timely management. This review will cover a spectrum of acquired abnormalities including pulmonary embolism due to thrombus and foreign bodies, primary and metastatic tumor involving the pulmonary arteries, pulmonary hypertension, as well as pulmonary artery aneurysms and stenoses. Additionally, methods to overcome technical pitfalls and interventional treatment options will be addressed.

Pulmonary Artery Sarcoma Detected on 18F-FDG PET/CT With Unusual Findings

A 32-year-old woman, who presented with "sharp pain" in the right chest for more than 1 month and worsening dyspnea and fever for 10 days, was initially thought to have a pulmonary embolism. Cardiac ultrasound showed an ill-defined echogenic mass within the pulmonary trunk. F-FDG PET/CT was performed for further evaluation. PET/CT showed an intense hypermetabolism in the main, bilateral proximal, and the right main pulmonary arteries, suggesting the presence of a malignant lesion. Biopsy confirmed the lesion as a primary pulmonary artery sarcoma.

[Angiosarcoma mimicking recurrent pulmonary embolism]

INTRODUCTION

Pulmonary artery sarcoma is a rare disease with non-specific symptoms. The clinical and radiological presentation can mimic pulmonary embolism with chronic thromboembolic pulmonary hypertension. Management is essentially surgical but the prognosis remains poor.

CASE REPORT

A patient presented with symptoms of pulmonary embolism. Despite vitamin K antagonist therapy, he suffered from extension of the endovascular defects and his pulmonary hypertension increased. Suspicious results of positron emission tomography suggested the diagnosis of pulmonary artery sarcoma that was confirmed by surgery. However, the outcome was unfavourable, leading to death of the patient.

CONCLUSION

This case reinforces the idea that the clinical and tomodensitometric presentations of pulmonary arterial sarcoma and chronic thromboembolic pulmonary hypertension are similar. The positron emission tomography seems to be a key to distinguishing these two diagnoses.

Use of endobronchial ultrasound to evaluate nonthrombotic endovascular lesions in pulmonary arteries: a systematic review

BACKGROUND

The finding of a filling defect in a pulmonary artery (PA) sometimes raises the possibility of cancer. Endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration (TBNA) may confirm the underlying nature of the endovascular lesion. However, little is known about the use of this procedure for this purpose.

METHODS

We searched PubMed and abstracts of major international conferences.

RESULTS

There was a total of 12 cases: 8 female, 3 male, and 1 unknown. The median (range) age was 60 (51 to 79) years. EBUS was performed to evaluate mass-like lesion involving the PA (n=5), persistent or progressive filling defects in the PA despite anticoagulation (n=3), filling defect in the PA with multiple areas of consolidation, air-fluid levels in the lung (n=1), and hilar density (n=1). Moreover, an endovascular lesion was incidentally noted in the PA during EBUS for evaluating lymph nodes (n=2). EBUS-TBNA was diagnostic in 9 of the 10 cases in which it was performed. The final diagnoses were: sarcoma (n=6), lung cancer (n=2), thyroid cancer (n=1), renal cell cancer (n=1), melanoma (n=1), and pulmonary embolism (n=1). The cancer was a recurrence in 6 of the 7 cases with a known history of cancer.

CONCLUSIONS

EBUS should be considered as a possible method for evaluating endovascular lesions when PA sarcoma or tumor macroembolism is suspected.

Pulmonary tumor embolism derived from stomach cancer observation with serial 18F-FDG PET/CT

Stomach cancer is one of malignancies that may result in pulmonary tumor embolism. Pulmonary tumor embolism commonly presents with dyspnea and cor pulmonale signs. We report serial observations of pulmonary tumor embolism with 18F-FDG PET/CT. 18F-FDG PET/CT scan showed chronological changes of FDG uptake in both lung fields.

A rare cause of postoperative hypotension

A 62-year-old woman presented with a 3-month history of abdominal distension and decreased exercise tolerance. A chest radiograph showed a probable left pleural effusion (Fig 1). A CT scan of the abdomen revealed a solid ovarian mass with omental caking and a large volume of ascites; there was also confirmation of a left pleural effusion. Three days before surgery a CT pulmonary angiogram (CTPA) showed no evidence of pulmonary thromboembolism (PTE). The patient had some improvement in her symptoms after paracentesis and thoracentesis with drainage of 2,000 mL and 250 mL of fluid, respectively. She underwent total abdominal hysterectomy, bilateral oophorectomy, and partial sigmoid resection with an estimated blood loss of 850 mL. During the operation, she received 5 L of crystalloid and required phenylephrine at 40 to 80 μg/min to maintain a mean arterial pressure &gt; 65 mm Hg. She was extubated after surgery, but immediately after extubation, she became markedly hypotensive and hypoxemic with a BP of 50/20 mm Hg and an oxygen saturation of 70%. An ECG showed T-wave inversions from V1 to V5 and an S1Q3T3 pattern (Fig 2). A bedside echocardiogram showed an enlarged right ventricle (RV), septal dyskinesia, and obliteration of the left ventricle, all consistent with systolic and diastolic RV overload (Fig 3).

Presentation and management of pulmonary artery sarcoma

BACKGROUND

Pulmonary artery sarcoma (PAS) is a rare but aggressive malignancy that leads to heart failure and death without treatment. Here we reviewed the presentation and management of patients treated at a national centre for pulmonary endarterectomy (PEA) and its associated hospital in Cambridge, UK.

METHODS

Details of PAS patients treated at Papworth and Addenbrooke's Hospitals between 2000 and 2014 were reviewed.

RESULTS

Twenty patients were diagnosed with PAS (11 males, 9 females), with a median age of presentation of 57 years (range 27-77). Presenting symptoms include dyspnoea (20), chest pain/tightness (7), oedema (5), constitutional symptoms (5), cough (3) and haemoptysis (3). Twelve patients were in group III/IV of the NYHA functional classification of symptoms. Initial CT scans were suggestive of thromboembolism in seven patients. Histological findings were of intimal sarcoma (13) and high grade sarcoma NOS (6). Median overall survival (OS) was 17 months. Fourteen patients underwent PEA to relieve vascular obstruction, while six had inoperable and/or metastatic disease. There were three peri-operative deaths. Although there was no difference in median OS between patients who had PEA and those who did not (20 vs 17 months, P = 0.2488), surgery provided significant symptomatic improvement and some with long-term survival. Five patients received post-surgical chemotherapy (anthracycline +/- ifosfamide), and after completion four also had radiotherapy. Patients who received post-operative chemo- and radio-therapy showed a trend towards better survival compared to those who had surgery alone (24 vs 8 months, P = 0.3417). For palliative chemotherapy, partial responses were observed with the VID regimen and pegylated liposomal doxorubicin. Stable disease was achieved in a patient with intimal sarcoma with rhabdomyosarcomatous differentiation on third-line cisplatin and topotecan. The longest surviving patient (102 months) has had PEA, adjuvant epirubicin and radiotherapy. She developed lung metastases 7 years later, which were treated with radiofrequency ablation.

CONCLUSIONS

PAS often presents with symptoms mimicking pulmonary hypertension, heart failure or thromboembolic disease. PEA provides good symptomatic relief and in some cases, offers a chance of long-term survival. Although outcome appears to be better when PEA is combined with post-operative chemo- and radio-therapy, further studies are warranted.

Spindle cell sarcoma of pulmonary artery mimicking thromboembolism with lung metastasis detected in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography

Pulmonary artery sarcoma (PAS), although rare, must be considered in the differential diagnosis of pulmonary thromboembolism (PTE). This tumor is highly malignant and the prognosis is very poor. As much as the standardized uptake values (SUVs) at fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) have helped in differentiating between benign and malignant tumors, visualization of a low-attenuation filling defect within a pulmonary artery on contrast-enhanced chest computed tomography (CT) can be suggestive of a malignancy, such as PAS, if the lesion shows high FDG uptake at PET. We present a case of PAS that showed high FDG uptake on integrated FDG PET/CT and with lung metastasis. Patient underwent endoscopic bronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA), which confirmed spindle cell sarcoma.

The incidence of pulmonary embolism and associated FDG-PET findings in IV contrast-enhanced PET/CT

RATIONALE AND OBJECTIVES

Most fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography with computed tomography (PET/CT) studies are performed on cancer patients. These patients are at increased risk of pulmonary embolism (PE). In this retrospective review, we determined the rate of PE, and the prevalence of associated FDG-PET findings on intravenous (IV) contrast-enhanced PET/CT.

MATERIALS AND METHODS

We identified all PET/CT studies performed at our institution with a reported finding of PE between January 2005 and October 2012. The medical record was reviewed for symptoms, which were identified after the diagnosis of PE, and whether the patients received treatment. The prevalence of associated FDG-PET findings was determined.

RESULTS

A total of 65 total cases of PE (of 182,72 total PET/CT examinations) were identified of which 59 were previously unknown. This gives an incidental PE (IPE) rate of 0.32%. Of the patients where sufficient clinical information was available, 34 of 36 (94%) were treated either with therapeutic anticoagulation or inferior vena cava filter, and 30 of 36 (83%) were asymptomatic in retrospect. Of the patients with IPE, we found nine (15.2%) with associated focal pulmonary artery hypermetabolism, three (5.1%) with hypermetabolic pulmonary infarction, and one with increased isolated right ventricular FDG uptake (1.7%). One case of chronic PE demonstrated a focal hypometabolic filling defect in a pulmonary artery on PET.

CONCLUSIONS

We found IPE in 0.32% of PET/CT scans. Focal pulmonary artery hypermetabolism or hypometabolism, and hypermetabolic pulmonary artery infarction with the "rim sign" were uncommonly associated with PE. These findings could raise the possibility of IPE in non-IV contrast-enhanced PET/CT studies.