Intimal sarcoma of the pulmonary artery with unusual findings: a case report

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.

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.

Pulmonary artery sarcoma: an unexpected settler in the right ventricular outflow tract

Pulmonary artery sarcoma (PAS) is a sporadic malignant tumor that mainly originates from the pulmonary arteries. However, PAS may also involve the right ventricular outflow tract (RVOT) and lead to obstruction, syncope, or sudden death. Early diagnosis and complete surgical resection are essential to prolong survival and improve the quality of life of patients with PAS. Herein, we report a case of a young female patient admitted for pulmonary malignancy and acute pulmonary embolism. The patient had a mass in the RVOT, which was detected by transthoracic echocardiography. Computed tomography and magnetic resonance imaging revealed the invasion depth and extent of the lesions. Surgical resection improved hemodynamics, while pathological and immunohistochemical tests confirmed the diagnosis of a pulmonary artery sarcoma. Local recurrence was detected in the adjacent tissues about two months after the surgery. Given the potential risk of reoperation, the patient was suggested to undergo conservative 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.

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.>.

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.

Intimal sarcoma of the pulmonary artery without 18F-fluorodeoxyglucose uptake

Primary pulmonary intimal sarcoma is rare. Differentiating it from pulmonary thromboembolism is difficult because of similarities in clinical symptoms and imaging findings. Positron-emission tomography-computed tomography has been useful for diagnosing primary pulmonary intimal sarcoma. We describe a rare case of primary pulmonary intimal sarcoma that showed no abnormal ¹⁸F-fluorodeoxyglucose uptake on positron-emission tomography. We resected the mass and performed right ventricular outflow tract reconstruction. Proper diagnosis is necessary to determine appropriate therapy, Clinicians must consider the possibility of primary pulmonary intimal sarcoma even if imaging findings are inconsistent with the disease.

A comprehensive review on the diagnosis and management of intimal sarcoma of the pulmonary artery

Only a few hundred cases of intimal sarcomas of pulmonary artery (ISPA) were reported on the literature. Diagnosis of this rare entity is a challenging dilemma with the need for a high expertise in the radiological and pathological identification of ISPA. Treatment strategies rely initially on an early aggressive surgery aiming for complete surgical resection with clear margins while no clear recommendations guiding the choice for additional drug therapy or radiotherapy exist. In this article, we perform an extensive review of the literature on ISPA with details on the clinical presentation, diagnosis and management strategies. An additional goal of this paper is to make practicing oncologists aware of this rare entity with clear idea on the initial management.

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.

Multiple skeletal muscle metastases revealing a cardiac intimal sarcoma

We report the case of a 59-year-old female with progressive bilateral painful swelling of the thighs. MRI revealed multiple intramuscular necrotic masses with similar morphologic patterns. Whole-body CT and 18-FDG PET-CT scans demonstrated additional hypermetabolic muscular masses and a lobulated lesion within the left atrial cavity. As biopsy of a muscular mass was compatible with a poorly differentiated sarcoma with MDM2 oncogene amplification, two diagnoses were discussed: a dedifferentiated liposarcoma with muscle and heart metastases or a primary cardiac sarcoma, mainly a cardiac intimal sarcoma, with muscular metastases, which was finally confirmed by array-comparative genomic hybridization (aCGH) in a sarcoma reference center. This case emphasizes the potential for intimal sarcoma to disseminate in skeletal muscle prior to any other organ and the need for a genomic approach in addition to classical radiopathologic analyses to distinguish primary from secondary locations facing simultaneous tumors of the heart and skeletal muscles with MDM2 amplification.

Multimodal Approach of Pulmonary Artery Intimal Sarcoma: A Single-Institution Experience

Introduction

Pulmonary artery sarcoma (PAS) is a rare tumor, whose therapeutic approach is mainly based on surgery, either pneumonectomy or pulmonary endarterectomy (PEA). The prognosis reported in published series is very poor, with survival of 1.5 months without any kind of treatment.

Patients and Methods

From January 2010 to January 2016, 1027 patients were referred to our hospital for symptoms of acute or chronic pulmonary thromboembolic disease. Twelve patients having a confirmed diagnosis of PAS underwent PEA. Median age was 64.5 years. Most patients had a long history of symptoms, having a median time of 7.5 months from onset of symptoms to surgery.

Results

Following PEA and cardiopulmonary rehabilitation, 10 patients received conventional chemotherapy with doxorubicin and ifosfamide, starting at a median of 42 days from surgery. Four patients also received radiotherapy. Four patients have died due to disease progression, while 7 are still alive, with 5 being disease-free at 4–55+ months from diagnosis.

Conclusions

In patients with PAS, a multimodal approach including PEA, CT, and RT is feasible but it should be evaluated individually, according to the tumor extension and the patient's clinical condition. Apart from improving quality of life mainly by reducing or delaying symptoms due to PH, it may improve life expectancy.

An intimal sarcoma of pulmonary artery mimicking pulmonary embolism: a case report and literature review

Pulmonary artery intimal sarcoma is a highly aggressive disease, and is most often misdiagnosed as pulmonary thromboembolism (PTE) due to the similar clinical symptoms and its rarity, which leads to the use of inappropriate treatments such as prolonged anticoagulant therapy. We reported a case of pulmonary artery intimal sarcoma in a patient who was misdiagnosed as having PTE. Pathology after surgery confirmed malignant disease. We concluded that when a patient presents with mild clinical manifestations yet with strong imaging manifestations, pulmonary artery malignancy should be suspected.

Pulmonary Artery Intimal Sarcoma: A Case Report

Pulmonary artery intimal sarcomas are rare and lethal malignant tumors that typically affect larger vessels: the aorta, inferior vena cava, and pulmonary arteries. Since symptoms and imaging of pulmonary arterial intimal sarcomas mimic pulmonary thromboembolism, the differential diagnosis of a patient presenting with chest pain, dyspnea, and filling defect within the pulmonary arteries should include intimal sarcoma. Often right ventricular failure is observed due to pulmonary hypertension caused by the obstructive effect of the tumor and concomitant chronic thromboembolism. We report the case of a 72-year-old African-American male with arterial intimal sarcoma of the left and right pulmonary artery with extension through the right artery into the bronchus and right lung.

A case of pulmonary artery sarcoma presented as cavitary pulmonary lesions

Pulmonary artery sarcoma (PAS) is a rare, poorly differentiated malignancy arising from the intimal layer of the pulmonary artery. Contrast-enhanced chest computed tomography (CT) is a good diagnostic modality that shows a low-attenuation filling defect of the pulmonary artery in PAS patients. An 18-year-old man was referred to our hospital for the evaluation and management of cavitary pulmonary lesions that did not respond to treatment. A contrast-enhanced CT of the chest was performed, which showed a filling defect within the right interlobar pulmonary artery. The patient underwent a curative right pneumonectomy after confirmation of PAS. Although lung parenchymal lesions of PAS are generally nonspecific, it can be presented as cavities indicate pulmonary infarcts. Clinicians must consider the possibility of PAS as well as pulmonary thromboembolism in patients with pulmonary infarcts. So, we report the case with PAS that was diagnosed during the evaluation of cavitary pulmonary lesions and reviewed the literatures.

Pulmonary artery intimal sarcoma: poor 18F-fluorodeoxyglucose uptake in positron emission computed tomography

Intimal sarcoma of the pulmonary artery is a rare malignant tumor that may be misdiagnosed as chronic pulmonary thromboembolism, even if various imaging techniques are used. We report a case of a 58-year-old man with pulmonary artery intimal sarcoma.18F-fleuorodeoxyglucose (FDG) uptake was poor in the mass of the pulmonary artery, and no other hypermetabolic lesions were noted elsewhere. Our presumptive diagnosis was a massive mural thrombus and a concomitant chronic thromboembolism. Intravenous heparin and recombinant human tissue-type plasminogen activator was subsequently administered. However, the patient needed an emergency operation for sudden aggravation of the vital signs, and the tissue diagnosis was intimal sarcoma with poor clinical outcomes.