Fact-sheet: Pulmonary artery sarcoma


Updated on 11/15/2024 at 5:43 PM

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Definition

Primary pulmonary artery sarcomas are rare malignant tumors that arise from mesenchymal cells of the pulmonary artery intima.

Clinical features

Symptoms are often nonspecific, mimicking pulmonary embolism:

  • Dyspnea (72%)
  • Chest pain (45%)
  • Cough (42%)
  • Hemoptysis (24%)
  • Weight loss (21%)
  • Syncope (9%) in advanced cases.

Sarcoma should be suspected in the absence of peripheral phlebitis, in cases of hemothorax, and especially if the patient worsens under anticoagulant therapy.

Radiography

Chest radiography may be normal.

Suggestive but nonspecific findings:

  • Unilateral enlargement of a pulmonary hilum
  • Hilar or perihilar mass
  • Cardiomegaly
  • Reduced vascularity of a pulmonary field
  • Pulmonary nodules associated with ipsilateral hilar enlargement.

Ultrasound

Echocardiography may show:

  • Valvular location of the tumor
  • Tumor extension into the right ventricle
  • Dilation of the right heart chambers
  • Pulmonary arterial hypertension on Doppler.

TEE allows better visualization of the pulmonary artery trunk and may show:

  • An endoluminal hyperechoic or heterogeneous tissue process
  • Irregular thickening of the arterial wall.

CT

Pulmonary CT angiography is the study of choice. It allows:

  • Detection of the sarcoma
  • Exclusion of pulmonary embolism
  • Precise staging.

CT findings supporting the diagnosis:

  • Massive, unilateral pulmonary arterial obstruction (less than 1% of pulmonary emboli)
  • Polylobulated obstructive process, of soft tissue density, with a branching distribution, attaching to the arterial wall at an acute angle.
  • Mediastinal lymphadenopathy, parenchymal infiltration.
  • Transmural and exovascular extension of the lesion.
  • Contrast enhancement after injection.
  • Metastatic pulmonary nodules.
  • No regression, or even worsening, of the mass despite anticoagulant therapy.

MRI

MRI is an effective technique for differentiating a sarcoma from a thrombus.

MRI findings suggestive of the diagnosis:

  • Intraluminal soft tissue mass: Intermediate signal intensity, increased peripherally on T1
  • Inhomogeneous, hyperintense signal on T2 (hemorrhage or necrosis)
  • Significant enhancement after gadolinium injection.
  • Unilateral obstruction, transmural and exovascular extension, lobulated contours, acute-angle interface with the arterial wall.

Vascular intervention

X-Ray Angiography is increasingly less used for diagnostic purposes. It may show a polylobulated filling defect with irregular contours extending into the branches of the pulmonary artery or the right heart. However, this appearance is not specific, and a to-and-fro motion on cine-angiography would be more suggestive.

Nuclear medicine

Ventilation-perfusion lung scintigraphy lacks specificity. A complete, unilateral perfusion defect, unusual in pulmonary embolism, may be observed. The lack of change in perfusion defects despite anticoagulation is suggestive of tumoral obstruction.

PET-CT: a tumoral process is hypermetabolic, unlike a thrombus.

Management

  • Confirm the diagnosis with pathological examination of a biopsy.
  • Discuss management in a multidisciplinary team meeting.
  • Consider surgical resection if feasible.

Classification

Pulmonary artery sarcomas can be classified according to their histologic type:

  • Leiomyosarcoma (approximately 25%)
  • Fibrosarcoma (16%)
  • Angiosarcoma (5.8%)
  • Rhabdomyosarcoma (4%)
  • Malignant fibrous histiocytoma (4%) (now termed undifferentiated pleomorphic sarcoma)
  • Osteogenic sarcoma
  • Chondrosarcoma (4%)
  • Liposarcoma
  • Undifferentiated sarcoma (majority of cases)

Differential diagnosis

  • Acute pulmonary thromboembolism
  • Pulmonary artery stenosis
  • Pulmonary arteritis