Not always embolism: A case of pulmonary artery intimal sarcoma - The role of the radiologist in early diagnosis.

Introduction: Pulmonary artery intimal sarcoma (PAIS) is a rare malignant neoplasm with imaging features that can mimic pulmonary embolism (PE). It must be recognized early because a radical resection may be useful to prolong survival. Case description: A clinical case of a 57-year-old Caucasian male affected by PAIS is presented, which describes the computed tomography (CT) findings found in PAIS and the elements of overlap and differentiation with PE. The main common element is represented by the endoluminal filling defect of the pulmonary arterial vessels in contrast-enhanced CT examinations; a characteristic polypoid morphology or polylobulated contours are typical findings of PAIS. Other specific elements of the neoplasm such as wall eclipse sign, extension beyond the arterial wall, and metastasis are also explained. Conclusions: The overlap of the clinical-radiological findings and the epidemiological difference between PAIS and PE cause a diagnostic delay. By knowing the differential elements, the radiologist can detect the neoplasm early to accelerate diagnosis and suggest optimal management.