Introduction: Primary lung angiosarcoma is a rare malignancy of vascular origin and difficult diagnosis.It entails a poor prognosis and high mortality rate.Here we present the case of a primary lung angiosarcoma with multifocal compromise which presented itself as a spontaneous pneumothorax.Case Presentation: A 35-year-old patient presented with a 10-day history of cough and right pleuritic pain.A high-resolution thoracic CT-scan was performed, showing multiple nodules of random distribution located on the right lung, with a ground glass opacity halo and basal laminar pneumothorax, without other pathological findings.A wedge lung biopsy was performed on the anterior segment of the right upper lobe, histopathology findings showed a high-grade fusocellular neoplasm and immunohistochemistry showed positivity for CD31, FLI1 and Caldesmon.The patient was then diagnosed with primary lung angiosarcoma.Discussion: Angiosarcomas are vascular malignancies that can be identified by the abnormal endothelial vascular cells proliferation, they represent about 1-2% of all softtissue sarcomas.Lung angiosarcomas are rare and usually correspond to metastatic compromise, thus, primary lung angiosarcomas are even rarer, with only 39 cases reported until now.The distinction between a primary or secondary origin is challenging since they both share histopathologic and clinical characteristics, which is why it is of utmost importance to exclude extra-thoracic metastatic compromise.The clinical manifestations of primary angiosarcomas are diverse, usually symptoms develop throughout a 6-month period, being thoracic pain and hemoptysis the most common ones.Radiologically, they characterize for having multiple nodules of random distribution and variable size showing a ground glass halo around them, this halo is due to alveolar hemorrhage around the nodules.Final diagnosis is stablished through histopathological analysis, showing rounded or oval monomorphic cells with an eosinophilic nucleus, usually presenting mitosis, necrosis and hemorrhage.Furthermore, immunohistochemical analysis are needed, usually showing positivity for endothelial (CD31, CD34, VIII factor), epithelial (Cytokeratin and EMA), and vimentin markers.Due to its rareness, treatment of this pathology is not yet standardized, nevertheless it must be considered as a differential diagnosis of lung lesions showing multiple nodularity and ground glass halos.