US EPA

7436469 

Journal Article 

Mechanisms of Tumor Dissemination in Thoracic Neoplasms 

Locatelli, F; Ambrosi, F; Rossi, G; , 

2020 

1-33 

10.1007/978-3-030-27233-3_1 

http://link.springer.com/10.1007/978-3-030-27233-3_1
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The thorax, and the lung in particular, is a frequent site of primary malignancy from different cell lines and the most common target of metastatic spread due to the high density of the vascular bed. The histopathologic diagnosis of thoracic findings is straightforward in the vast majority of cases and supported by clinical history of a known primary tumor elsewhere and imaging findings. However, the type of neoplastic dissemination may arise some doubts in the differential diagnosis between primary and secondary malignancies. Indeed, the histopathologic appearance of some metastatic tumors mimics primary malignancy (e.g., lepidic growth pattern), while primary lesions may disseminate as metastatic disease (e.g., lung adenocarcinoma with miliary pattern). More recently, the old concept of aerogenous spread of tumor cell in primary lung cancer has regained attention under the alternative robe of “spread through airspaces (STAS)” and emerged as a phenomenon associated with prognostic value in all adenocarcinoma histology, squamous cell carcinoma, and neuroendocrine carcinomas. Finally, several benign/low-grade neoplasms may lead to pulmonary metastatic dissemination.