Mesenchymal Tumors of the Lung

The mesenchymal tumors of the lung consist of a variety of neoplasms that originate from cells of mesenchymal origin, including endothelium, muscle, fibroblasts, cartilage/bone. The tumors with these pathologic features are most commonly seen in the lung as metastatic lesions from sarcomas elsewhere in the body. However, there are examples of primary mesenchymal tumors in the lung that are important to recognize. The most important of these are listed below. Of note, lymphangioleiomyomatosis was previously considered an interstitial lung disease, but most recent studies have shown it to be a neoplasm arising from the perivascular epithelioid cells (PECs) of the lung and is appropriately included in this chapter.