Localized Fibrous Tumor
Formerly believed to be mesotheliomas, localized or solitary fibrous tumors (LFTs) are rare tumors, most common in the pleura but also reported to involve the lung and other parts of the body. Patients with LFTs are usually middle aged but the overall age distribution is wide. Digital clubbing and pleural effusions may be seen. Their size is quite variable ranging from 1 to 2 cm to masses filling an entire hemithorax. This variation in size can be reflected in their radiographic appearance. Tumors larger than 10 cm may behave in a malignant fashion. Calcification occurs in a minority of the cases. Rarely, an LFT will grow into an airway and in those instances it will mimic a tumor of endobronchial or endotracheal origin. Microscopically, a hemangiopericytoma-like pattern and a cellular pattern may co-exist along with the more common “pattern-less” pattern. Fine needle aspirates show scant to variable cellularity, fragments of ropy collagen, and oval to spindly cells with bland-looking oval to round nuclei.