Other Primary Neoplasms of the Pleura
All primary neoplasms of the pleura are very rare. As noted in Chap. 1, DMM is the most frequent primary neoplasm of the pleura and only about 2,000 new cases occur per year in the USA. Other primary neoplasms of the pleura may be unfamiliar to the surgeon and pathologist because of the infrequency with which they are encountered, making diagnosis challenging. Since some of these neoplasms are benign or borderline and, even when malignant, are localized, they are often treated and may be cured by complete surgical excision. Therefore, it is often important to differentiate these exceedingly rare neoplasms at frozen section from processes that may not be treatable by resection, including DMM and metastatic cancers on the one hand and reactive or inflammatory diseases on the other.