A rare case of mesothelioma showing micropapillary and small cell differentiation with aggressive behavior.

Pleural mesothelioma is a rare neoplasm and roughly 70% are the epithelioid type, which is characterized by proliferation of epithelioid tumor cells with a tubulopapillary growth pattern [1]. There have been few reports of mesothelioma having a micropapillary pattern [2] and a small cell component [3]. To the best of our knowledge, there has been no previously reported case containing both micropapillary and small cell components. Herein, we report a rare case of mesothelioma with micropapillary component and small cell differentiation exhibiting aggressive behavior in a 59-year-old woman.