Not like breast cancer, but like breast cancer: micrometastasis and micropapillary structure in lung cancer

Micropapillary growth pattern is characterized, as morphologic features of small tight clusters of tumor cells floating in clear spaces. Initially, aggressive nature of this pattern has been reported in bladder, prostate and breast cancer (1), and included in lung cancer classification subsequently. The growth pattern is commonly admixed with other growth patterns, and micropapillary pattern is seen only a part of the tumor.