Molecular and immunohistochemical analysis with clinical pathological correlation for lung mucinous carcinoma

Abstract

Invasive lung mucinous adenocarcinoma (IMC) is a rare disease with unique pathological features and uncommon biological manifestations. These tumors may show the same heterogeneous combination of acinar, papillary, lepidic pattern as seen in non-mucinous tumors. The distinction between IMC and metastatic mucinous carcinoma of other sites is difficult by routine histology. In this study, molecular and immunohistochemical analysis with clinical correlation of 15 IMC cases will be studied. The results showed that IMC was associated with male smokers and showed a phenotype of CK7+, TTF-1+, CK20+, Napsin A+, CDX2- and CK5/6-. TTF-1 positivity suggests that in the context of differentiating IMC from other mucinous tumors metastatic to the lung, evaluation of TTF-1 may have limited diagnostic utility. The molecular profile for IMC showed EGFR- (80%) and KRAS+ (33.3%) which is inconsistent with previous studies suggesting a larger sample size is needed. Hence, more research (e.g. FISH) is required to provide a better diagnosis for IMC.