Abstract
AimsPulmonary enteric adenocarcinoma (PEAC) is a rare variant of pulmonary adenocarcinoma. Due to its rarity, few pathological and molecular studies have been performed on PEAC. We herein conducted clinicopathological, immunohistochemical and molecular analyses of PEAC with a focus on its differentiation from invasive mucinous adenocarcinoma (IMA).MethodsWe examined the clinicopathological features of 16 cases of PEAC and performed a genetic analysis using next-generation sequencing (NGS). The results obtained were compared with those for IMA.ResultsThe average age of patients with PEAC (seven men and nine women) was 72.9 years. A comparison of clinical data on PEAC and IMA revealed no significant differences in age, sex or smoking history. Fifteen PEAC cases had dirty necrosis. Immunohistochemically, the positive rates for each antibody in PEAC were as follows: CK7, 88% (14/16); CK20, 81% (13/16); CDX2, 88% (14/16); p53, 69% (11/16); MUC1, 100% (16/16); MUC2, 19% (3/16); MUC5AC, 69% (11/16); MUC6, 19% (3/16). The positive rates for these antibodies in IMA were 100%, 87%, 0%, 7%, 93%, 0%, 100% and 80%, respectively.EGFRmutations, theMETexon 14 skipping mutation,BRAFmutations, theALKfusion gene andROS-1fusion gene were not detected in any cases of PEAC or IMA. Among PEAC cases, NGS identifiedKRASmutations in seven (44%, 7/16) andTP53mutations in nine (56%, 9/16). Among IMA cases, the most commonly mutated gene wasKRAS(90%).ConclusionsThe rates of dirty necrosis, immunopositivity for CDX2 andTP53mutations were significantly higher, while that ofKRASmutations was significantly lower in PEAC cases than in IMA cases.
Subject
General Medicine,Pathology and Forensic Medicine