Histologic Evolution From Adenocarcinoma to Squamous Cell Carcinoma After Gefitinib Treatment

• Published in: The Annals of thoracic surgery Vol. 99; no. 1; pp. 316 - 319
• Main Authors: Hsieh, Min-Shu, Jhuang, Jie-Yang, Hua, Syue-Fong, Chou, Yueh-Hung
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.01.2015
• Subjects: Adenocarcinoma - drug therapy; Adenocarcinoma - pathology; Antineoplastic Agents - adverse effects; Antineoplastic Agents - therapeutic use; Carcinoma, Squamous Cell - chemically induced; Carcinoma, Squamous Cell - pathology; Cardiothoracic Surgery; Cell Transformation, Neoplastic - chemically induced; Female; Humans; Lung Neoplasms - chemically induced; Lung Neoplasms - drug therapy; Lung Neoplasms - pathology; Middle Aged; Quinazolines - adverse effects; Quinazolines - therapeutic use; Surgery; 10
• ISSN: 0003-4975; 1552-6259; 1552-6259
• DOI: 10.1016/j.athoracsur.2014.02.075

We report two cases of lung cancer with histologic transformation from adenocarcinoma to squamous cell carcinoma after gefitinib treatment. Both cases involved advanced lung cancers, initially confirmed as adenocarcinomas with sensitive epidermal growth factor gene mutations. After gefitinib treatment, the second pathologic examination in each case revealed squamous cell carcinoma retaining identical mutations without newly acquired resistance mutations. The underlying mechanism may have been pluripotent tumor cells with divergent differentiation or mixed lung cancer including both adenocarcinomatous and squamous cell carcinomatous components. This report widens the spectrum of histologic evolution as a mechanism underlying the acquisition of drug resistance.