This case report describes the rare occurrence of a T790M resistance mutation found in a central nervous system (CNS) parenchymal metastasis. A concomitant squamous histology transformation in a lung non-T790M-resistant metastasis is also described. The authors hypothesize that this CNS resistance and histology transformation may have resulted from intermittent use of erlotinib treatment. This case report emphasizes the complexities of using erlotinib in the induction setting.
Correspondence: Kevin S. Scher, MD, MBA, Cedars-Sinai Tower Hematology Oncology Medical Group, 9090 Wilshire Blvd #200, Beverly Hills, CA 90211. E-mail: Kevin.Scher@cshs.org