EGFR T790M-Positive Lung Adenocarcinoma Metastases to thePituitary Gland Causing Adrenal Insufficiency: A Case Report

A 64-year-old man, with history of micropapillary thyroid cancer and epidermal growth factor receptor-positive lungadenocarcinoma with no evidence of active disease for 3 years after chemotherapy and radiation on erlotinib, presented withfatigue, nausea, lack of appetite, and xeroderma. A screening magnetic resonance image of the patient’s head demonstrated anew bilateral pituitary mass. Initial evaluation revealed low morning cortisol, and the patient was diagnosed with adrenalinsufficiency. His symptoms rapidly improved with maintenance glucocorticoids. Soon thereafter, the patient developed anacute visual deficit secondary to enlargement of the pituitary mass, and biopsy revealed EGFR T790M positive metastaticlung adenocarcinoma. Hence, we present a rare case of metastatic lung adenocarcinoma to the pituitary causing secondaryadrenal insufficiency