Spatial Tumor Heterogeneity in a Young Female with Lung Adenocarcinoma and Brain Metastasis

Small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) are the two different forms of lung cancer, the latter subtype accounts for approximately 85% of cases. Lung cancer is estimated to be the main cause of all cancer deaths, accounting for nearly 1,800,000 deaths globally in 2020. In this clinical case, we describe a female patient with non-specific symptoms over an approximate duration of one and a half years. Metastatic lung adenocarcinoma was diagnosed after the onset of severe neurological symptoms, brain surgery, and historical analysis of the large pathological brain mass. Following this, the tumor in the lung, which was small in size and the sole metabolically active site of the disease, was surgically removed. The recurrence in the brain and the onset of new neurological symptoms occurred rapidly—within three months, necessitating a second operation. Histological examination of the primary tumor and metastasis unveiled significant disparities–the primary tumor was moderately differentiated with PD-L1 expression (programmed death-ligand 1) within the range of 1 to 49%, while metastasis was poorly differentiated and PD-L1 negative, both absent of EGFR mutations (epidermal growth factor receptor) and ALK fusion (anaplastic lymphoma kinase). Following two brain operations, the patient underwent three-dimensional conformal radiation therapy (3DCRT). Subsequently, the initiation of systemic therapy was postponed by a two-month interval due to the activation of chronic hepatitis C virus infection. This case study contributes to the growing body of knowledge aimed at enhancing our grasp of tumor heterogeneity and dynamics of progression.