Aim: To understand the challenges associated with diagnosis and management of pulmonary adenocarcinoma in pregnancy. Background: Lung cancer during pregnancy is a rare condition and most of the patients are diagnosed in advanced stages, thus have adverse outcomes even after treatment. Management of such cases pose a singular challenge to the treating doctors. Case report: We are reporting a case of in vitro fertilization (IVF) conceived 38-year-old female with dichorionic diamniotic twin pregnancy, who was diagnosed with adenocarcinoma lung stage IV at 22 weeks of pregnancy. Ultrasound of thorax revealed right-sided pleural effusion with underlying lung collapse. Cytological examination of pleural fluid and pleural biopsy revealed adenocarcinoma. Computed tomography (CT) scan of the spine showed small lytic lesion in the D10 vertebral body. Magnetic resonance imaging (MRI) abdomen, MRI brain and ultrasound neck was negative for metastasis. The patient received targeted chemotherapy in form of oral gefitinib throughout pregnancy. Elective cesarean section was performed at 34 weeks of pregnancy, and targeted therapy was continued after delivery. Patient responded well to the management. Conclusion: Pulmonary adenocarcinoma in pregnancy is a challenging clinical situation to diagnose and manage. Early stage diagnosis and individualised management is the key to success. As there is limited data on use of targeted therapy in pregnancy, further trials and research is needed. Clinical significance: Pulmonary adenocarcinoma in pregnancy is a life-threatening condition with aggressive behavior and high mortality rates. It is of utmost importance to be thorough with the emerging trends in its diagnosis and management.