Indolent Adenocarcinoma In Situ Mistaken as Aggressive during Lung Cancer Screening Program: To Heal or to Harm?

Background: Low-dose computed tomography-based lung cancer screening (LCS) has demonstrated efficacy in reducing lung cancer mortality. However, concerns about overdiagnosis and overtreatment hinder global LCS implementation. Methods: Here, we report the unique case of a slow-growing 1 cm pure ground-glass opacity (GGO) of the lung, known for 15 years, which unexpectedly developed into a 5 cm mixed GGO within 1 year, with an increased solid component and FDG-PET uptake. Results: The patient, asymptomatic, underwent right upper lobectomy and lymphadenectomy, even complicated with postoperative chylothorax, later revealing to be affected by only an unchanged adenocarcinoma in situ (AIS). Conclusions: This case serves as a reminder of the potential behavior of pre-invasive lesions, which can mimic invasive neoplasia and may lead to overtreatment, and underscores the challenge of distinguishing indolent lesions from potentially aggressive malignancies in LCS, highlighting the need for the ongoing refinement of LCS protocols to mitigate this risk.