Squamous Cell Carcinoma Diagnosed by Bronchoscopy Presenting as a Regressing Abnormal Chest Opacity Initially Considered Mucoid Impaction: A Case Report

We report a case of an 80-year-old woman who was incidentally found to have an abnormal chest opacity in the absence of any symptoms. Chest computed tomography demonstrated a slight tendency toward interval regression, leading to an initial suspicion of mucoid impaction. However, bronchoscopy was subsequently performed, and a diagnosis of squamous cell carcinoma was established. In patients without symptoms, it may be difficult to exclude lung cancer based solely on imaging findings, even when a lesion shows a regressive course.