C80-48 From Cavity to Carcinoma: The Importance of Vigilant Follow-up in Cavitary Lung Lesions

Abstract Introduction Lung cancer is the leading cause of cancer mortality in the US. Early diagnosis and treatment remain crucially important in preventing lung cancer-related deaths. There is substantial evidence that cavitary or cystic lung lesions are frequently misinterpreted as benign or infectious processes, leading to delayed diagnosis of lung cancer. A systematic review estimated that cystic airspace-associated lung cancers constitute up to one-fourth of delayed radiological diagnoses. Case Presentation A 40-year-old woman presented to the emergency department with cough and fatigue. Two weeks earlier, she had been evaluated at an urgent care clinic and diagnosed with influenza. ED evaluation revealed leukocytosis, and imaging showed a large cavitary lesion in the left lower lobe. She was diagnosed with a secondary bacterial infection and lung abscess and treated with intravenous antibiotics. Additional workup, including AFB smear and fungal serologies, was negative, though rheumatoid factor was positive. She improved clinically and was discharged with rheumatology follow-up, where the lesion was not felt to represent a rheumatoid nodule. After one month of amoxicillin–clavulanate, her symptoms improved but repeat CT showed no radiographic change. At her pulmonology follow-up the decision was made to pursue malignancy workup, despite her being lifelong non-smoker with no personal or family history of malignancy. She underwent EBUS-TBNA and navigational bronchoscopy, which revealed mucinous adenocarcinoma. Discussion Cavitary lung lesions present a broad differential, including infectious, inflammatory, and malignant etiologies. While infection is often the most likely cause, especially in younger or otherwise low-risk patients, our case underscores the importance of maintaining a high index of suspicion for malignancy. Lung cancer can occasionally manifest as cavitary disease, and delayed recognition may lead to progression before diagnosis. Recent studies have identified an alarming trend of young, non-smoking women of color presenting with advanced disease and higher inpatient mortality, suggesting that traditional risk stratification may overlook vulnerable populations. This highlights the need for individualized diagnostic strategies, vigilant imaging follow-up, and further research into non-tobacco-related carcinogenic pathways. Early tissue diagnosis remains crucial to avoid missed or delayed cancer detection, even in patients whose clinical presentation appears consistent with infection. This abstract is funded by: None