Abstract Introduction Low-dose computed tomography (CT) screening has improved early detection of lung cancer; however, interpretation and surveillance of sub-centimeter pulmonary nodules remain challenging. Although most small nodules are benign or indolent, a subset may represent aggressive malignancies that progress rapidly despite adherence to recommended follow-up intervals. This case highlights such a diagnostic dilemma and raises questions about whether current surveillance algorithms adequately capture high-risk individuals. Case Presentation A 73-year-old male with a history of coronary artery disease, former tobacco use, and prior Agent Orange exposure was admitted after a fall resulting in a right hip fracture. He underwent surgical repair and was subsequently transferred to an inpatient rehabilitation facility. During rehabilitation, he developed new-onset dyspnea. CT angiography revealed multiple pulmonary emboli with right heart strain and a sub-centimeter right middle-lobe pulmonary nodule. Repeat chest CT in three months for surveillance was recommended. He was transferred for thromboembolectomy and discharged. Three months later, the patient presented to the emergency department with severe dyspnea and was admitted to index hospitalization with acute hypoxemic respiratory failure. Repeat CT chest demonstrated a large loculated right pleural effusion, mass-like consolidation in the right upper lobe with airway occlusion, and mediastinal and hilar lymphadenopathy as well as innumerous hepatic lesions concerning for metastatic disease (Figure 1). His hospital course was complicated by a large right hemothorax requiring emergent chest tube placement and atrial fibrillation with subsequent shock. Pleural fluid cytology and liver biopsy confirmed metastatic small cell lung carcinoma, positive synaptophysin, CD56 and TTF-1, with a Ki-67 proliferative index 90%. Despite treatment, he experienced progressive decline and transitioned to hospice. Figure 1: CT chest demonstrating right middle lobe mass and pleural effusion. Discussion This case underscores the potential for rapidly progressive small cell carcinoma to evade timely detection under standard screening protocols. Current Fleischner Society guidelines recommend three month CT follow-up or PET-CT for solitary nodules in high-risk patients; however, sub-centimeter lesions often preclude biopsy or reliable PET characterization. In patients with significant risk factors - such as smoking and Agent Orange exposure, more aggressive surveillance strategies or earlier functional imaging may warrant consideration. Further study is needed to define optimal management of indeterminate nodules in ultra-high-risk cohorts. Conclusion Even with adherence to guideline-recommended follow up, sub-centimeter pulmonary nodules may represent highly aggressive malignancies capable of rapid disseminations. This case emphasizes the need for individualized surveillance intervals and refinement of current lung cancer screening protocols. This abstract is funded by: None
Singh et al. (Fri,) studied this question.