Abstract Introduction Pulmonary neuroendocrine tumors (NETs) represent a small fraction of lung cancers, accounting for about 1 to 2% of adult cases and roughly a quarter of all NETs. Their symptoms are often vague and overlap with common respiratory illnesses, which can delay diagnosis. In patients with presumed pneumonia who do not improve despite appropriate therapy, alternative causes such as underlying malignancy should be considered. Case Presentation A 55-year-old Hispanic male with a history of chronic atrial fibrillation, hypertension, diabetes mellitus, prior cerebrovascular accident with residual right hemiparesis, and a five-pack-year smoking history presented with a 2-day history of productive cough, shortness of breath, generalized malaise, and weakness. He was started on oral levofloxacin by his primary care physician for suspected community-acquired pneumonia. Despite mild improvement, fever and dyspnea persisted, prompting hospitalization. On arrival, he appeared mildly dyspneic. The lung examination revealed diminished breath sounds over the left lung field. Chest computed tomography (Figure, Panel A) demonstrated a large mediastinal and left upper lobe mass with a left pleural effusion, raising suspicion for an underlying neoplasm. Empiric broad-spectrum intravenous antibiotics were started for presumed complicated pneumonia. Subsequent core biopsy of the mass (Figure, Panel B) confirmed a high-grade small cell neuroendocrine carcinoma. Staging studies revealed localized disease, and oncology was consulted for further management. Discussion Lung neuroendocrine tumors’ initial presentation can mimic infectious processes, making diagnosis challenging. In patients who fail to respond to standard antibiotic therapy or whose imaging reveals atypical or persistent infiltrates, clinicians should expand the differential diagnosis to include malignant etiologies. Small cell neuroendocrine carcinoma is particularly aggressive and prone to early dissemination, but timely recognition allows for earlier initiation of systemic therapy. Conclusion This case illustrates the importance of considering lung malignancy in patients with recurrent or non-resolving pneumonia, especially those with a smoking history. Maintaining diagnostic vigilance and an early multidisciplinary approach can significantly impact outcomes in these uncommon but aggressive tumors. This abstract is funded by: None
Hurtado et al. (Fri,) studied this question.