Abstract Introduction Pulmonary neuroendocrine tumors (NETs) represent 1%-2% of all primary lung malignancies and about 25%-30% of all NETs, with the lung being the second most common site after the gastrointestinal tract. Atypical carcinoid tumors comprise 10%-15% of pulmonary carcinoids and are characterized by a less aggressive behavior than the other non-small cell lung cancers, with a post-resection recurrence rate of 26%. Case report A 68-year-old woman who was a lifelong smoker with no respiratory symptoms presented with an 8-mm non-calcified nodule in the right lower lobe as an incidental finding during a computed tomography (CT) scan of the abdomen. Imaging surveillance of the nodule was recommended, and subsequent CT scans showed that the nodule grew to 10 mm over 2 years. The patient underwent CT-guided biopsy, and pathological analysis of the biopsy specimen confirmed an atypical neuroendocrine carcinoma. The patient underwent a right video-assisted thoracoscopic surgery for right lower lobectomy with lymph node dissection. No additional treatment was recommended for the stage IA tumor. After 9 years of follow-up, repeat imaging revealed multiple pleural nodules in the right hemithorax, which showed increased fluorodeoxyglucose uptake on positron emission tomography. A diagnostic pleuroscopy revealed multiple nodules in the middle aspect of the anterior and posterior parietal pleura (Image 1 below with yellow arrows pointing to the pleural nodules). Biopsy confirmed a metastatic atypical neuroendocrine carcinoma. Image 2 shows a metastatic intermediate-grade neuroendocrine carcinoma to the pleura, characterized by an organoid growth pattern with rosette formation. The patient is currently managed with observation only. Discussion Atypical carcinoids have higher recurrence rates than typical carcinoids, and usually involve the liver, lung, or lymph nodes, while pleural dissemination, as in our case, is extremely rare (5%). Most recurrences occur more than 5 years after initial resection, underscoring the need for long-term surveillance beyond 10 years. Complete surgical resection remains the mainstay of treatment, with adjuvant therapy offering limited benefit. Prognosis depends on tumor grade, nodal status, and stage, with five-year survival rates of approximately 90% for typical and 60% for atypical carcinoids. Approximately 80% of pulmonary NETs are centrally within the lung, while 20% arise in peripheral regions. This case highlights the potential for late, atypical recurrence and the importance of extended postoperative follow-up. This abstract is funded by: None
Umashankar et al. (Fri,) studied this question.