Neuroendocrine tumors of the bronchi are rare, slow-growing tumors arising from bronchial mucosa; they affect patients in their 40s to 60s. Approximately half of patients are asymptomatic, and symptomatic patients most commonly present with cough, hemoptysis, wheezing, dyspnea, chest pain, and recurrent pneumonia; paraneoplastic syndromes are less common. Diagnosis is by chest imaging (CT and PET-CT with gallium DOTATATE) and bronchoscopic biopsy. Treatment is based on surgery, sometimes with additional chemoradiation.
Neuroendocrine tumors develop from neuroendocrine cells in the gastrointestinal tract or the pancreas (approximately 65%), pulmonary bronchi or thymus (less than 30%), and the remainder from the genitourinary tract (1, 2). Although these neuroendocrine tumors are often benign or only locally invasive, those affecting the bronchus are frequently malignant. Some neuroendocrine tumors are endocrinologically active; the likelihood varies by site of origin and is highest for tumors originating in the ileum and proximal colon and lower with neuroendocrine tumors originating in the lungs.
General references
1. Cueto A, Burigana F, Nicolini A, Lugnani F. Neuroendocrine tumors of the lung: hystological classification, diagnosis, traditional and new therapeutic approaches. Curr Med Chem. 2014;21(9):1107-1116. doi:10.2174/0929867321666131129125953
2. National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines). Neuroendocrine and Adrenal Tumors, version 3.2025. https://nccn.org/guidelines/category_1. Accessed November 7, 2025.
Symptoms and Signs of Neuroendocrine Lung Tumors
Up to 50% of patients with neuroendocrine lung tumors are asymptomatic (1). Patients are often incidentally diagnosed when imaging is obtained for another purpose. The most common presenting symptoms are those of airway obstruction, including dyspnea, wheezing, and cough, which often leads to a misdiagnosis of asthma. Recurrent pneumonia, hemoptysis, and chest pain are also common.
Paraneoplastic syndromes, including Cushing syndrome due to ectopic adrenocorticotropic hormone (ACTH) may occur in 2 to 6% of patients (1). Acromegaly due to ectopic growth hormone–releasing factor and gastrinoma (Zollinger-Ellison syndrome) due to ectopic gastrin production are rare.
Carcinoid syndrome occurs in approximately 2 to 12% of patients with neuroendocrine lung tumors. It is caused by the release of 5-hydroxyindoleacetic acid (a metabolite of serotonin) (1). Carcinoid syndrome symptoms include:
Flushing
Diarrhea
Bronchospasm (mimicking asthma)
Chronic sequelae of carcinoid syndrome include:
Telangiectasias
Right-sided valvular heart disease
Retroperitoneal fibrosis
A left-sided heart murmur (mitral stenosis or mitral regurgitation) due to serotonin-induced valvular damage occurs rarely with neuroendocrine lung tumors (as opposed to the right-sided valvular lesions of gastrointestinal neuroendocrine tumors).
Symptoms and signs reference
1. Granberg D, Juhlin CC, Falhammar H, Hedayati E. Lung Carcinoids: A Comprehensive Review for Clinicians. Cancers (Basel). 2023;15(22):5440. doi:10.3390/cancers15225440
Diagnosis of Neuroendocrine Lung Tumors
Bronchoscopic biopsy
CT and positron emission tomography (PET)-CT with gallium (Ga) 68 DOTATATE
Sometimes, urinary serotonin and 5-hydroxyindoleacetic acid levels (for carcinoid syndrome)
Diagnosis of these tumors is based on bronchoscopic biopsy, but evaluation often initially involves chest CT, which reveals tumor calcifications in up to one-third of patients.
PET-CT scans with Ga 68 DOTATATE are useful for determining regional and metastatic spread.
Increased urinary levels of serotonin and its metabolite 5-hydroxyindoleacetic acid support the diagnosis, but these substances are not commonly elevated.
Treatment of Neuroendocrine Lung Tumors
Surgery
Sometimes adjuvant chemotherapy and/or radiation therapy.
Treatment of neuroendocrine lung tumors is surgical removal with or without adjuvant chemotherapy and/or radiation therapy.
Prognosis depends on tumor type. In one Danish cohort, 5-year survival for well-differentiated (typical) neuroendocrine lung tumors was > 90% but was lower for atypical tumors (1).
Treatment reference
1. Rewitz KS, Grønbæk H, Tabaksblat EM, Dahl Baunwall SM, Dam G. Prognosis of Patients with Bronchopulmonary Neuroendocrine Neoplasms in a Tertiary Neuroendocrine Tumor Centre of Excellence. Neuroendocrinology. 2022;112(12):1214-1224. doi:10.1159/000525379
