(Refer to the PDQ summary on adult Breast Cancer Treatment for more information.)
Primary lung tumors are rare in children and histologically quite diverse. When epithelial cancers of the lung occur, they tend to be of advanced stage with prognosis dependent on both histology and stage.
The majority of pulmonary malignant neoplasms in children are due to metastatic disease, with an approximate ratio of primary malignant tumors to metastatic disease of 1:5. While primary pulmonary tumors are rare in children, the majority of these tumors are malignant. In a review of 383 primary pulmonary neoplasms in children, 76% were malignant and 24% were benign. These tumors may respond to the ALK inhibitor crizotinib in the presence of ALK translocations.[Level of evidence: 3iiiDiv]
The most common malignant primary tumors of the lung, bronchial tumors and pleuropulmonary blastoma, are discussed below.
Bronchial tumors are a heterogeneous group of primary endobronchial lesions, and although adenoma implies a benign process, all varieties of bronchial tumors on occasion display a malignant behavior. There are three histologic types:[23,24,25,26,27,28]
- Carcinoid tumor (most frequent). Carcinoid tumors account for 80% to 85% of all bronchial tumors in children.[23,24,25,26,27]
- Mucoepidermoid carcinoma.
- Adenoid cystic carcinoma (least frequent).
Bronchial tumors of all histologic types are associated with an excellent prognosis in children, even in the presence of local invasion.[29,30]
Clinical presentation and diagnostic evaluation
The presenting symptoms of a cough, recurrent pneumonitis, and hemoptysis are usually due to an incomplete bronchial obstruction. Because of difficulties in diagnosis, symptoms are frequently present for months, and, occasionally, children with wheezing have been treated for asthma with delays in diagnosis as long as 4 to 5 years.
Metastatic lesions are reported in approximately 6% of carcinoid tumors, and recurrences are reported in 2% of cases. Atypical carcinoid tumors are rare but more aggressive with 50% of patients presenting with metastatic disease at diagnosis.[19,32] There is a single report of a child with a carcinoid tumor and metastatic disease who developed the classic carcinoid syndrome. Octreotide nuclear scans may demonstrate uptake of radioactivity by the tumor or lymph nodes, suggesting metastatic spread.
The management of bronchial tumors is somewhat controversial because bronchial tumors are usually visible endoscopically. Biopsy of these lesions may be hazardous because of hemorrhage, and endoscopic resection is not recommended. Bronchography or computed tomography scan may be helpful to determine the degree of bronchiectasis distal to the obstruction since the degree of pulmonary destruction may influence surgical therapy.
Conservative pulmonary resection, including sleeve segmental resection, when feasible, with the removal of the involved lymphatics, is the treatment of choice.[35,36] Adenoid cystic carcinomas (cylindroma) have a tendency to spread submucosally, and late local recurrence or dissemination has been reported. In addition to en bloc resection with hilar lymphadenectomy, a frozen section examination of the bronchial margins should be performed in children with this lesion. Neither chemotherapy nor radiation therapy is indicated for bronchial tumors, unless evidence of metastasis is documented.