Primary lung tumors are rare in children and histologically quite diverse. Bronchial tumors are a heterogeneous group of primary endobronchial lesions, and though adenoma implies a benign process, all varieties of bronchial tumors on occasion display a malignant behavior. There are three histologic types, including the following:[14,15,16,17,18]
Carcinoid tumors account for 80% to 85% of all bronchial tumors in children.[14,15,16,17,18] Epithelial cancers of the lung are rare in children. When they do occur, they tend to be of advanced stage with prognosis dependent on both histology and stage.
The presenting symptoms are usually because of an incomplete bronchial obstruction with a cough, recurrent pneumonitis, and hemoptysis. 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 cases and recurrences occur in 2% of cases. Atypical carcinoid tumors are rare but more aggressive with 50% of patients presenting with metastatic disease at diagnosis.[19,21] 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. Bronchial tumors of all histologic types are associated with an excellent prognosis in children, even in the presence of local invasion.[23,24]
The management of bronchial tumors is somewhat controversial because bronchial tumors are usually visible endoscopically. Biopsy in 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.[26,27] 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 carried out in children with this lesion. Neither chemotherapy nor radiation therapy is indicated for bronchial tumors, unless evidence of metastasis is documented.
Pleuropulmonary blastoma (PPB) is a rare and highly aggressive pulmonary malignancy in children. PPB appears to progress through the following stages:
- Type I: A purely lung cystic neoplasm with subtle malignant changes that typically occurs in the first 2 years of life and has a good prognosis. However, there have been reports of Type I transitioning directly to Type III.[28,29]
- Type II: A cystic and solid neoplasm. Cerebral metastasis may occur in 11% of patients.
- Type III: A purely solid neoplasm.[31,32] Cerebral metastasis occurs in up to 50% of patients with Type III tumors.