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Pediatric pulmonary neoplasms are a manifold group of tumors, typically distinct from those of adults. They are characterized by their rare occurrence and generally nonspecific presenting symptoms. This combination of features may lead to delayed diagnosis. Pediatric patients with pulmonary neoplasms may be asymptomatic or present with nebulous respiratory symptoms that are also associated with substantially more prevalent non-neoplastic pulmonary processes, such as reactive airway disease, upper and lower respiratory infections, and aspirated foreign body. In fact, non-neoplastic pulmonary disease occurs 60- and 12-fold more frequently than primary pulmonary tumors and pulmonary metastases, respectively.1 In the United States, the average annual incidence of pediatric primary malignant pulmonary tumors is 16 cases.2 Therefore, the most critical factor in diagnosing pulmonary malignancy is a high index of suspicion, especially when symptoms persist despite adherence to treatment strategies. For example, presumed asthma refractory to standard therapies or presumed respiratory infection that lingers with appropriate antimicrobial agents must lead to consideration of an underlying pulmonary neoplasm. Because of this diagnostic challenge, definitive histopathologic diagnosis is often delayed until unabating symptoms prompt further evaluation. After diagnosis and staging, surgery is a mainstay of treatment. Prognosis depends on underlying tumor type: Estimated 5-year survival ranges from 0% with adenocarcinoma to greater than 90% with mucoepidermoid carcinoma and certain benign lesions.2,3
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GENERAL CONSIDERATIONS
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Presentation/Evaluation
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Children and infants with pulmonary neoplasms present with a diverse set of symptoms. On one side of the spectrum, between 7% and 21% of patients undergo resection for asymptomatic, incidentally discovered pulmonary tumors.4,5 On the other extreme, children may present in extremis with hemorrhage from tumor invasion or cardiopulmonary insult from parenchymal or mediastinal compression. The majority of patients, however, present with unrelenting or recurrent nonspecific constitutional or respiratory symptoms such as fever, cough, wheezing, or dyspnea.5 Repeated pneumonias or atelectasis of the same parenchymal distribution should equally raise concern.
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Given the heterogeneity of pulmonary tumors, symptoms correspond to tumor size, number of lesions, behavior (i.e., grade and malignant potential), anatomic location, involvement of adjacent organs, and degree of vascularity.6 One recent study of children and infants with primary lung tumors documented how symptomaticity varied with tumor type, with findings occurring for 30%, 30%, 0%, and 15% of patients with inflammatory myofibroblastic tumors (IMTs), pleuropulmonary blastoma, carcinoid tumors, and other tumors, respectively.5 Pediatric patients diagnosed with lung metastases are asymptomatic up to 70% of the time7 because these lesions are generally small, peripheral, and discovered on surveillance studies. However, children with primary pulmonary malignancies are generally more likely to present with symptoms. Historic estimates suggest that between 0% and 6% of children with such tumors were asymptomatic upon presentation,3,4 whereas one more contemporary series includes an asymptomatic proportion of 24% among children with primary pulmonary malignancies.5 This latter statistic may be elevated ...