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Bronchogenic carcinoma represents the overwhelming majority of pulmonary neoplasms. However, a great variety of tumors originate in the lung.1 Benign neoplasms (Table 117-1) comprise less than 1% of all resected lung tumors and nonbronchogenic primary pulmonary malignancies (Table 117-2) account for 3% to 5% of all lung tumors. Numerous classifications of these rare tumors have been devised, though none are widely accepted. Due to the disparate histogenesis of these varied tumors, it is best to discuss them individually.
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A broad array of benign primary lung tumors has been recognized, as discussed below.
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Mucus gland adenoma, also known as bronchial cystadenoma, is a benign epithelial tumor that originates in the bronchial submucus glands and presents as an exophytic endobronchial mass.2 Mucus gland adenoma occurs in adults and children and has no gender predilection.3 The tumor occurs in the segmental or lobar bronchi and symptoms are due to obstruction or hemorrhage. Histologically, mucus-filled acini are lined with well-differentiated mucus-secreting cells, without any evidence of invasion. Radiographically, mucus gland adenomas appear as coin lesions on chest radiograph, or with an “air-meniscus” sign on CT scan. Treatment is endoscopic local excision. However, lobectomy may be required if the distal lung is destroyed.
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Tracheal papillomatosis, a form of recurrent respiratory papillomatosis (RRP), occurs in both children and adults.4 When symptomatic, patients can present with dyspnea, cough, hemoptysis, and symptoms simulating reactive airway disease.5 Histologically, papillomas consist of stratified squamous epithelium with a fibrovascular core. Imaging studies demonstrate lesions within the trachea and bronchi. Bronchoscopy is the diagnostic modality of choice. Squamous metaplasia and malignant transformation occur in 0.3% to0.5% of patients with RRP and have been linked to radiation ...