Chapter 085. Neoplasms of the Lung (Part 18)

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Bronchial Adenomas Bronchial adenomas (80% are central) are slow-growing endobronchial lesions; they represent 50% of all benign pulmonary neoplasms. About 80–90% are carcinoids, 10–15% are adenocystic tumors (or cylindromas), and 2–3% are mucoepidermoid tumors. Adenomas present in patients 15–60 years old (average age 45) as endobronchial lesions and are often symptomatic for several years. Patients may have a chronic cough, recurrent hemoptysis, or obstruction with atelectasis, lobar collapse, or pneumonitis and abscess formation. Bronchial adenomas of all types, because of their endobronchial and often central location, are usually visible by fiberoptic bronchoscopy. Because they are hypervascular, they can bleed profusely...

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Chapter 085. Neoplasms of the Lung (Part 18) Bronchial Adenomas Bronchial adenomas (80% are central) are slow-growing endobronchial lesions; they represent 50% of all benign pulmonary neoplasms. About 80–90% are carcinoids, 10–15% are adenocystic tumors (or cylindromas), and 2–3% are mucoepidermoid tumors. Adenomas present in patients 15–60 years old (average age 45) as endobronchial lesions and are often symptomatic for several years. Patients may have a chronic cough, recurrent hemoptysis, or obstruction with atelectasis, lobar collapse, or pneumonitis and abscess formation. Bronchial adenomas of all types, because of their endobronchial and often central location, are usually visible by fiberoptic bronchoscopy. Because they are hypervascular, they can bleed profusely after bronchoscopic biopsy, and this problem should be anticipated. Bronchial adenomas must be considered as potentially malignant, thus requiring removal for symptom relief and because they
can be locally invasive or recurrent, potentially can metastasize, and may produce paraneoplastic syndromes. Surgical excision is the primary treatment for all types of bronchial adenomas. The extent of surgery is determined at operation and should be as conservative as possible. Often bronchotomy with local excision, sleeve resection, segmental resection, or lobectomy is sufficient. Five-year survival rate after surgical resection is 95%, decreasing to 70% if regional nodes are involved. The treatment of metastatic pulmonary carcinoids is unclear because they can either be indolent or behave more like SCLC (Chap. 344). Assessment of the tempo and histology of the disease in the individual patient is necessary to determine if and when chemotherapy or radiotherapy is indicated. Carcinoid and Other Neuroendocrine Lung Tumors Neuroendocrine lung tumors represent a spectrum of pathologic entities, including typical carcinoid, atypical carcinoid, and large cell neuroendocrine cancer, as well as SCLC. SCLC and large cell neuroendocrine cancer are high- grade neuroendocrine tumors and in general should be treated as described for SCLC. By contrast, typical carcinoid and atypical carcinoids are low- and intermediate-grade tumors with different treatment approaches and in general are resistant to chemotherapy (Chap. 44). Carcinoids, like SCLCs, may secrete other hormones, such as ACTH or AVP, and can cause paraneoplastic syndromes that resolve on resection. Uncommonly, bronchial carcinoid metastases (usually to the liver) may produce the carcinoid syndrome, with cutaneous flush,
bronchoconstriction, diarrhea, and cardiac valvular lesions, which SCLC does not do. Carcinoid tumors that have an unusually aggressive histologic appearance (referred to as atypical carcinoids) metastasize in 70% of cases to regional nodes, liver, or bone, compared with only a 5% rate of metastasis for carcinoids with typical histology. Large cell neuroendocrine cancer is a high-grade NSCLC with neuroendocrine features. These tumors are characterized by histologic features similar to small cell cancer, but they are formed by larger cells. The prognosis for patients with large cell neuroendocrine cancer is significantly worse than that for patients with atypical carcinoid and classic large cell cancer. Five-year survival is 21% for patients with large cell neuroendocrine cancer, 65% for atypical carcinoid, and 90% for typical carcinoid. Thymomas See Chap. e12. Hamartomas Pulmonary hamartomas have a peak incidence at age 60 and are more frequent in men than in women. Histologically, they contain normal pulmonary tissue components (smooth muscle and collagen) in a disorganized fashion. They are usually peripheral, clinically silent, and benign in their behavior. Unless the radiographic findings are pathognomonic for hamartoma, with "popcorn"
calcification, the lesions usually have to be resected for diagnosis, particularly if the patient is a smoker. VATS may minimize the surgical complications. Metastatic Pulmonary Tumors The lung is a frequent site of metastases from primary cancers outside the lung. Usually such metastatic disease is incurable. However, two special situations should be borne in mind. The first is the development of an SPN or a mass on chest x-ray in a patient known to have an extrathoracic neoplasm. This nodule may represent a metastasis or a new primary lung cancer. Because the natural history of lung cancer is often worse than that of other primary tumors, a single pulmonary nodule in a patient with a known extrathoracic tumor is approached as though the nodule is a primary lung cancer, particularly if the patient is >35 years and a smoker. If a vigorous search for other sites of active cancer proves negative, the nodule is surgically resected. Second, in some cases multiple metastatic pulmonary nodules can be resected with curative intent. This tactic is usually recommended if, after careful staging, it is found that (1) the patient can tolerate the contemplated pulmonary resection, (2) the primary tumor has been definitively and successfully treated (disease-free for >1 year), and (3) all known metastatic disease can be encompassed by the projected pulmonary resection. Patients with uncontrolled primary tumors and other extrapulmonary metastases are not considered. Primary tumors whose pulmonary metastases have been successfully resected for cure include osteogenic and soft tissue sarcomas; colon, rectal,
uterine, cervix, and corpus tumors; head and neck, breast, testis, and salivary gland cancer; melanoma; and bladder and kidney tumors. Five-year survival rates of 20– 30% have been found in selected series, and dramatic results have been achieved in patients with osteogenic sarcomas, where resection of pulmonary metastases (sometimes requiring several thoracotomies) is a standard curative treatment approach.