You are in: eMedicine Specialties > Thoracic Surgery > Tumors Benign Lung TumorsArticle Last Updated: Jul 18, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Dale K Mueller, MD, Associate Professor of Surgery, Section Chief, Department of Surgery, University of Illinois at Peoria; Co-Medical Director, Thoracic Center of Excellence, Vice-Chair, Department of Cardiovascular Medicine and Surgery, OSF St Francis Medical Center Dale K Mueller is a member of the following medical societies: American College of Chest Physicians, American College of Surgeons, American Medical Association, Chicago Medical Society, Illinois State Medical Society, and Society of Thoracic Surgeons Coauthor(s): Norvin Perez, MD, Clinical Assistant Professor of Emergency Medicine, Albert Einstein College of Medicine; Consulting Staff, Department of Emergency Medicine, Montefiore Medical Center; Oluyinka S Adediji, MD, Consulting Staff, Department of Adult and General Medicine, Health Services Incorporated, Montgomery, Alabama Editors: Richard Thurer, MD, Professor, Department of Surgery, Division of Cardiothoracic Surgery, University of Miami School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Daniel S Schwartz, MD, FACS, Clinical Assistant Professor of Cardiothoracic Surgery, New York University School of Medicine; Consulting Staff, Department of Surgery, Division of Thoracic Surgery, North Shore University Hospital/Long Island Jewish Medical Center; Rajalaxmi McKenna, MD, FACP, Consulting Staff, Department of Medicine, Southwest Medical Consultants, SC, Good Samaritan Hospital, Advocate Health Systems; John Geibel, MD, DSc, MA, Professor, Department of Surgery, Section of Gastrointestinal Medicine and Department of Cellular and Molecular Physiology, Yale University School of Medicine; Director of Surgical Research, Department of Surgery, Yale-New Haven Hospital Author and Editor Disclosure Synonyms and related keywords: benign lung neoplasms, pulmonary nodules, primary lung tumors, neoplastic lesions, pneumonia, atelectasis, hemoptysis, hamartomas, bronchial adenomas, chondroadenomas, bronchial cystadenomas, mucous gland adenomas, tracheobronchial tumors, parenchymal tumors, sclerosing hemangioma INTRODUCTIONSection 2 of 11
  Solitary pulmonary nodules are found at a rate of 1-2 per 1000 chest radiographs. About 30% of these nodules prove to be malignant. Of the rest of the nodules, benign tumors of the lung make up about 2-5% of primary lung tumors. Benign lung tumors are a heterogenous group of neoplastic lesions originating from pulmonary structures. These tumors include bronchial adenomas, hamartomas, and a group of uncommon neoplasms (eg, chondromas, fibromas, lipomas, leiomyomas, hemangiomas, teratomas, pseudolymphomas, endometriosis, and bronchial glomus tumors). ProblemAlthough benign lung tumors do not pose a significant health problem, complications can result from an obstructive lesion that could predispose the patient to pneumonia, atelectasis, and hemoptysis. These tumors are considered benign, and, therefore, their malignant/cancerous potential is minimal. FrequencyBenign tumors make up 2-5% of all primary lung tumors, and slightly less than 15% of pulmonary nodules are benign lung tumors. The exact incidence is not known because these tumors are often asymptomatic and are only detected during autopsy. Reported series suggest that benign lung tumors affect men more frequently than women (adenoma and hamartoma). The age range of patients affected is 17-77 years, with a mean age of 56.2 years for all types. EtiologyThe cause of benign lung tumors is not known. PathophysiologyThe cause and pathogenesis of benign lung tumors are poorly understood. The nomenclature of benign lung tumors is based on histological findings. Some of these tumors have benign features, while others are hamartomas. Neoplastic lesions are characterized by the autonomous proliferation of cells without a response to the normal control mechanisms governing their growth. An additional characteristic of benign tumors is extension without local tissue invasion or spread to other sites. Hamartomas, on the other hand, consist of haphazardly organized mature cells and tissues. Hamartomas are composed mostly of masses of hyaline cartilage with a myxoid connective tissue, adipose cells, smooth cells, and clefts lined by respiratory epithelium. Benign lung tumors can be classified pathologically, but a clinically useful classification would combine location (ie, endobronchial or parenchymal) and information about whether the lesions are single or multiple. Benign lung tumors can also be classified by their presumed origin. Those classifications include unknown (hamartoma, clear cell, teratoma), epithelial (papilloma, polyps), mesodermal (fibroma, lipoma, leiomyoma, chondroma, granular cell tumor, sclerosing hemangioma) and other (myofibroblastic tumor, xanthoma, amyloid, mucosa-associated lymphoid tumor). Adenomas and hamartomas constitute the largest group of benign lung tumors and, thus, deserve detailed descriptions. HamartomasHamartomas (chondroadenomas) are the most common type of benign lung tumor. They mainly occur in adults but, on occasion, occur in children. Hamartomas are peripherally located. Grossly, they have a firm marblelike consistency. Histologically, hamartomas generally consist of epithelial tissue and other tissues such as fat and cartilage. Hamartomas can be easily enucleated, but wedge resection is also appropriate. Bronchial adenomasBronchial adenomas make up 50% of all benign pulmonary tumors. The term bronchial adenoma, when used loosely, includes carcinoid tumors, adenocystic carcinomas, and mucoepidermoid carcinomas, which in fact are low-grade malignant tumors. The use of the term bronchial adenoma should be discouraged because it encompasses several benign and malignant tumors. Mucous gland adenomasMucous gland adenomas are true benign bronchial adenomas. Mucous gland adenomas are also called bronchial cystadenomas, and they arise in the main or local bronchi. Histologically, they consist of columnar cell–lined cystic spaces with a papillary appearance. Other rare tumor typesTracheobronchial tumors Multiple laryngeal papillomatosis is a viral disease of the upper airway that affects children. Multiple laryngeal papillomatosis has malignant potential and may spread to the tracheobronchial tree later. Solitary papillomas usually are less than 1.5 cm in diameter. They usually are lobar or segmental in location and are histologically similar to viral papillomatosis. Inflammatory papilloma is a solitary polypoid mass of granulation tissue that is associated with an underlying pulmonary inflammatory condition. Granular cell myoblastomas are of neural cell origin. A granular cell myoblastoma contains polygonal or spindle cells with granular cytoplasm. Granular cell myoblastomas tend to be multiple in 10% of cases and are more common in men aged 30-50 years. Other parenchymal tumors occasionally occurring in the endobronchial tree (eg, leiomyoma, lipoma) almost exclusively are found at an endobronchial location. Solitary parenchymal tumors Sclerosing hemangioma is an uncommon tumor derived from the epithelial cells of pneumocytes (terminal bronchiolar cells). This tumor consists of several elements, including solid cellular areas, papillary structures, sclerotic regions, and blood-filled spaces. This tumor is most commonly found in middle-aged women. Chest radiograph shows a well-defined nodule that is less than 4 cm. Other mesenchymal tumors include lipoma, leiomyoma, neural tumors, fibroma, benign clear-cell tumor, teratoma, plasma cell granuloma, fibrous histiocytoma, xanthoma, pulmonary hyaline granuloma, pulmonary endometrioma, and pseudolymphoma. Multiple parenchymal tumors Many of these benign lung tumors may occasionally have multiple origins. Among these are hamartomas, hyalinizing granulomas, leiomyomas, and sclerosing hemangiomas. The Carney triad is a syndrome of gastric epithelioid leiomyosarcoma, pulmonary chondromas, and extra-adrenal paragangliomas. The Carney triad mainly affects women. Pulmonary tumorlets are minute collections of neuroendocrine cells scattered throughout the lung. Pulmonary tumorlets predominantly affect older women. Clinically significant intrapulmonary chemodectomas apparently are paragangliomas. They behave in a benign fashion. Multiple minute pulmonary tumors, on the other hand, are of no clinical significance. ClinicalWhen recording a patient's history, include questions related to the usual differential diagnoses and lung cancer. For example, smoking history, age, exposure to carcinogens, previous malignant tumor or lung disease, domicile, and occupational and travel history are important. The diagnostic approach is basically the same for these tumors. Clinical presentations depend upon the location of the tumor (eg, trachea, other airways, parenchyma). Hemoptysis, lung mass on chest radiograph, and unresolved infiltrates may be present. Symptoms may include pseudoasthmatic wheezing; persistent coughing; shortness of breath; hemoptysis; fever, especially when associated pneumonia is present; diminished breath sounds; dullness to percussion; and rales. If a patient is asymptomatic, the tumor may be found serendipitously and, sometimes, classified as a solitary pulmonary nodule. INDICATIONSSection 3 of 11
The purpose of surgical intervention for benign lung tumors is to avoid missing potentially malignant lesions. Otherwise, remove benign lung tumors when they are symptomatic, which indicates the presence of complications such as pneumonia, atelectasis, and/or hemoptysis. Advances in minimally invasive techniques make it less important to avoid removing a lesion which may be benign. No longer must a patient be subjected to a large incision (posterolateral thoracotomy) for the purpose of diagnosing a solitary pulmonary nodule or treating a benign lung tumor. Localized resection (wedge resection) performed with a minimally invasive technique has decreased the length of hospital stay and morbidity for patients with benign lung tumors. Bronchoscopic resection offers an alternative to surgical resection with benign endobronchial lung tumors, including carcinoid tumors. RELEVANT ANATOMYSection 4 of 11
Determination of whether a lung mass is benign or malignant based solely on its anatomical location is an incorrect practice. Anatomical location has no predictability on the malignant potential of a tumor. Benign lung tumors can occur in the periphery of the lung but can also occur as endobronchial within the tracheobronchial tree. CONTRAINDICATIONSSection 5 of 11
Perform a biopsy on lung masses in order to determine the mass malignant potential. Contraindications to a biopsy procedure are bleeding diathesis and cardiopulmonary conditions, which may place the patient's life at risk as a result of the procedure. WORKUPSection 6 of 11
Lab Studies
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Diagnostic Procedures
Histologic FindingsSee Pathophysiology. TREATMENTSection 7 of 11
Medical TherapyA solitary nodule in a young nonsmoking patient can be monitored with serial radiographs as long as the solitary nodule does not double in size in less than a year and it does not significantly increase in the pattern of calcification and shape consistent with a malignancy. Otherwise, medical therapy is limited to the initial management of complications and associated comorbidity. Surgical TherapyThe extent of surgery may be simple endoscopic resection, thoracotomy with bronchotomy/local excision, segmental resection, lobectomy, sleeve resection, or pneumonectomy. The extent is usually determined at surgery and is as conservative as possible. Endoscopic resection using the rigid bronchoscope is readily used to resect endobronchial benign lung tumors except for bronchial adenomas. Recently, bronchoscopic resection offers an alternative to surgical resection. At 1 and 10 years, respectively, 100% and 94% of completely resected carcinoids were free of disease. Commonly, surgical resection is recommended for bronchial adenomas because of the potential for malignancy. The surgical approach should include complete resection, sparing of as much lung as possible, and lymph node dissection. Endoscopic resection with neodymium:yttrium-aluminum-garnet (Nd:YAG) laser can be used for adenoma in high-risk or elderly patients. Preoperative DetailsDetermine operability and resectability and take steps to prevent or limit operative and postoperative complications. Intraoperative DetailsAnesthesia preparation is similar to that for any standard thoracotomy and involves use of an epidural, double lumen endotracheal tube, and invasive lines (including radial artery catheter and central line). Prior to double lumen placement, bronchoscopy via a standard endotracheal tube should identify any endobronchial component and plan for the surgical resection. At the time of open thoracotomy, perform a complete tumor resection and conserve as much lung as possible. In the setting of a lung adenoma, a complete lymph node dissection should also be performed. Postoperative DetailsTriage the patient to the surgical ICU or postoperative recovery floor. Follow-upWhen observation is elected as medical management, performing chest radiograph surveillance every 3 months for the first year, every 6 months the second year, and yearly thereafter is recommended. For excellent patient education resources, visit eMedicine's Procedures Center and Cancer and Tumors Center. Also, see eMedicine's patient education article Bronchoscopy and Bronchial Adenoma. COMPLICATIONSSection 8 of 11
Possible complications due to benign lung tumors include pneumonia, atelectasis, hemoptysis, hyperinflation, and malignancy. OUTCOME AND PROGNOSISSection 9 of 11
Surgical resection is curative for most benign lung tumors. The 5- and 10-year survival rates following surgical resection of typical carcinoid tumors of the lung are 95% and 90%, respectively. The 5- and 10-year survival rates for patients with atypical carcinoids are 40-70% and 18-50%, respectively. Complete bronchoscopic resection for endobronchial carcinoid tumors at 1 and 10 years provides disease-free states of 100% and 94%, respectively. FUTURE AND CONTROVERSIESSection 10 of 11
In the future, negative biopsy results and negative PET scan findings may avoid further invasive procedures. REFERENCESSection 11 of 11
Article Last Updated: Jul 18, 2007 |
