eMedicine Specialties > Thoracic Surgery > Tumors
Benign Lung Tumors
Updated: Jun 11, 2009
Introduction
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).
Problem
Although 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.
Frequency
Benign 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.
Etiology
The cause of benign lung tumors is not known.
Pathophysiology
The 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.
Hamartomas
Hamartomas (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 Adenomas
Bronchial 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 Adenomas
Mucous 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 Types
Tracheobronchial 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.
Presentation
When 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.1
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.1
Indications
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 Anatomy
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.
Contraindications
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.
Workup
Laboratory Studies
- Perform a complete preoperative evaluation on all patients who undergo tissue sampling.
- The cell count helps to determine the general health status of the patient and also to diagnose complications such as pneumonia and anemia.
- Determine adequacy of the platelet function and perform coagulation studies before the patient undergoes any invasive procedures.
- Electrolytes and renal and liver function tests help to evaluate the presence of an abnormality that indicates the need for either intervention or further workup before performing an invasive procedure.
- Tuberculin skin test
- Sputum cytologic and microbiological studies
- A patient with a carcinoid tumor, with or without carcinoid syndrome, may exhibit a high level of serotonin and 5-hydroxyindoleacetic acid (5-HIAA).
- Arterial blood gas and pulmonary function tests (PFTs) are indicated in patients presenting with shortness of breath and are indicated before invasive procedures or thoracotomy. The presence of hypoxia and hypercarbia generally suggests poor tolerability for resective surgery. PFTs are useful tests when determining patients' suitability for lung resection. Patients must have satisfactory parameters as measured by forced expiratory volume in one second (FEV1) and diffusion capacity of lung for carbon monoxide (DLCO).
- Recently, bronchoscopic resection offers an alternative to surgical resection of benign endobronchial tumors. At 1 and 10 years, respectively, 100% and 94% of completely resected carcinoids were free of disease.2
Imaging Studies
- Chest radiograph (posteroanterior [PA] and lateral views) is required. Review all previous chest radiographs when available. Reviewing helps to determine the onset and doubling time. Chest radiograph provides information about size, morphology, the presence of calcifications, and spicula. Benign lesions tend to have calcium deposited in central, peripheral, concentric, "popcorn," or homogeneous patterns, whereas eccentric patterns of calcifications are more characteristic of malignancies. These characteristics help when determining if the tumor is benign or malignant, although not with certainty. If a lesion has not changed over 2 years on radiographic evaluation, that lesion can generally be safely considered benign.
- Perform a chest computed tomography (CT) scan with and without contrast. Using both contrast and noncontrast examinations can help delineate calcification, can better confirm hamartomas and arteriovenous malformations, and can enhance the appearance of malignant tumors. Using iodinated contrast also provides more details about size, the presence of satellite lesions, the status of perihilar and mediastinal lymph nodes, and, when used in conjunction with noncontrast studies, it provides a more detailed definition of calcification.
- Use of MRI is limited; however, it is useful in defining tumor invasion of the great vessels.
- Positron emission tomography (PET) has been advanced as a method to distinguish benign lung tumors from malignant lung tumors. Unfortunately, some overlap exists with PET scanning, some lesions remain indeterminate even after PET scanning, and some lung cancers (bronchoalveolar) are not metabolically active on PET imaging.
Other Tests
- ECG is required before surgery as part of the preoperative cardiac risk factor assessment. Address the presence of major arrhythmia and ischemia before performing the planned procedure.
Diagnostic Procedures
- Fiberoptic bronchoscopy: Both rigid and fiberoptic bronchoscopy are useful for diagnosing endobronchial benign lung tumors. Biopsy or bronchial brushing can be performed with this procedure, as well as excision of pedunculated endobronchial lesion. Sensitivity for detection of malignancy is 10-30% when nodules are peripheral and small (<2 cm). However; recent advances in bronchoscopy, such as electromagnetic navigation and endobronchial ultrasound-guided transbronchial needle biopsy, may offer improved results in the evaluation of pulmonary nodules and mediastinal adenopathy.3 Bronchoscopic resection also offers an alternative to surgical resection for benign endobronchial tumors. At 1 and 10 years, respectively, 100% and 94% of completely resected carcinoids were free of disease.2
- Percutaneous biopsy/guided transthoracic needle aspiration biopsy: The tumor must be easily accessible. Percutaneous biopsy/guided transthoracic needle aspiration biopsy is performed under CT scan or fluoroscopy guidance and has a yield as high as 85% for diagnosis. A major complication is pneumothorax, with an incidence that may be as high as 20-25%.
- Video-assisted thoracoscopy:4,5,6 A biopsy can be obtained from a superficial pleural-based lesion, or the lesion can be resected using this approach.
- Open biopsy: This procedure may occasionally be required when the etiology of a pulmonary nodule is questioned after thorough workup. Thoracotomy is planned after the appropriate workup and plan of management is decided. The extent of resection is decided intraoperatively.
Histologic Findings
See Pathophysiology.
Treatment
Medical Therapy
A 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 Therapy
The 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 Details
Determine operability and resectability and take steps to prevent or limit operative and postoperative complications.
Intraoperative Details
Anesthesia 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 Details
Triage the patient to the surgical ICU or postoperative recovery floor.
Follow-up
When 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.
Complications
Possible complications due to benign lung tumors include pneumonia, atelectasis, hemoptysis, hyperinflation, and malignancy.
Outcome and Prognosis
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.7 Complete bronchoscopic resection for endobronchial carcinoid tumors at 1 and 10 years provides disease-free states of 100% and 94%, respectively.2
Future and Controversies
In the future, negative biopsy results and negative PET scan findings may avoid further invasive procedures.
References
Dholakia S, Rappaport DC. The solitary pulmonary nodule. Is it malignant or benign?. Postgrad Med. Feb 1996;99(2):246-50. [Medline].
Luckraz H, Amer K, Thomas L, Gibbs A, Butchart EG. Long-term outcome of bronchoscopically resected endobronchial typical carcinoid tumors. J Thorac Cardiovasc Surg. 2006;132(1):113-5. [Medline].
Gildea TR, Mazzone PJ, Karnak D, Meziane M, Mehta AC. Electromagnetic navigation diagnostic bronchoscopy: a prospective study. Am J Respir Crit Care Med. 2006;174(9):982-9. [Medline].
Kaiser LR, Shrager JB. Video-assisted thoracic surgery: the current state of the art. AJR Am J Roentgenol. 1995;165(5):1111-7. [Medline].
Landreneau RJ, Mack MJ, Hazelrigg SR, et al. Video-assisted thoracic surgery: basic technical concepts and intercostal approach strategies. Ann Thorac Surg. 1992;54(4):800-7. [Medline].
Landreneau RJ, Hazelrigg SR, Mack MJ, et al. Postoperative pain-related morbidity: video-assisted thoracic surgery versus thoracotomy. Ann Thorac Surg. 1993;56(6):1285-9. [Medline].
Travis WD, Rush W, Flieder DB, et al. Survival analysis of 200 pulmonary neuroendocrine tumors with clarification of criteria for atypical carcinoid and its separation from typical carcinoid. Am J Surg Pathol. 1998;22(8):934-44. [Medline].
Goroll AH, Mulley AG. Evaluation of the solitary pulmonary nodule. In: Primary Care Medicine. 3rd ed. Philadelphia, Pa: Lippincott-Raven Publishers; 1995:245-50.
Kulke MH, Mayer RJ. Carcinoid tumors. N Engl J Med. 1999;340(11):858-68. [Medline].
Liebow AA. Tumors of the lower respiratory tract. In: Atlas of tumor pathology. Washington, DC: Armed Forces Institute of Pathology; 1952.
Minna JD. Neoplasms of the lung. In: Fauci AS, Braunwald E, Isselbacher KJ, et al. Harrison's Principles of Internal Medicine. 14th ed. New York, NY: McGraw-Hill; 1998:552-62.
Takahashi N, Oizumi H, Yanagawa N. A bronchial glomus tumor surgically treated with segmental resection. Interactive cardiovascular and thoracic surgery. 2005;[Full Text].
Tomashefski JF Jr. Benign endobronchial mesenchymal tumors: their relationship to parenchymal pulmonary hamartomas. Am J Surg Pathol. Sep 1982;6(6):531-40. [Medline].
Keywords
lung tumor, lung tumors, benign lung tumor, benign lung neoplasms, lung cancer, lung lesion, 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, lung treatment
Contributor Information and Disclosures
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; Cardiovascular and Thoracic Surgeon, HeartCare Midwest, SC
Dale K Mueller, MD is a member of the following medical societies: American College of Chest Physicians, American College of Surgeons, American Medical Association, American Medical Writers Association, Chicago Medical Society, Illinois State Medical Society, and Society of Thoracic Surgeons
Disclosure: Nothing to disclose.
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
Norvin Perez, MD is a member of the following medical societies: American College of Emergency Physicians and American Medical Association
Disclosure: Nothing to disclose.
Oluyinka S Adediji, MD, Consulting Staff, Department of Adult and General Medicine, Health Services Incorporated, Montgomery, Alabama
Oluyinka S Adediji, MD is a member of the following medical societies: American College of Physicians and American Medical Association
Disclosure: Nothing to disclose.
Medical Editor
Richard Thurer, MD, B and Donald Carlin Professor of Thoracic Surgical Oncology, Miller School of Medicine, University of Miami
Richard Thurer, MD is a member of the following medical societies: American Association for Thoracic Surgery, American College of Chest Physicians, American College of Surgeons, American Medical Association, American Thoracic Society, Florida Medical Association, Society of Surgical Oncology, and Society of Thoracic Surgeons
Disclosure: Nothing to disclose.
Pharmacy Editor
Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.
Managing Editor
Daniel S Schwartz, MD, FACS, Assistant Clinical Professor of Cardiothoracic Surgery, Mount Sinai School of Medicine; Chief of Thoracic Surgery, Huntington Hospital
Daniel S Schwartz, MD, FACS is a member of the following medical societies: American College of Chest Physicians, American College of Surgeons, Society of Thoracic Surgeons, and Western Thoracic Surgical Association
Disclosure: Nothing to disclose.
CME Editor
Rajalaxmi McKenna, MD, FACP, Consulting Staff, Department of Medicine, Southwest Medical Consultants, SC, Good Samaritan Hospital, Advocate Health Systems
Rajalaxmi McKenna, MD, FACP is a member of the following medical societies: American Society of Clinical Oncology, American Society of Hematology, and International Society on Thrombosis and Haemostasis
Disclosure: Nothing to disclose.
Chief Editor
John Geibel, MD, DSc, MA, Vice Chairman, 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
John Geibel, MD, DSc, MA is a member of the following medical societies: American Gastroenterological Association, American Physiological Society, American Society of Nephrology, Association for Academic Surgery, International Society of Nephrology, New York Academy of Sciences, and Society for Surgery of the Alimentary Tract
Disclosure: AMGEN Royalty Other
© 1994-
by Medscape.
All Rights Reserved
(http://www.medscape.com/public/copyright)