Lung mass overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Maria Fernanda Villarreal, M.D. [2]
Synonyms and keywords:Pulmonary mass
Overview
Lung mass (also known as "Pulmonary mass") is defined as any area of pulmonary opacification that measures more than 30 mm (3 cms) in the lung. Lung mass are abnormal growths found in the lung which can be either be benign or malignant. The most common cause of a pulmonary mass is lung cancer. Other causes of lung mass include granuloma, lipoma, tuberculosis, and aspergillosis. Lung mass may be classified according to the location, imaging features, size, and distribution. The incidence rate of lung mass is approximately 58 per 100 000 individuals in the United States.[1] The incidence of lung mass increases with age; the median age at diagnosis is between 35 to 75 years. Lung mass has a wide age distribution. However, the majority of these lesions are more often diagnosed in adults. Males are more commonly affected with lung mass than females with male to female ratio of 2:1. There is no racial predilection for lung mass.[2] The most common symptom of a lung mass is cough, which will gradually persist over time. Other symptoms may include dyspnea, hemoptysis, chronic coughing, wheezing, and chest pain. In some cases, lung mass may be asymptomatic. A vital feature in the evaluation of lung mass includes malignancy assessment. The evaluation approach of lung mass starts with initial morphological evaluation of the mass (size, margins, contours, and growth). Other characteristics, such as: location, clinical features, and distribution may be helpful for the therapeutical management, surveillance, and follow-up of lung mass. Lung mass can be divided into 2 categories: benign pulmonary mass and malignant pulmonary mass. Based upon these categories, complementary diagnostic studies and management, include: PET/CT scan, CT scan, non-surgical biopsy, and surgical resection.[3]
Classification
Lung mass may be classified into 2 types: malignant or benign lung masses. In addition, lung mass can be sub-classified according to location, imaging features, size, and distribution.
Causes
The most common cause of a pulmonary mass is lung cancer. Other causes, include: granuloma, lipoma, tuberculosis, and aspergillosis.[4]
Differential Diagnosis
Lung mass may be differentiated according to clinical features, laboratory findings, imaging features, histological features, and genetic studies, from other diseases that cause cough, chest pain, or wheezing. Common differential diagnosis include: lung cancer, tuberculosis, pulmonary abscess, granulomas, and metastases.[5]
Epidemiology and Demographics
The incidence rate of lung mass is approximately 58 per 100 000 individuals in the United States. The incidence of lung masses increases with age; the median age at diagnosis is between 35 to 75 years. Males are more commonly affected with lung masses than females. The male to female ratio is approximately 2 to 1. There is no racial predilection for lung mass.[2]
Screening
According to the U.S. Preventive Services Task Force (USPSTF) there is sufficient evidence to recommend routine screening for lung masses. Screening for suspected lung cancer by low-dose computed tomography is recommended every year among smokers who are between 55 to 80 years old and who have history of smoke 30 pack-years or more and either continue to smoke or have quit within the past 15 years (grade B recommendation).[1][6]
Diagnosis
Evaluation of Lung Mass
A hallmark feature in the evaluation of lung mass is the malignancy assessment. The evaluation approach of lung mass will mainly depend in the initial morphological evaluation of the mass (size, margins, contours, and growth). Other characteristics, such as: location, clinical features, and distribution may be helpful for the therapeutical management, surveillance, and follow-up of lung mass. Lung mass can be divided into 2 categories: benign pulmonary mass and malignant lung mass. Based upon these categories, complementary diagnostic studies and management, include: PET/CT scan, CT scan, non-surgical biopsy, and surgical resection.[2]
Imaging
Computed tomography is the method of choice for the evaluation of lung mass. The evaluation of lung mass will depend on several characteristics, such as: calcification pattern, margins, location, distribution, and attenuation. Further evaluation of lung mass, should include other diagnostic studies, such as: bronchoscopy, sputum cytology, or mediastinoscopy. Other imaging study useful for the malignancy evaluation of lung mass is PET scanning, which may be helpful for the detection of occult disease and malignancy assessment.[2][7]
Staging
According to the American Joint Committee on Cancer (AJCC) staging system, there are 4 stages of malignant lung mass, based on 3 factors: tumor size, lymph node invasion, and metastasis. Each stage is assigned a letter and a number that designate T for tumor size, N for node invasion, and M for metastasis.[8]
History and Symptoms
The most common symptom of a lung mass is cough, which will gradually persist over time. Other symptoms may include: dyspnea, hemoptysis, wheezing, and chest pain. A positive history of smoking, exposure to asbestos, tuberculosis infection, or a high risk occupation may be suggestive of a lung mass. Symptoms related with lung mass will vary depending on the size and location of the tumor. Common symptoms of lung mass may also include loss of appetite, fatigue, and cachexia.[9][10]
Physical Examination
Physical examination findings of lung mass will depend on the location of the tumor. Lung mass with central location may cause crackling sounds, focal wheezing, voice hoarseness, and tachypnea. Lung mass with peripheral location can present with pleurisy findings, such as reduced chest expansion. Common physical examination of patients with lung mass, include: crackling or bubbling noises, decreased/absent breath sounds, and whispered pectoriloquy.[11]
Laboratory Studies
Laboratory findings associated with lung mass, include: complete blood count, electrolytes, calcium, alkaline phosphatase, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, creatinine, albumin, serum immunoglobulin E, and lactate dehydrogenase.[3]
Biopsy
Biopsy for lung mass may be classified into 2 categories: non-surgical biopsy and surgical biopsy. Biopsy findings associated with lung mass will depend on tumor histology. Common types of lung tissue biopsy for pulmonary mass, include: conventional bronchoscopic-guided transbronchial biopsy, bronchoscopic-transbronchial needle aspiration, endobronchial ultrasound-guided sheath transbronchial biopsy, and endobronchial ultrasound-guided transbronchial needle aspiration. Common indications for biopsy in lung mass, include: suspected lung cancer, malignant features (lymph node involvement).[12][13]
References
- ↑ 1.0 1.1 National Lung Screening Trial. Wikipedia. https://en.wikipedia.org/wiki/National_Lung_Screening_Trial Accessed on February 4,2016
- ↑ 2.0 2.1 2.2 2.3 Littleton JT, Durizch ML, Moeller G, Herbert DE (1990). "Pulmonary masses: contrast enhancement". Radiology. 177 (3): 861–71. doi:10.1148/radiology.177.3.2244002. PMID 2244002.
- ↑ 3.0 3.1 Spira A, Ettinger DS (2004). "Multidisciplinary management of lung cancer". N. Engl. J. Med. 350 (4): 379–92. doi:10.1056/NEJMra035536. PMID 14736930.
- ↑ Gadkowski LB, Stout JE (2008). "Cavitary pulmonary disease". Clin. Microbiol. Rev. 21 (2): 305–33, table of contents. doi:10.1128/CMR.00060-07. PMC 2292573. PMID 18400799.
- ↑ Bhatia K, Ellis S (2006). "Unusual lung tumours: an illustrated review of CT features suggestive of this diagnosis". Cancer Imaging. 6: 72–82. doi:10.1102/1470-7330.2006.0013. PMC 1693761. PMID 16829468.
- ↑ Davis AM, Cifu AS. Lung Cancer Screening. JAMA. 2014;312(12):1248-1249. doi:10.1001/jama.2014.12272.
- ↑ Albert RH, Russell JJ (2009). "Evaluation of the solitary pulmonary nodule". Am Fam Physician. 80 (8): 827–31. PMID 19835344.
- ↑ Stages of non–small cell lung cancer. Canadian Cancer Society. http://www.cancer.ca/en/cancer-information/cancer-type/lung/staging/?region=ab
- ↑ Non small cell lung cancer. Wikipedia. https://en.wikipedia.org/wiki/Non-small-cell_lung_carcinoma Accessed on February 24, 2016
- ↑ Raz DJ, Zell JA, Ou SH, Gandara DR, Anton-Culver H, Jablons DM (2007). "Natural history of stage I non-small cell lung cancer: implications for early detection". Chest. 132 (1): 193–9. doi:10.1378/chest.06-3096. PMID 17505036.
- ↑ Hyde L, Hyde CI (1974). "Clinical manifestations of lung cancer". Chest. 65 (3): 299–306. PMID 4813837.
- ↑ Herman M, Galanter M, Lifshutz H (1991). "Combined substance abuse and psychiatric disorders in homeless and domiciled patients". Am J Drug Alcohol Abuse. 17 (4): 415–22. PMID 1746503.
- ↑ Podbielski FJ, Rodriguez HE, Brown AM, Blecha MJ, Salazar MR, Connolly MM (2004). "Percutaneous biopsy in evaluation of lung nodules". JSLS. 8 (3): 213–6. PMC 3016799. PMID 15347106.