A 56-year-old construction worker comes to the office after receiving a letter from his employer advising him of significant exposure to asbestos during a building project 25 years ago. He is currently asymptomatic and feels well. Medical conditions include hypertension and osteoarthritis, for which he takes amlodipine daily and ibuprofen as needed. The patient quit smoking 10 years ago and does not use alcohol or illicit drugs. Physical examination is within normal limits. Chest imaging is normal. He is concerned about his risk of developing cancer. Due to his occupational exposure, this patient is at greatest risk of malignancy arising from which of the following?

Question

A 56-year-old construction worker comes to the office after receiving a letter from his employer advising him of significant exposure to asbestos during a building project 25 years ago.  He is currently asymptomatic and feels well.  Medical conditions include hypertension and osteoarthritis, for which he takes amlodipine daily and ibuprofen as needed.  The patient quit smoking 10 years ago and does not use alcohol or illicit drugs.  Physical examination is within normal limits.  Chest imaging is normal.  He is concerned about his risk of developing cancer.  Due to his occupational exposure, this patient is at greatest risk of malignancy arising from which of the following?

Quizplus · Accepted Answer

11ec160b_3a05_746b_9249_ab3424391429_MD0001_00 Asbestos is a fiber composed of hydrated magnesium silicates commonly used in the shipbuilding, construction, and textile industries. Inhalation of fine asbestos fibers causes epithelial cell injury, activation of macrophages, and chronic interstitial inflammation and fibrosis. The major clinical manifestations of asbestos exposure include the following: Pleural disease includes pleural effusions and pleural plaques. Pleural plaques are a hallmark of asbestos exposure that typically affect the parietal pleura along the lower lungs and diaphragm. The plaques are composed of discrete circumscribed areas of dense collagen that frequently become calcified. Asbestosis is characterized by progressive pulmonary fibrosis that is most predominant in the lower lobes and by the presence of asbestos bodies (golden-brown beaded rods with translucent centers). Bronchogenic carcinoma is the most common malignancy associated with asbestos exposure. Smoking and asbestos exposure have a synergistic effect on the development of lung carcinoma, increasing the risk from 6-fold in nonsmoking patients with asbestos exposure to 60-fold in asbestos-exposed patients who smoke regularly. Malignant mesothelioma is a rare malignancy of the pleura for which asbestos is the only known environmental risk factor. It is less common than bronchogenic carcinoma in asbestos-exposed patients (Choice F). However, mesothelioma is more specific for heavy asbestos exposure. (Choice B) Direct-acting alkylating agents and benzene exposure are associated with acute leukemias, which occur due to malignant proliferation of hematopoietic stem cells. (Choice C) Aflatoxin exposure, which can occur after exposure to contaminated crops (eg, peanuts, corn), is a chemical risk factor associated with hepatocellular cancer, although viral hepatitis, cirrhosis, and alcohol abuse are more common risk factors. (Choice D) Epstein-Barr viral infection and heavy alcohol use, particularly when combined with smoking, increase the risk of nasopharyngeal cancer. (Choice E) Pancreatic cancer is strongly associated with tobacco use and obesity. However, this patient's asbestos exposure places him at higher risk of developing bronchogenic carcinoma. (Choice G) Beta-naphthylamine is used in aniline dyes and the rubber industry; it is associated with increased incidence of bladder carcinoma. Educational objective: Patients with a long history of asbestos exposure are at risk for developing asbestosis, pleural disease, and malignancies such as bronchogenic carcinoma and mesothelioma. Bronchogenic carcinoma is the most common malignancy in this population, although mesothelioma is more specific for asbestos exposure.

A 56-Year-Old Construction Worker Comes to the Office After Receiving