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File:IPLab7Bronchogenic9.jpg|This high-power photomicrograph of tumor shows the cytologic detail of a less-differentiated area of neoplasm with cellular anaplasia.
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== Study Questions ==
* <spoiler text="What are the four main histologic classifications of bronchiogenic carcinoma and what are their relative frequencies?">Squamous cell carcinoma, and adenocarcinoma occur at approximately equal frequency, 25 to 40% each; small cell carcinoma, 20 to 25%; and large cell carcinoma, 10 to 15%.</spoiler>
* <spoiler text="What is the probable etiology of bronchiogenic carcinoma?"># There is a positive relationship between tobacco smoking and lung cancer. Compared with nonsmokers, cigarette smokers have a ten-fold greater risk of developing lung cancer, and heavy smokers (more than 40 cigarettes per day for several years) have at least a 20-fold greater risk. Eighty per cent of lung cancers occur in smokers.
# Industrial hazards (uranium, asbestos, etc.).
# Air pollution (radon).
# Genetic factors. Occasional familial clustering has been observed suggesting a genetic component to lung cancer. Dominant oncogenes (c-myc in small cell carcinoma & K-ras in adenocarcinomas) and loss or inactivation of recessive tumor suppressor genes (p53 & retinoblastoma) have been reported in lung cancer.
# Scarring. Some lung cancers arise in the area of old scars and are termed scar carcinomas.</spoiler>
* <spoiler text="What are some of the paraneoplastic syndromes associated with bronchiogenic carcinoma?"># Antidiuretic hormone (ADH), inducing hyponatremia due to inappropriate ADH secretion;
# adrenocorticotropic hormone (ACTH), producing Cushing’s syndrome;
# parathormone, parathyroid hormone-related peptide, prostaglandin E, and some cytokines, all implicated in the hypercalcemia often seen with lung cancer;
# calcitonin, causing hypocalcemia;
# gonadotropins, causing gynecomastia; and
# serotonin, associated with the carcinoid syndrome. The incidence of clinically significant syndromes related to these factors ranges from 1 to 10% of all lung cancer patients. Any one of the histologic types of tumors may occasionally produce any one of the hormones, but tumors producing ACTH and ADH are predominantly small cell carcinomas and those producing hypercalcemia are mostly squamous cell tumors.</spoiler>
* <spoiler text="What is the prognosis for patients with bronchiogenic carcinoma?">The clinical course is somewhat variable but in general the prognosis is poor with a 5 year survival of approximately 9%.</spoiler>
{{IPLab 7}}
[[Category: IPLab:Lab 7]]