Carcinoma Of The Lungs

carcinoma of the lungs

• Primary lung tumor— the tumor arises from the lung tissue – 90%~95% originates from the bronchial epithelium –bronchogenic carcinomas – 5% has other origin, such as alveolar epithelial, etc.

• Incidence: – The number one cause of cancer-related deaths – about 1/3 of cancer deaths in men – the leading cause of cancer deaths in women – The peak incidence of lung cancer occurs between ages 45 and 75 years.

• Etiology and Pathogenesis: – Cigarette smoking • Compared with nonsmokers, average smokers have 10-fold, heavy smokers have at least 20fold greater risk of developing lung cancer • Eighty percent of lung cancers occur in smokers • Cessation of smoking for 10 years reduces risk to control level

• Etiology – Occupational hazards • The occupation exposed to asbestos, nickel, chromates, coal, etc.

– Air pollution

Morphology • Macroscopic Classification – Central pattern • the cancers tend to arise centrally in major bronchi. Mainly located in hilus.

– Peripheral pattern • the cancers are usually peripherally located.

– Diffuse pattern • the cancers are multiple diffuse nodules that may fuse to produce pneumonia-like consolidation.

Central pattern

Peripheral pattern

Diffuse pattern

•

Histologic Classification – Non-Small Cell Carcinoma (NSCLC) • •

Squamous cell carcinoma Adenocarcinoma

– Small Cell Lung Carcinoma (SCLC) – Combined Patterns

• Several common features: – The majority arise in the lining epithelium of major bronchi, usually close to the hilus of the lung. – All patterns are associated with cigarette smoking; the strongest association is with squamous cell and small cell carcinoma. – All patterns are aggressive

Squamous cell carcinoma • Incidence: – the most common histologic pattern • 30-50% of all lung cancers • 80-85% of the central pattern

– more common in men than in women

Squamous cell carcinoma • lMorphology: – Macroscopically : • well-defined tumor mass central in major bronchi

Squamous cell carcinoma – Histologically • squamous cell carcinoma – Well-differentiated squamous cell carcinomas show keratin pearls and intercellular bridges. – Poorly-differentiated squamous cell carcinomas have only minimal residual squamous cell features.

Intercellular bridges

• Metastasis: – squamous cell carcinoma are prone to metastasize by lymph – local hilar lymph nodes are usually affected

Adenocarcinoma • Most common type in women and nonsmokers • Peripheral located, discrete nodule. • Histologically, showing obvious glandular elements or solid masses with only occasional mucin-producing glands and cell.

Bronchioloalveolar carcinoma is a variant of adenocarcinoma. In this picture it resembles pneumonia.

•Special type: • bronchioloalveolar cell carcinoma

Bronchioloalveolar carcinoma The arrows point to linear arrangements of neoplastic cells.

Tumor cells line alveolar walls. Note that the tumor cells here are larger and more hyperchromatic than the normal bronchiolar epithelium of the airway at

Small cell lung carcinomas(SCLC) • Incidence: – relatively common (20-25%), and also more common in men than in women.

• Morphology: – Macroscopically • pale, gray, centrally located masses with extension into the lung parenchyma and early involvement of the hilar and mediastinal lymph nodes.

Small cell lung carcinomas(SCLC) • Histologically: – “oat cell” • small 、 dark 、 round-to-oval 、 spindle-shaped or lymphocyte-like cancer cells • with scant cytoplasm • with hyperchromatic nuclei • mitoses are numerous

SCLC

• Metastasis: – They tend to early metastasize by blood stream – SCLCs have invariably spread by the time they are first detected, even if the primary tumor appears small and localized. – They are very sensitive to chemotherapy but invariably recur.

Traits of SCLC • SCLCs are rapidly growing lesions that tend to infiltrate widely and metastasize early in their course and so are rarely resectable.

• They are derived from neuroendocrine cells of the lung, which are characterized by secreting a host of polypeptide hormones including ACTH, calcitonin, gastrin-releasing peptide, and so on. Hence, these tumors are associated with a variety of paraneoplastic syndromes.

Clinical course • often silent and insidious lesions that have spread so as to be unresectable before they produce obvious symptoms. • Chronic cough and expectoration may be the common symptoms in the early stage.