Transcript 6. lung tumors

Tumors of the Lung
By
Dr. Abdelaty Shawky
Assistant professor of pathology
* Classification:
1. Benign tumors:
- Papilloma.
- Fibroma.
- Chondroma.
2. Locally malignant tumors:
- Bronchial carcinoid
3. Malignant tumors:
A. Primary M. tumors:
- Bronchogenic carcinoma.
- Lymphoma.
- Sarcomas.
B. Secondaries.
• Lung cancer is currently the most frequently
diagnosed major cancer in the world and the
most common cause of cancer mortality
worldwide.
• This is largely due to the carcinogenic effects
of cigarette smoke. Over the coming decades,
changes in smoking habits will greatly
influence lung cancer incidence and mortality.
• Cancer of the lung occurs most often between
ages 40 and 70 years, with a peak incidence in
the fifties or sixties. Only 2% of all cases
appear before the age of 40.
* Etiology and Pathogenesis:
1. Tobacco Smoking.
• 87% of lung carcinomas occur in active smokers or
those who stopped recently.
• There is an association between the frequency of lung
cancer and
(1) the amount of daily smoking.
(2) the tendency to inhale.
(3) the duration of the smoking habit.
• Cigar and pipe smoking also increase risk,
although much more modestly than smoking
cigarettes.
2. Industrial Hazards:
• Certain industrial exposures increase the risk of
developing lung cancer.
• High-dose ionizing radiation is carcinogenic. There was
an increased incidence of lung cancer among survivors
of the Hiroshima and Nagasaki atomic bomb blasts.
• Exposure to asbestos.
* Classification of lung cancer:
1. Squamous cell carcinoma (25% to 40%)
2. Adenocarcinoma (25% to 40%)
3. Small cell carcinoma (20% to 25%)
4. Large cell carcinoma (10% to 15%)
* Morphology:
• Lung carcinomas arise most often in the hilum of the
lung. These are usually squamous cell carcinoma.
• A small number of primary carcinomas of the lung arise
in the periphery of the lung. These are usually
adenocarcinomas.
• Squamous cell carcinoma of the lung begins as
an area of in situ cytologic dysplasia that, over
an unknown interval of time, yields a small
area of thickening of bronchial mucosa.
• With progression, this small focus, usually less
than 1 cm, then assumes the appearance of
an irregular mass erodes the lining epithelium.
• The tumor may then follow a variety of forms. It may
continue to fungate into the bronchial lumen to
produce an intraluminal mass (fungating tumor). It
can also rapidly penetrate the wall of the bronchus
to infiltrate along the peri-bronchial tissue into the
adjacent region of the carina or mediastinum
(infiltrating tumor).
• In almost all patterns, the neoplastic tissue is graywhite and firm to hard. Especially when the tumors
are bulky, focal areas of hemorrhage or necrosis may
appear to produce yellow-white mottling and
softening.
Lung carcinoma. The gray-white tumor tissue is seen infiltrating
the lung substance. Histologically, this large tumor mass was
identified as a squamous cell carcinoma.
Cancer lung
* Spread of cancer lung:
1. Direct spread: to pleura, pericardium….
2. Lymphatic spread: The frequency of nodal
involvement varies slightly with the histologic pattern but
averages greater than 50%.
3. Hematogenous spread: to any organ. The liver (30% to
50%), brain (20%), and bone (20%) are additional favored
sites of metastases.
Squamous Cell Carcinoma
• Squamous cell carcinoma is most commonly found in
men and is closely correlated with a smoking history.
• Histologically, this tumor is characterized by the
presence of keratinization and/or intercellular bridges.
• Keratinization may take the form of squamous pearls
or individual cells with markedly eosinophilic dense
cytoplasm . These features are prominent in the welldifferentiated tumors, are easily seen but not
extensive in moderately differentiated tumors, and are
focally seen in poorly differentiated tumors.
Squamous cell carcinoma
Adenocarcinoma
• This is a malignant epithelial tumor with glandular
differentiation.
• Adenocarcinoma is the most common type of lung
cancer in women and nonsmokers.
• As compared to squamous cell cancers, the lesions
are usually more peripherally located, and tend to be
smaller.
• Adenocarcinomas grow more slowly than squamous
cell carcinomas but tend to metastasize widely and
earlier.
Small Cell Carcinoma
• This highly malignant tumor has a distinctive cell type.
The epithelial cells are small, round, oval, and spindleshaped.
• The cells grow in clusters that exhibit neither glandular
nor squamous organization. Necrosis is common and
often extensive.
• Grading is inappropriate, since all small cell carcinomas
are high grade.
• Small cell carcinomas have a strong relationship to
cigarette smoking; only about 1% occur in
nonsmokers.
• They occur both in major bronchi and in the periphery
of the lung.
• They are the most aggressive of lung tumors,
metastasize widely, and are virtually incurable by
surgical means.
Small cell carcinoma
Large Cell Carcinoma
• This is an undifferentiated malignant epithelial tumor
that lacks the cytologic features of small cell
carcinoma and glandular or squamous
differentiation.
• The cells typically have large nuclei.
Staging of cancer lung
T: Tumor size and extension.
•
•
•
•
T1: Tumor <3 cm
T2: Tumor >3 cm
T3: Tumor with involvement of chest wall
T4: Tumor with invasion of mediastinum, heart, great vessels, trachea, esophagus,
vertebral body, or carina or with a malignant pleural effusion.
N: (lymph nodes)
•
•
•
•
N0: No demonstrable metastasis to regional lymph nodes
N1: Ipsilateral hilar nodal involvement
N2: Metastasis to ipsilateral mediastinal lymph nodes
N3: Metastasis to contralateral mediastinal or hilar lymph nodes,
M: (metastasis)
•
•
M0: No (known) distant metastasis
M1: Distant metastasis present
* Prognosis of cancer lung:
• The outlook is poor for most patients with
lung carcinoma.
• In general, the adenocarcinoma and squamous cell
patterns tend to remain localized longer and have a
slightly better prognosis than do the undifferentiated
cancers, which usually are advanced lesions by the time
they are discovered.
• Surgical resection for small cell carcinoma is so
ineffective that is this cancer is particularly sensitive to
radiotherapy and chemotherapy.
LUNG METASTASES (SECONDARIES)
More common than the 1ry tumors.
*Two forms
I. Metastases reach through pulmonary artery:
From malignant melanoma, hepatoma, encocrine carcinomas,
urogenital carcinoma (renal cell carcinoma and testicular
tumors), sarcomas and leukaemias.
N/E: multiple nodules, variable in size scattered all over the lung
lobes especially at the periphery. Metastases from RCC and
seminoma are large in size and spherical in shape called
“cannon-ball secondaries”.
M/P: like its 1ry.
II. Metastases reach through lymphatics:
From cancer breast, abdominal carcinomas and lymphoma.
Metastatic adenocarcinoma in the lung