Radiographic Pathology RSMI 363

By

Dr. Amr A. Abd-Elghany, Ph.D.

Assistant professor, Department of Radiological and Medical imaging Sciences, College of Applied Medical

Sciences, Salman Bin Abdul-Aziz University.

Chapter 1Introduction to pathology

• Learning objectives• On completion of chapter 1, the student should be able to:• Define common terminology associated with the study of

disease.• Differentiate between signs and symptoms.• Describe the different types of disease classifications.• Cite characteristics that distinguish benign from malignant

neoplasm.• Describe the system used to stage malignant tumors.• Identify the difference in origin of carcinoma and sarcoma.

Common pathological terms

• Pathology is the study of disease.

• Disease is any abnormal disturbance of the function or structure of the human body as a result of some type of injury.

• Pathogenesis refers to the sequence of events producing cellular changes that lead to observable changes known as manifestations.

• Manifestations can be displayed in a variety of fashions.

• A symptom refers to the patient perceptionإدراك of the disease (e.g. headache).

• Symptoms are subjective, and only the patient can identify these manifestations.

• A sign is an objective manifestation that can be detected by the physician during examination (e.g. Fever, swelling, and skin rash).

• A group of signs and symptoms that characterizes a specific abnormal disturbance is a syndrome.

• Some disease processes, especially in the early stages do not produce symptoms and are termed asymptomatic (e.g. aortic valve stenosis, atrial fibrillation).

• Etiology: is the study of the cause of a disease.• Nosocomial infections: also known as a hospital-acquired

infection or HAI, is an infection whose development is favored by a hospital environment. Such infections include fungal and bacterial infections and are aggravated by the reduced resistance of individual patients (e.g. staphylococcal infection that follows hip replacement surgery).

• Iatrogenic reactions: are adverse responses to medical treatment itself (e.g. a collapsed lung that occurs in response to a complication that arises during arterial line placement). If no causative factor can be identified a disease is termed Idiopathic السبب .مجهول

• Acute disease have a quick onset and last a short period of time (e.g. pneumonia).

• Chronic diseases may manifest more slowly and last a very long time.• Prognosis a medical term used to predict the course مسار and end of

a disease and the outlook توقعات based on that prediction (e.g. 45% of patients with severe septic shock will die within 28 days).

• Pathologic conditions can alter the normal body tissue in a variety of ways.

• Sometimes the disease is destructive, decreasing the normal tissue density such as atrophy need low dose radiation for good diagnosis and vise versa.

• Epidemiology األوبئة is the investigation of disease in علمlarge groups (statistics community).

• Prevalence اإلنتشار number of cases in a given معاملpopulation.

• Incidence number of new cases in a given period of time.

• Mortality rate: the number of deaths caused by a particular disease averaged over population.

• Morbidity rate: the ratio of sick : well people in a community.

The human genome project

• The human Genome project was a 13 years (1990-2003) in USA.

• The goals of the project :

1. Identify all the approximately 20.000 to 25.000 genes in human DNA.

2. determine the sequences of the three billion chemical base pairs that make up human DNA.

3. Store this information in databases.

4. Improve tools for data analysis.

5. Transfer related technologies to the private sector.

Disease classifications

Congenital And

Hereditary Inflammatory Degenerative Metabolic Traumatic Neoplastic

Congenital Diseases•Diseases present at birth and resulting from genetic or environmental factors (e.g. Down syndrome an affected individual has 47 chromosomes rather than 46 autosomal extra chromosome).

•About 2% to 3% of newborn have congenital disease.

•Caused by abnormalities in the number and distribution of chromosomes.

•Congenital defect is not necessarily hereditary because it may have been acquired in utero from maternal infections, radiation or drugs.

Hereditary diseases

• Are caused by developmental disorders genetically transmitted from either parent to a child.

• Sex linked: a genetic abnormality present on the sex chromosome (e.g. hemophilia).

• Autosomal inheritance: an abnormality on one of the other 22 chromosomes. It could be dominantسائد or recessiveمتنحي (transmitted by both parents genes).

A congenital defect not necessarily hereditary because it may have been acquired in utero.Intrauterine injury during a critical point of development can occur from maternalInfections, radiation, or drugs.

• Caused by the body reactions to a localized injurious agent (e.g. pneumonia).

• Type of inflammatory disease include infective, toxic, and allergic diseases.

• Infective disease results from invasion by microorganisms such as viruses, bacteria, or fungi.

• Toxic results from poisoning by biological substance.

• Allergic results from overreaction of the body own defense.

• Autoimmune disorder antibodies attack the patient tissue not the foreign antigens (e.g. Rheumatoid arthritis).

Inflammatory Diseases

Cell death

Product of cell necrosis Systemic response

Fever leukocytosis

Attraction of leukocytes

Migration of white cells to site of

necrosis

Increased capillary

permeability

Extravasation of

fluid

Capillary Dilatation

Increased blood flow

Slowing of flow

Heat Redness Tenderness Swelling Pain

Cell death

Chemical injury

Physical injury Microbial injury

Fig. Local and systemic effects of cell necrosis induced by various agents

• Caused by deteriorationتدهور of the body and unusually are age-related diseases such as atherosclerosis, osteoarthritis.

Degenerative Diseases

Metabolic Diseases

• Caused by disturbance of normal physiologic metabolic function such as lack of hormones secretions (endocrine disorders) such as diabetes and hyperparathyroidism.

Traumatic Diseases

• Caused by mechanical injury such as crushing, twisting of body part or from the effects of ionizing radiation on the human body. In addition from extreme hot or cold temperature burns and frostbiteالتجمد

• Results in new abnormal tissue growth.

• Lesion is a term used to describe the many types of cellular change that can occur in response to disease.

• A benign neoplasm remains localized and is generally noninvasive.

• Malignant neoplasm continues to grow, spread, and invade other tissues.

• Cells are classified as either:

• Differentiated or Undifferentiated

Depending on the resemblance of the new cells to the original cells in the host organ.

Neoplastic Diseases

• If the differences are small, the growth is termed differentiated and has a low probability for malignancy.

• If the cell within the neoplasm exhibit differences, the growth is termed undifferentiated and have a higher probability of malignancy.

• Metastasis the spread of malignant cancer cells.

• Metastatic spread can occur in a variety of ways:

1. Hematogenous spread the cancerous cells invade the circulatory system, they made be spread via blood vessels.

2. Lymphatic spread the cancer cells spread via the lymphatic system.

• Invasion the cancer cells spread into surrounding tissue by virtue ofبمقتضى the close proximity المكاني .القرب

• Seeding the cancer cells travel to a distant organ.

• Carcinoma is one type of cancer and is derived from epithelial tissue.

• Sarcoma arises from connective tissue.

• Leukemia arises from blood cells.

• Lymphoma arises from lymphatic cells.

The staging of cancer

• TNM system

Size of untreatedPrimary tumor

As the size increase lymph nodule occurs

Leading metastases

The addition of numbers to these letters indicate the extent of malignancy.To indicates no tumor, T1, T2, T3, and T4 indicates increasing size.No idicates lack of nodules, N1, N2, N3 indicate increasing involvement of regional lymph nodes.Mo idicates no distant metastasis and M1 indicates the presence of distant metastasis.

Altered cellular biology

• Cells adapt to avoid injury.

• When a cell is injured it can response in several ways, and many cells adapt by altering their pattern of growth.

Atrophy

Decrease in cell size.

MRI scan

Hypertrophy: Increase in cell size

-Blood travels through the right ventricle to the lungs via the pulmonary arteries. -If conditions occur which decrease pulmonary circulation, meaning blood does not flow well from the heart to the lungs, extra stress can be placed on the right ventricle. -This can lead to right ventricular hypertrophy.

Hyperplasiaincrease in cell number in the tissueAs a result excessive proliferation.

Metaplasia A conversion of one cell type intoanother cell type that is not normal for that tissue.

Dysplasia

Refers to abnormal changes of mature cells.