Flashcards in 5.10 - Intro to Pathology Pt 1: Neoplasia Deck (32)
Means new growth and is used to denote uncontrolled growth of cells whose proliferation cannot be adequately controlled by normal regulatory mechanisms operating in normal tissues.
The terms neoplasia and tumor are used synonymously, but realize that not all form tumors ( i.e. Leukemias), and not all swellings are neoplasms (inflammations).
The greek word for swelling "Onkos" which has been used to construct the term Oncology, the scientific word for the study of cancer.
Who determines the definitive diagnosis?
The definitive diagnosis of tumors, whether benign or malignant is achieved by the pathologic examination.
General Characteristics of Benign tumors
Have a limited growth potential and good outcome
Benign tumors Macroscopical
Are sharply demarcated from normal tissue and are often encapsulated. The capsule is usually composed of connective tissue. Benign tumors have an expansile growth and usually compress the normal surrounding tissue.
Benign tumors Microscopical
-Benign tumors are composed of cells that resemble the tissue from which they have arisen.
-The cells are composed of uniform population in which all the cells have the same features, with the regularly shaped round or oval nuclei but all the same size with evenly distributed chromatin with normal nucleoli.
-They also have a well developed cytoplasm.
Malignant tumors general characteristics
Grow uncontrollably and may eventually kill the host
Macroscopically malignant tumors
-They invade the surrounding tissue by infiltration, causing a hallmark "hemorrhage and Necrosis" within the tissue.
-Malignant tumors lack a capsule and are not sharply demarcated from normal tissue.
-Because of their infiltrative growth and lack of sharp borders, malignant tumors cannot be removed as easily as benign ones.
Microscopically Malignant tumors
-Malignant cells show prominent Anaplasia (disorganized growth) in that they exhibit new features not inherent to the tissues of their origins.
- Undifferentiated (very immature cells)
-Heterogeneous population of cells that often show mocked pleomorphism or variability (different sizes and shapes)
-The have uneven hyper chromatic nuclei that vary in shape and size. The nuclei are normally larger, mor prominent and may have multiple nucleoli. They are rapidly proliferating and have no specialized cytoplasmic function and therefore exhibit very little cytoplasm.
What is a high nuclear/cytoplasmic ration? (High N/C Ratio)
Because malignant tumors exhibit a large nucleus surrounded by a thin rim of cytoplasm, the ratio is 1:1 instead of the normal 1:5 ratio.
Variability in the size and shape of cells and or their nuclei
A cancer in which the cells are very immature and primitive and do not look like cells in the tissue from which it arose. As a rule an undifferentiated cancer is more malignant that a cancer of that type which is well differentiated. Undifferentiated cells are said to be anapestic.
A process by which cells move from one site to another in the body. It involves a spread of malignant tumor cells from a primary location to some other sire in the body. Only malignant tumor cells have this capacity. Benign tumors are always localized.
Are all malignant cells capable of metastasis?
No, some such as primary brain tumors cannot leave the area they started.
What are the three main pathways malignant cells spread in the body?
2) The bloodstream
3) Direct extension of the primary tumor, usually by seeding of the surface of body cavities (Renal cell carcinoma seeding to the adrenal gland)
Explain Benign Taxonomy
The cells of benign tumors usually retain the microscopic features of their tissue of origin. The tumors are thus named according to the cell type which they resemble the most, with the addition of the suffix "oma". Thus if epithelial and of glandular origin, the tumor is an Adenoma( colon tubular adenoma), if squamous the benign tumor is a papilloma (skin or laryngeal papillomas)
Benign Connective tissue tumors
If the benign tumor is of connective tissue origin, the same rules apply with "oma" being attached to the tissue of origin:
1) Cartiage tissue is a Chondroma
2) Osseous tissue is a Osteoma
3) Smooth muscle is a Leiomyoma
4) Fat tissue is a Lipoma
Explain Malignant tumor Taxonomy
-The malignant tumors of epithelial origin are called carcinomas
-(Squamous cell carcinoma, adenocarcinoma, traditional cell carcinoma, or mesothelioma, due to long term asbestos exposure)
-Tumors composed of unique cell types are named accordingly such as renal cell carcinomas, adrenocortical carcinomas, or hepatocellular carcinomas.
Explain Malignant connective tissue tumors
The name for the malignant tumors of connective tissue origin are coined from the root of the cell type and suffix "Sarcoma"
1) Fibrous tissue Fibrosarcoma
2) Fat tissue Liposarcoma
3) Bone tissue Osteosarcoma
4) Skeletal muscle is Phabdinyosarcoma
What suffix is applied to Benign tumors mostly
What suffix is applied to Malignant connective tissue tumors?
Define Tumor Grading
-Histologic grading is based on the degree of anaplasia and on the number of proliferating cells.
-Anaplasia is determined by the shape and irregularity of the cells large number of atypical mitoses, nuclear pleomorphism and tumor giant cells.
-Grading of cancer is done by the pathologist.
Define Tumor Staging
Describes the severity of an individual's cancer based on the magnitude of the original (primary) tumor as well as on the extent cancer has spread in the body.
What is a Grade 1 tumors?
What is a Grade 2 Tumor?
Moderately Differentiated tumor
What is a Grade 3 tumor?
Poorly or Undifferentiated Tumor
What factors contribute to the clinical staging of a tumor by the Oncologist?
1) The choice of medical versus surgical treatment approach to cancer us influenced by the stage of a tumor, which refers to the extent of spread.
2) The staging is done by clinically assessing the extent of tumor spread based on physical examination, radiographic studies, and biopsy results and takes into account the size and grading of the primary tumor and the presence or absence of lymph node and distant metastasis.
3) The TNM cancer staging system gives a number designation to tumor size, lymph node status and Metastasis to determine the stage.
Are there exceptions to the naming rules?
Yes not all tumors that end in "oma" are benign, the most important examples of this inconsistent nomenclature includes: Lymphomas, Melanomas, Astrocytomas, and Seminomas which are all malignant. Also, Malignant pediatric tumors composed of embryonic tissue are called "Blastomas"
Interpret the finding of the TNM staging System for tumors and relate it to the prognosis.
There are marked orations of this system depending upon which primary organ involved, and commonly used criteria in most includes tumor size, extent of local spread within the organ, lymph node metastasis and distant metastasis. Clearly the presence of lymph node metastasis mandates more aggressive treatment than does their absence, whereas the presence of distant metastasis is generally a contraindication to surgical intervention other than palliation.
What are Teratomas?
-Tumors derived from all three germ cell layers, usually in the testes or ovaries.
-Are named Teratomas (benign) or Teratocarcinomas (malignant). They may also be seen in the midline of the body (mediastinum or sacrococcygeal region.