4Neoplasia Flashcards
Define Neoplasia
Means “New Growth”.
Used to denote uncontrolled growth of cells whose proliferation cannot be adequately controlled by normal regulatory mechanisms operating in normal tissues.
What does proliferation of neoplastic cells lead to?
Masses called TUMORS, a latin word which means swelling
Are neoplasms and tumors the same?
The terms neoplasia and tumor are used synonymously, but not all neoplasms form tumors (I.e. Leukemias), and not all swellings are neoplasms (I.e. Inflammations)
How do we classify tumors?
clinically, which takes into account the presentation of the patient, and the outcome of the disease, as well as histologically, which gives the morphologic make-up the the neoplasm.
Benign vs malignant tumors
Benign: Have limited growth and potentially a good outcome
Malignant: grow uncontrollably and may eventually kill the host
How are tumors diagnosed?
The definitive diagnosis of tumors, whether benign or malignant is achieved by the pathologic examination.
Macroscopic Features of Benign Tumors
- Grossly, benign tumors 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.
Macroscopic Features of Malignant Tumors
- Malignant tumors lack a capsule and are not sharply demarcated from normal tissue.
- They invade the surrounding tissue by infiltration, causing a hallmark “HEMORRAGE AND NECROSIS”within the tissue.
- Because of their INFILTRATIVE growth and lack of sharp borders, malignant tumors cannot be removed as easy as benign ones
Metastasis
- Denotes a process in which cells move from one site to another in the body.
- It involves a spread of tumor cells from a primary location to some other site in the body.
Do both malignant and benign tumors metastasize?
- Only malignant tumor cells have this capacity
- Benign tumors always remain localized
- Not all malignant cells are capable of causing metastasis (i.e. primary brain tumors).
spread of malignant cells occurs through three main pathways
- The lymphatics (i.e. Breast cancer)
- The bloodstream (i.e. Many cancers)
- Direct extension of the primary tumor, usually by seeding of the surface of body cavities (i.e.Renal cell carcinoma seeding to the adrenal gland)
Taxonomy of Benign Tumors
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”.
How do you name benign tumors based on origin, give examples
-If epithelial and of glandular origin, the tumor is an Adenoma (i.e. thyroid follicular adenoma, or hepatic adenoma), if squamous, the benign tumor is a Papilloma (i.e. skin or laryngeal papillomas).
-If the benign tumor is of mesenchymal or connective tissue origin, the same rules apply with “oma” being attached to the tissue of origin.
Cartilage tissue is a Chondroma
Osseous tissue is a Osteoma
Smooth muscle is a Leiomyoma
Fat tissue is a Lipoma
Blood vessel is a Angioma
Skeletal muscle is a Rhabdomyoma
Fibrous Tissue (collagen) is a Fibroma
Taxonomy of Malignant Tumors
The malignant tumors of epithelial origin are called “Carcinomas”……Squamous cell carcinoma (oral cavity or skin), Adenocarcinoma (i.e. prostate, breast, ovary, stomach or colon) or Transitional cell carcinoma (i.e. pelvis of kidneys or bladder)
How are tumors composed of unique cell types named?
such as renal cell carcinomas, adrenocortical carcinomas, or hepatocellular carcinomas, which all are “Adenocarcinomas”.
