Week 3: Neoplasia I Flashcards
What is non-neoplastic cell proliferation?
Controlled cell growth induced by a stimulating agent, abates following removal of stimulating agent
What is neoplastic cell proliferation?
Unregulated cell growth which occurs and persists in the absence of an inducing agent?
What is a tumor?
Swelling generically used to describe a neroplastic process. Tumors are not specifically benign or malignant.
What are the differences in tumor clonality?
Neoplastic cells are monoclonal in origin (come from a single cell
Non-neoplastic cell proliferation is generally polyclonal
What are the two forms of neoplasia?
Benign - new, autonomous growth but confined to a basement membrane, does not have the ability to metastasize
Malignant - new growth that breaks through the basement membrane and has the ability to metastatize and grow beyond the site of origin
What are the main components of tumors?
Parenchyma (neoplastic cells)
Stroma (reactive, with CT and BVs)
Nomenclature of tumors is based on parenchymal component but growth and spread are dependent on the stroma
What are the names for the following benign neoplasms?
Glandular epithelium
Smooth muscle
Skeletal muscle
Fibrous tissue
Adipose tissue
Adenoma
Leiomyoma
Rhabdomyoma
Fibroma
Lipoma (malignant form would be a liposarcoma)
What are the terms for the following malignant forms of neoplasia?
Epithelial (two forms)
Mesenchymal
Lymphoid
Melanocytic
Primitive
CNS glial
Carcinoma (adenocarcinoma for glandular, squamous cell carcinoma for epithelial)
Sarcoma
Lymphoma
Melanoma
Blastoma
Glioma
Which forms of neoplasia “sound” benign but are actually malignant?
Melanoma
Lymphoma
Gliomas (astrocytoma, glioblastoma)
What are the general characteristics of benign neoplasms?
Slow growth, usually well circumscribed, sometimes capsulated, look like tissue of origine at the microsocopic level.
What can benign neoplasms do?
Grow slowly and do no harm
Impinge on local, sometimes vital structures
Produce hormones or other substances
Cause cosmetic problems
Grow back (recurrent)
Be associated with other syndromes and physiologic phenomena
What are the general characteristics of malignant neoplasms?
Growth may be slow or rapid
Ill-defined
Non-encapsulated
Microscopic features vary
Break through basement membrane and “invade”–can spread and metastatize
What are the different forms of epithelial neoplasms and where are they generally found?
Squamous cell carcinoma - skin and mucosal surfaces
Adenocarcinoma - GI tract, liver, lung
Small cell carcinoma - lung, prostate
What is observed histologically with carcinomas?
Cells lose their architecture, become hyperchromatic (very dark), increase in nuclear size and irregularities in nuclear membrane
What are the different levels of differentiation in the microsscopic appearance of carcinomas?
Well differentiated - looks similar to normal epithelium but is slightly out of place
Moderately differentiated - looks somewhat like normal epithelium
Poorly differentiated - not like normal epithelium at all but is still a carcinoma
Undifferentiated - cannot be distinguished histologically alone
What are some examples of sarcomas and where do they occur?
Leiomyosarcoma - soft tissues and uterus (rare)
Rhabdomyosarcoma - head and neck, soft tissues, vagina
Liposarcoma - soft tissues, retroperitoneum
Fibrosarcoma - soft tissues
What are some examples of hematopoietic neoplasms?
Myeloid
Lymphoid - Hodgkin lymphoma, Non-Hodgkin lymphoma (B/T cell neoplasms)
What are melanomas and where do they arise from?
Derived from neural crest cells
Arise on skin (sun-exposed, usually), but can also arise in a variety of organs
Horizontal and vertical growth on skin
Moles that are asymmetric, colorful and with irregular borders are worrisome
What are the different forms of non-neoplastic cell proliferation and what are their general characteristics?
Hyperplasia occurs when there is an increase in the normal number of cells, abates in the presence of specific stimuli
Metaplasia occurs when there is proliferation of cells not characteristic of the site, reverts to the normal cell phenotype in the absence of stimulus
Dysplasia occurs withh disorderly growth and proliferation of cells, is a precursor to cancer and a component of a multistep process towards invasive disease
Neoplasia = new growth, usually interchangeable with “tumor”
How does dysplasia arise?
Through a stepwise progression of accumulating genetic alterations
Microscopic changes can be seen within the epithelial surface, such as loss of polarity at the basement membrane
Dysplasia by definition is confined to the basement membrane
What histologic changes are observed in dysplasia?
Disorderly growth and lack of maturation
Loss of polarity
Overlapping cells
Nuclear enlargement, membrane irregularity
What is occurring in desmoplasia?
Tumor parenchymal cells stimulate a prominant CT response–significant fibrous tissue makes the tumor feel firm and non-mobile.
How are malignant tumors graded?
Based on differentiation (well or poorly), nuclear pleomorphism (how atypical?), tumor necrosis (fast growth may lead to tumor cell death), and mitotic activity (can be observed histologically)
Grade is based on either low or high, or Grades I-III
Low grades “behave” better (more predictable growth)
How is tumor staging accomplished?
Via the TNM system:
T = tumor size, location
N = involvement of lymph nodes
M = presence of metastasis
How can malignant tumors spread?
Invasion of surrounding tissue (basal cell carcinoma on face invading into orbital fossa)
Via lymphatics (breast carcinoma to axillary lymph nodes)
Via bloodstream (hematogennous) to distant organs
Within the body cavity (seeding)
