Week 3: Neoplasia I

Question 1

What is non-neoplastic cell proliferation?

Answer 1

Controlled cell growth induced by a stimulating agent, abates following removal of stimulating agent

Question 2

What is neoplastic cell proliferation?

Answer 2

Unregulated cell growth which occurs and persists in the absence of an inducing agent?

Question 3

What is a tumor?

Answer 3

Swelling generically used to describe a neroplastic process. Tumors are not specifically benign or malignant.

Question 4

What are the differences in tumor clonality?

Answer 4

Neoplastic cells are monoclonal in origin (come from a single cell

Non-neoplastic cell proliferation is generally polyclonal

Question 5

What are the two forms of neoplasia?

Answer 5

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

Question 6

What are the main components of tumors?

Answer 6

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

Question 7

What are the names for the following benign neoplasms?

Glandular epithelium

Smooth muscle

Skeletal muscle

Fibrous tissue

Adipose tissue

Answer 7

Adenoma

Leiomyoma

Rhabdomyoma

Fibroma

Lipoma (malignant form would be a liposarcoma)

Question 8

What are the terms for the following malignant forms of neoplasia?

Epithelial (two forms)

Mesenchymal

Lymphoid

Melanocytic

Primitive

CNS glial

Answer 8

Carcinoma (adenocarcinoma for glandular, squamous cell carcinoma for epithelial)

Sarcoma

Lymphoma

Melanoma

Blastoma

Glioma

Question 9

Which forms of neoplasia “sound” benign but are actually malignant?

Answer 9

Melanoma

Lymphoma

Gliomas (astrocytoma, glioblastoma)

Question 10

What are the general characteristics of benign neoplasms?

Answer 10

Slow growth, usually well circumscribed, sometimes capsulated, look like tissue of origine at the microsocopic level.

Question 11

What can benign neoplasms do?

Answer 11

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

Question 12

What are the general characteristics of malignant neoplasms?

Answer 12

Growth may be slow or rapid

Ill-defined

Non-encapsulated

Microscopic features vary

Break through basement membrane and “invade”–can spread and metastatize

Question 13

What are the different forms of epithelial neoplasms and where are they generally found?

Answer 13

Squamous cell carcinoma - skin and mucosal surfaces

Adenocarcinoma - GI tract, liver, lung

Small cell carcinoma - lung, prostate

Question 14

What is observed histologically with carcinomas?

Answer 14

Cells lose their architecture, become hyperchromatic (very dark), increase in nuclear size and irregularities in nuclear membrane

Question 15

What are the different levels of differentiation in the microsscopic appearance of carcinomas?

Answer 15

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

Question 16

What are some examples of sarcomas and where do they occur?

Answer 16

Leiomyosarcoma - soft tissues and uterus (rare)

Rhabdomyosarcoma - head and neck, soft tissues, vagina

Liposarcoma - soft tissues, retroperitoneum

Fibrosarcoma - soft tissues

Question 17

What are some examples of hematopoietic neoplasms?

Answer 17

Myeloid

Lymphoid - Hodgkin lymphoma, Non-Hodgkin lymphoma (B/T cell neoplasms)

Question 18

What are melanomas and where do they arise from?

Answer 18

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

Question 19

What are the different forms of non-neoplastic cell proliferation and what are their general characteristics?

Answer 19

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”

Question 20

How does dysplasia arise?

Answer 20

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

Question 21

What histologic changes are observed in dysplasia?

Answer 21

Disorderly growth and lack of maturation

Loss of polarity

Overlapping cells

Nuclear enlargement, membrane irregularity

Question 22

What is occurring in desmoplasia?

Answer 22

Tumor parenchymal cells stimulate a prominant CT response–significant fibrous tissue makes the tumor feel firm and non-mobile.

Question 23

How are malignant tumors graded?

Answer 23

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)

Question 24

How is tumor staging accomplished?

Answer 24

Via the TNM system:

T = tumor size, location

N = involvement of lymph nodes

M = presence of metastasis

Question 25

How can malignant tumors spread?

Answer 25

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)