22. Benign vs. Malignant vs. Metastatic Tumors

What are the characteristics of neoplasia?

B
M
M

• benign

• malignant

• metastatic

In general, how are benign tumors ultimately distinguished?

based on their invasiveness

Benign tumors typically have well ________ morphology. They similar structure to the cell or tissue of ________. They have little or no ________.

differentiated; origin; anaplasia

Benign tumors tend to be ________ growing, with ________ and ________ mitotic figures and ________ necrosis.

slow; rare; normal; little

Benign tumors are not ________ and frequently grow by ________ and _________ growth.

invasive; cohesive; expansile

What is often present with benign tumors?

capsule

separated from normal tissues by fibrosis connective tissue

encapsulation

Do benign tumors have metasiasis?

no

Malignant tumors have ________ differentiated morphologic features. The tissues of origin are sometimes ________. They also have variable degrees of ________.

poorly; unclear; anaplasia

Malignant tumors have ________ growth and ________ and ________ mitotic figures.

rapid; frequent; abnormal

Will malignant tumors have necrosis?

yes if there is poor blood supply

Malignant tumors have ________ invasion and are highly ________. A ________ is often absent or incomplete. ________ is sometimes present.

local; infiltrative; capsule; metastasis

What is the cellular criteria to determine malignancy?

W
C
C
A
A
K
M
M
M

• well/poorly differentiated (how much do cells look like they should)

• cellular pleomorphism (shape)

• cytomegaly

• anisocytosis (cell size)

• anisokaryosis

• karyomegaly

• mitotic figures

• multinucleation

• multiple nucleoli

When taking a mitotic count, number the mitotic figures per how many fields of view? Why is this important?

10; the more you look at, the better average you get because it is a more representative sample

spread to another site from the site of origin and can occur hematogenously through blood or through lymphatics

metastasis

True or false: An example of metastasis is when a mammary carcinoma goes to a lymph node or an osteosarcoma goes to the lungs.

true

What is this an example of?

metastatic tumor

What are the steps to metastases?

A
I
M
F
E
C

• adhesion

• invasion

• migration

• formation of emboli

• extravasation

• colonization

What occurs during adhesion? What does this mean?

detachment; first, the tumor cells must detach from the main tumor mass, penetrate the basement membrane, and enter the ECM

What occurs during invasion? What do the tumor cells use to achieve this?

basement membrane is breached in order to enter the ECM; matrix metalloproteinases

What is used during migration?

growth factors

During migration, tumor cells migrate through the ________ through alterations in the ________ of the cell and cellular ________ structures and secretion of autocrine ________ ________.

stroma; cytoskeleton; adhesion; growth factors

What are the routes of metastasis?

L
H
T

• lymphatic

• hematogenous (vascular)

• transcoelomic

metastatic cells can lie within distant or new sites until the right signals or set of environmental conditions occur

dormancy

What is responsible for most cancer mortality? What is it responsible for in humans?

metastasis; ~90% of cancer mortality from solid tumors

True or false: Metastasis is actually an inefficient process, as very few cells are capable of entering vessels or lymphatics for metastatic spread.

true

Lymphatic spread/ metastasis occurs most often with what tumor type?

carcinomas

During lymphatic metastasis, where does it often go to first?

draining lymphatics before distant sites

Hematogenous spread/metastasis occurs most often with what tumor type?

sarcomas

During hematogenous metastasis, are veins or arteries commonly used? Why?

veins; walls are much thinner than arteries, making them easier to penetrate

What is the common route of hematogenous metastasis?

veins → heart → capillary beds, particularly the lungs

Tumors which invade the portal vessels such as pheochromocytomas tend to metastasize to the ________ first.

liver

direct dissemination throughout a body cavity that commonly occurs with mesotheliomas or carcinomas and rarely sarcomatosis

transcoelomic metastasis

What would be an example of sacromatous spread?

ruptured splenic hemangiosarcoma, which can seed the abdomen

What are two specific tumor types that are the most common to spread via transcoelomic metastasis?

ovarian adenocarcinomas and pancreatic adenocarcinomas