Session 9: Neoplasia I

Question 1

define neoplasms and their histological appearance

Answer 1

Benign: abnormal growth of cells that persists after initiating stimulus is removed

-> appears rounded under an EM due to pushing growth, remains at site of origin

Malignant: abnormal growht of cells that persists after initiating stimulus is removed AND invades and spreads to distant sites

-> irregular mass due to infiltrative growth adges, may spread to distant site with a secondary growth (metastasis)

Question 2

Desc. heirarchy of tumours

Answer 2

a tumour is any clinically detectable swelling or lump

a neoplasm is one type of tumour

neoplasms can be benign or malignant, ie cancer

cancers have a primary site and a secondary site (the metastasis)

the primary site can be epithelial (carcinoma) or mesenchymal (sarcoma)

Question 3

define dysplasia and its relation to neoplasms

Answer 3

dysplasia is an abnormal maturation of cells in a tissue

it potentially is reversible but can lead to cancers

Question 4

genetic alterations in neoplasms

Answer 4

affects: proto-oncogenes (become abnormally activated to form oncogenes that favour neoplasm formation

tumour suppressing genes (inactivated so no longer suppress neoplasm formation)

Question 5

explain monoclonality of neoplasms and reasoning behind it

Answer 5

cell population is descended from a common ancestor cell

We know because: the G6PD gene codes for heat stable and heat labile isoenzymes

in heterozygous women one allele is inactivated randomly in all the cells forming a patchwork of different isoenzymes

however, in tumours, only one isoenzyme is expressed therefore monoclonal

Question 6

differences between neoplastic and normal cells

Answer 6

resistant to anti-growth signals, self sufficient growth signals, grow indefinitely, induce angiogenesis, invade and produce metastases

Question 7

compare benign/malignant neoplasms

Answer 7

both vary in size and shape

minimal/minimal to marked pleomorphism

low/low->high mitotic count

mitoses have normal/abnormal forms

well/well->poorly differentiated

Question 8

naming neoplasms based on benign/malignant

Answer 8

benign: oma, if in glands -> adenoma
malignant: epith -> carcinoma (in-situ or invasive), stromal -> sarcoma, glands -> adenocarcinoma

Question 9

naming CT neoplasms: SMC, fibrous, bone, cartilage, fat, nerve, nerve sheath, glial cells

Answer 9

SMCs: leiomyoma

fibroma

osteoma

chrondroma

lipoma

neurofibroma

neurilemmoma

(malignant) glioma

Question 10

naming blood, germ cell and precursor cell neoplasms

Answer 10

blood: always seen as malignant, lymphoid tiss. (usually lymph nodes -> B/T lymphoma -> hodgkins (orderly spread from one node to another, systemic symptoms following advanced disease state) or non hodgkins (anything but the above)
haematopoietic: leukaemia

malignant plasma cell neoplasm in bone marrow is myeloma and destroys adjacent bone

Germ cell: testes: malignant teratome/seminoma, ovaries: benign teratoma (a dermoid cyst)

precursor: normally in children, called a -blastoma