neoplasm I Flashcards
neoplasma
-An abnormal mass of tissue, the growth of which
exceeds and is uncoordinated with that of the
normal tissue and persists in the same excessive
manner after cessation of the stimuli which
evoked the change. (Willis)
-autonomous growth: go by themself
-altered architecture, irreversible
tumor
swelling, neoplasm
oncology
scientific study of neoplasm
cancer
specific for a malignant neoplasm
characteristic features of neoplasm
-new growth of cells: from existing tissue
-cell proliferation without control
-serves no useful function
-lacks organization and arrangement
-continues to grow after evoking stimulus is
removed
hyperplasia
in normal arrangement
-reversible; proliferation ceases when evoking stimulus is
removed
metaplasia
-replacement of one fully differentiated cell type by another fully differentiated cell type
*reversible; proliferation ceases when evoking stimulus
is removed
benign cells
more organized than malignant
-1 kind of cell
dysplasia
-pathologic alteration in cell size, shape, and organization
-occurs primarily within the epithelium, but does not involve
the entire thickness of this layer
-may be reversible with removal of evoking stimulus
-loss of cellular uniformity, architectural organization
carcinoma in situ
- marked dysplastic change involving the entire thickness of the epithelium
- cells have completely replaced normal tissue, not invaded yet
- very early cancer
- pre-invasive malignant neoplasm
benign neoplasm
- autonomous growth, irreversible
- altered, but regular architecture
- monomorphic cells
- delimited from surrounding tissue by basement membrane, capsule, etc. – i.e., NOT invasive
- does not become malignant
Malignant neoplasm (cancer)
- autonomous growth, irreversible
- irregular architecture
- pleomorphism, anaplasia: look different, increased nucleus
- invasive, capable of metastasis
- very damaged cells
- unstable, continue to change
all neoplasms are
clonal proliferation
exceptions in neoplasm clonal proliferation
- teratoma
- mixed cell neoplasm
Teratoma
-parenchyma composed of multiple tissues (epithelial
and mesenchymal) derived from multiple embryonic
germ cell layers
-arise from totipotential cells
mixed cell neoplasm
-parenchyma is composed of epithelial and
mesenchymal cells
-derived from a single embryonic germ cell layer
behavioral characteristics: Benign
-well delimited: often encapsulated by fibrous connective
tissue
-well differentiated: better differentiated than malignant
neoplasms in terms of
*cell morphology
*tissue architecture
-function
-do not metastasize
-slowly and expansively growing
-do not recur following surgical excision
behavioral characteristics: Malignant
-locally invasive, destructive, progressive
-usually less differentiated than benign neoplasms
-may metastasize
-rapidly growing: grow more rapidly than most benign
neoplasms
-rate of growth generally correlates with the degree of
differentiation
-well differentiated neoplasms tend to grow slowly
-poorly differentiated neoplasms tend to grow rapidly
-may recur following surgical excision
biggest problem with benign tumors?
over growth, get big and can compress things
-in brain: bad thing
difference in margins of benign versus malignant
benign: regular, well tolerated
malignant: irregular
difference in metastasis of benign versus malignant
benign: NO
malignant: yes
difference in growth ratess of benign versus malignant
B: slow
M: fast
difference in recurrence after excision of benign versus malignant
B: No
M: yes
components of neoplasms
parenchyma: proliferating neoplastic cells
stroma: supporting tissue
parenchyma in a neoplasm
- cell of origin
- determines the biological behavior of the tumor
- neoplasms named based on their parenchymal cell type
stroma in a neoplasm
-composed of connective tissue, blood vessels +/-
lymphatics
-stimulation of surrounding stroma: desmoplasia
-grossly firm consistency (scirrhous)
-scirrhous: adjective for breast or colon cancer
tissues of origin
- Mesenchymal cells (Mesoderm)
- synovium, mesothelium, meninges
- muscle
- endothelial cells & related tissue (blood vessels)
- blood cells & related cells
- epithelial cells
tissue of origin: mesoderm
- connective tissue & derivatives (mesoderm):
- fibrous connective tissue
- adipose tissue
- bone, cartilage
tissue of origin: epithelial cells (ectoderm, endoderm)
- skin
- gastrointestinalepithelium
- glands / ducts
- respiratory, renal tubular, and transitional epithelium
- neuroectoderm
- hepatocytes
- placenta (trophoblasts)
nomenclature of benign neoplasms
-mesenchymal
cell of origin + “-oma”
-epithelial (glandular)
cell of origin / structure + “adenoma”
patterns for benign neoplasms
- Spherical masses in solid tissues
- Papillomas – epithelia
- Polyps – epithelia surrounding lumina (GI, ducts)
nomenclature of malignant neoplasms
-mesenchymal cell of origin + “-sarcoma” -epithelial (non-glandular) cell of origin / structure + “carcinoma” -epithelial (glandular) cell of origin / structure + “adenocarcinoma”
non-neoplasms
- Choristoma: outside tissue, GI tissue outside of GI
- Hamartoma: lung tissue, liver tissue, in normal tissue
- tissues are not neoplasmic,
exception for neoplasm nomenclature
- Melanoma: malignant skin tumor
- Seminoma: benign tumor of testicles
- Lymphoma:
- Hepatoma: tumor of liver
microscopic features of benign
well differentiation
homogenous
microscopic features of malignant
un or poorly differentiated
anaplasia
pleomorphism
anaplasia
1.Cellular pleomorphism
2.Abnormal architecture – loss of polarity,
differentiated features
3. Nuclear features
4. Cytoplasmic features
nuclear features of anaplasia
- hyperchromasia
- increased nuclear: cytoplasmic ratio
- increased, enlarged nucleoli
- increased, bizarre, mitotic figures
cytoplasmic features of anaplasia
-basophilia
the rate of a neoplasm
-In general, the rate of growth of a neoplasm correlates with the degree of differentiation: less differentiated neoplasms tend to grow more rapidly than well differentiated neoplasms.
is a benign neoplasm local invasion or expansive?
-expansive (non-infiltrative) growth
-well demarcated from the surrounding tissue
-capsule formation: compressed connective tissue
(stroma of parent tissue) accumulates as surrounding
tissue atrophies from pressure of expanding mass
is a malignant neoplasm local invasion or expansive?
- infiltrative growth, with destruction of the surrounding tissue
- poorly demarcated from the surrounding tissue
- +/- capsule formation, often with partial encapsulation
what are the two criteria for differentiating benign versus malignant
-Metastasis and local invasion are the two most reliable criteria for differentiating benign and malignant neoplasms
what does carcinoma in situ
-display the cytologicfeatures of malignancy without invasion of the basement membrane.
routes of metastasis
- lymphatics
- Hematogenous
- Seeding of body cavity
hematogenous metastasis
- Principle (sole) route for sarcomas
- Metastasis to liver, lungs, brain - Secondary route for carcinomas
what is the principal/initial route for metastasis?
lymphatics
