3Neoplasia Outline Tumor nomenclature Tumor characteristics Differentiation and anaplasiaRate of growthLocal invasionMetastasis
4Neoplasia Outline Tumor nomenclature Tumor characteristics Differentiation and anaplasia
5Differentiation and Anaplasia Differentiation = how much the tumor cells resemble their cells of originwell-differentiated – closely resemblesmoderately-differentiated – sort of resemblespoorly-differentiated – doesn’t resembleBenign tumors are usually well-differentiatedMalignant tumors can show any level of differentiation
11Differentiation and Anaplasia Anaplasia = a state of complete un-differentiationLiterally, “to form (-plasia) backwards (ana-)”Misnomer! Cells don’t de-differentiate.Just means cells are very poorly-differentiatedAlmost always indicates malignancy
12Differentiation and Anaplasia Anaplastic cells show:PleomorphismHyperchromatic, large nucleiBizarre nuclear shapes, distinct nucleoliLots of mitoses, and atypical mitosesArchitectural anarchy
15Differentiation and Anaplasia Dysplasia = disorderly (dys-) growth (-plasia)“Dysplasia” is used to describe disorderly changes in non-neoplastic epithelial cells.Graded as mild, moderate or severe.Mild-moderate: usually reversibleSevere: usually progresses to carcinoma in situ (CIS).Next step after CIS: invasive carcinoma.
16Differentiation and Anaplasia Dysplastic cells show:PleomorphismHyperchromatic, large nucleiLots of mitosesArchitectural anarchy
17Q. Wait a minute, “dysplasia” sounds suspiciously similar to “differentiation” – what’s the difference?
18Q. Wait a minute, “dysplasia” sounds suspiciously similar to “differentiation” – what’s the difference?A. Both terms describe whether cells look normal or not!But:“differentiation” is only used with neoplastic cells, and “dysplasia” is only used with non-neoplastic cells!“dysplasia” is only used with epithelial cells, but “differentiation” can apply to any cell type.
19Non-neoplastic epithelial cells carcinoma in situmild dysplasiamoderate dysplasiasevere dysplasiaNeoplastic cellswell-differentiatedmoderately-differentiatedpoorly-differentiatedanaplastic
30Neoplasia Outline Tumor nomenclature Tumor characteristics Differentiation and anaplasiaRate of growth
31Rate of Growth Generalizations Malignant tumors grow faster than benign ones.Poorly-differentiated tumors grow faster than well-differentiated ones.Growth is dependent on:Blood supplyHormonal factorsEmergence of aggressive sub-clones
32Growth fraction = cells that are actively dividing Rate of GrowthGrowth fraction = cells that are actively dividingAge of tumorEarly on (subclinical), GF high.Later (clinically detectable), GF low.Type of tumorLeukemias, lymphomas, small-cell lung cancer: high GFBreast, colon cancer: low GFImportant for treatmentHigh GF tumor: treat with chemotherapy/radiationLow GF tumor: treat by debulking
39Neoplasia Outline Tumor nomenclature Tumor characteristics Differentiation and anaplasiaRate of growthLocal invasion
40Local Invasion Benign tumors Malignant tumors Stay where they are. Can’t invade or metastasize.Usually encapsulated.Malignant tumorsInfiltrate, invade, destroy surrounding tissue.Then metastasize to other parts of body.Not encapsulated.
50MetastasisMetastasis = development of secondary tumor implants in distant tissuesHalf of all patients with malignancies have mets at the time of diagnosis!!Metastasis depends on:Type of tumorSize of tumorDegree of differentiation of tumor
59Three ways tumors metastasize MetastasisThree ways tumors metastasizeSeedingLymphatic spreadTumor spreads to local lymph nodesSentinel lymph node firstMoves through thoracic ductEmpties into subclavian veinCarcinomas like to spread this way
61Three ways tumors metastasize MetastasisThree ways tumors metastasizeSeedingLymphatic spreadHematogenous spreadVeins are easier to invade than arteriesLiver and lungs are most common metastatic destinationsSome tumors like other sites better:prostate → bonemost lung cancers → adrenals, brainSarcomas like to spread this way (but so do carcinomas)