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Neoplasia

Neoplasia. Why do we need a lecture about neoplasia?. 1- To understand patients better 2- To understand All neoplasms better 3- To nail the neoplasia questions on boards - This lecture covers: - the nature of benign and malignant neoplasms - how neoplasms start and grow

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Neoplasia

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  1. Neoplasia

  2. Why do we need a lecture about neoplasia? 1- To understand patients better 2- To understand All neoplasms better 3- To nail the neoplasia questions on boards - This lecture covers: - the nature of benign and malignant neoplasms - how neoplasms start and grow - Later lectures will cover: - the nature of specific neoplasms - how these neoplasms affect the patient

  3. Neoplasia Outline 1- Tumor nomenclature 2- Tumor characteristics 3- Epidemiology 4- Cancer pathogenesis

  4. * Tumor nomenclature 1- Definitions 2- Benign tumors 3- Malignant tumors 4- Mixed tumors 5- Confusing terms

  5. - Neoplasm = mass of tissue that grows excessively, and keeps growing even if you remove the stimulus that started it off! - Tumor = neoplasm - Benign tumor = innocent-acting tumor - Malignant tumor = evil-acting tumor *Tumor nomenclature - *Definitions

  6. Cancer = Latin for “crab”

  7. Definitions • Small • Slow-growing • Non-invasive • Well-differentiated • Stay localized • Large • Fast-growing • Invasive • Poorly-differentiated • Metastasize Benign Tumors Malignant Tumors

  8. The only indisputable quality of malignancy is metastasis! Benign tumors CANNOT metastasize; malignant tumors CAN. If it is metastatic, it MUST BE malignant.

  9. Benign vs. Malignant

  10. - Tumor nomenclature - Definitions -*Benign tumors

  11. Benign Tumors * Usually designated by adding “-oma” to cell type - adenoma– benign tumor arising from glandular cells - leiomyoma– benign tumor arising from smooth muscle cells - chondroma – benign tumor arising from chondrocytes * Other benign tumor names - papilloma – has finger-like projections - polyp – projects upward, forming a lump - cystadenoma– has hollow spaces (cysts) inside

  12. Thyroid adenoma Thyroid adenoma Normal thyroid

  13. Leiomyoma Chondroma

  14. Oral papilloma

  15. Colon polyp

  16. Ovarian cystadenoma

  17. - Tumor nomenclature - Definitions - Benign tumors -* Malignant tumors

  18. Malignant Tumors - Carcinomas – arise in epithelial tissue - adenocarcinoma – malignant tumor of glandular cells - squamous cell carcinoma – malignant tumor of squamous cells - Sarcomas – arise in mesenchymal tissue - chondrosarcoma – malignant tumor of chondrocytes - angiosarcoma – malignant tumor of blood vessels - rhabdomyosarcoma – malignant tumor of skeletal muscle cells

  19. Adenocarcinoma Squamous cell carcinoma

  20. Chondrosarcoma Angiosarcoma Rhabdmyosarcoma

  21. - Tumor nomenclature • Definitions • Benign tumors • Malignant tumors - * Mixed tumors

  22. Mixed Tumors - “Mixed” tumors show divergent differentiation - Examples - pleomorphic adenoma – glands + fibromyxoid stroma - fibroadenoma – glands + fibrous tissue -Not to be confused with teratomas

  23. Pleomorphic adenoma

  24. -Tumor nomenclature 1- Definitions 2- Benign tumors 3- Malignant tumors 4- Mixed tumors 5- *Confusing terms

  25. Confusing Terms 1- Malignant tumors that sound benign - lymphoma - mesothelioma - melanoma - seminoma 2- Non-tumors that sound like tumors - hamartoma – mass of disorganized indigenous tissue - choristoma – heterotopic rest of cells 3- Names that seem to come out of nowhere - nevus - leukemia - hydatidiform mole

  26. Nomenclature Neoplasm Benign Malignant Carcinoma Sarcoma

  27. Nomenclature Neoplasm Benign Malignant adenoma angioma rhabdomyoma Carcinoma Sarcoma

  28. Nomenclature Neoplasm Benign Malignant Carcinoma Sarcoma squamous cell carcinoma adenocarcinoma

  29. Nomenclature Neoplasm Benign Malignant Carcinoma Sarcoma angiosarcoma rhabdomyosarcoma

  30. Tumor Characteristics

  31. Neoplasia Outline - Tumor nomenclature - Tumor characteristics - Epidemiology - Cancer pathogenesis

  32. - Tumor nomenclature - Tumor characteristics : 1- Differentiation and anaplasia 2- Rate of growth 3- Local invasion 4- Metastasis

  33. - Tumor nomenclature - Tumor characteristics 1- Differentiation and anaplasia

  34. Differentiation and Anaplasia - Differentiation = how much the tumor cells resemble their cells of origin - well-differentiated – closely resembles - moderately-differentiated – sort of resembles - poorly-differentiated – doesn’t resemble - Benign tumors are usually well-differentiated - Malignant tumors can show any level of differentiation

  35. Thyroid adenoma (well-differentiated)

  36. Intercellular bridges

  37. Squamous cell carcinoma, well-differentiated Squamous cell carcinoma, moderately-differentiated Squamous cell carcinoma, poorly-differentiated

  38. Differentiation and Anaplasia Anaplasia = a state of complete un-differentiation Literally, “to form (-plasia) backwards (ana -)” Misnomer! Cells don’t de-differentiate. Just means cells are very poorly-differentiated Almost always indicates malignancy

  39. Differentiation and Anaplasia • Anaplastic cells show: - Pleomorphism - Hyperchromatic, large nuclei - Bizarre nuclear shapes, distinct nucleoli - Lots of mitoses, and atypical mitoses - Architectural anarchy

  40. Anaplastic carcinoma Abnormal mitoses

  41. Differentiation 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 reversible • Severe: usually progresses to carcinoma in situ (CIS). - Next step after CIS: invasive carcinoma.

  42. Differentiation and Anaplasia • Dysplastic cells show: • - Pleomorphism • - Hyperchromatic, large nuclei • - Lots of mitoses • - Architectural anarchy

  43. “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.

  44. Non-neoplastic epithelial cells carcinoma in situ mild dysplasia moderate dysplasia severe dysplasia Neoplastic cells moderately-differentiated poorly-differentiated well-differentiated anaplastic

  45. Dysplasia

  46. Normal glands

  47. Moderate dysplasia Mild dysplasia Severe dysplasia

  48. Normal squamous epithelium Moderate dysplasia Severe dysplasia

  49. Dysplastic epithelium Normal epithelium Invasive squamous cell carcinoma

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