Neoplasia Flashcards
What is neoplasia?
- “new growth”
- benign or malignant
- oncology = study of tumours or neoplasms
- cancer = malignant neoplasia
- benign neoplasms are not cancer!
Components of a tumour (2)
1) parenchymal cells/neoplastic cells (determines classification and biologic behaviour)
2) Reactive stroma (plays key role in determining growth and spread of tumour; desmoplasia = occurs surrounding neoplasm, causing dense fibrosis/scar tissue)
Benign and Malignant tumours (features of each)
Benign:
- Remains localized (does not invade into surrounding tissues/organs; doesn’t metastasize to other parts of body)
- Usually amenable to surgical removal
- Patient usually survives
Malignant:
- Has the capacity to invade into surrounding tissues/through the basement membrane
- Has the potential to metastasize to different locations in the body
Classification of tumours (4)
- Benign or Malignant
- What body site/organ of origin
- What tissue type (epithelial, mesenchymal)
- What cell type (squamous, glandular)
Epithelium
- lines external and internal surfaces
- cells closely packed together and polarized
- classified by 1) cell shape 2) cell layers
- attached to connective tissue through basement membrane
Mesenchymal
- from embryological layer, from mesoderm
- makes connective tissue (cartilage, bone, fat, blood cells)
- loose and dense fibrous tissue
- made up of cells and extracellular material
- endothelial cells
Nomenclature for benign tumours
Benign mesenchymal tissue tumours:
- oma
Benign epithelial tissue tumours:
1) adenoma
- benign tumour arising from gland or lining of gland (doesn’t have to form a gland, although some do)
2) papilloma
- benign tumour composed of projections with fibrovascular core covered in epithelium
3) cystadenoma
- benign tumour that forms a cystic mass
Nomenclature: name each type of tumour BENIGN: fat cartilage bone blood vessels smooth muscle striated muscle glands/ducts squamous transitional (urinary tract)
- lipoma
- chondroma
- osteoma
- hemangioma
- leiomyoma
- rhabdomyoma
- adenoma
- papilloma
- cystadenoma
- squamous cell papilloma
- transitional cell papilloma
Nomenclature for malignant tumours
mesenchymal tissue: sarcoma
epithelial tissue: carcinoma
- when unknown: undifferentiated malignant tumour, tumour of unknown primary…
Nomenclature: name each type of tumour MALIGNANT: fat cartilage bone blood vessels smooth muscle striated muscle glands/ducts squamous transitional (urinary tract)
- liposarcoma
- chondrosarcoma
- osteosarcoma
- Angiosarcoma
- leiomyosarcoma
- rhabdomyosarcoma
- adenocarcinoma
- papillary carcinoma
- cystadenocarcinoma
- squamous cell carcinoma
- transitional cell carcinoma
Nomenclature
- primitive malignant neoplasms
- blastoma
- typically pediatric malignant neoplasms showing primitive/embryonal history
- e.g. nephroblastoma (Wilm’s tumour)
Nomenclature:
- mixed tumours
- benign pleomorphic adenoma of salivary gland
- malignant mixed mullerian tumour (MMMT, carcinosarcoma): mix of endometrial carcinoma and sarcomatous carcinoma
- teratoma (monster tumour: more than one germ lines, benign or malignant, from germ cells)
Nomenclature exceptions and eponymous neoplasms
malignancies with benign sounding names:
- Lymphoid tissue: Lymphoma
• Melanocytes: Melanoma
• Mesothelial cells: Mesothelioma (pleural space in lungs)
• Germ cells: Seminoma/Dysgerminoma
• White blood cells: Leukemia
• CNS: Astrocytoma, oligodendroglioma, etc.
Eponymous Neoplasms
• Ewing’s sarcoma (bone malignancy in younger ppl)
- Kaposi’s sarcoma (malignant, blood vessels)
• Warthin’s tumour (salivary gland, benign)
- Brenner tumour (ovary, usually benign)
Congenital benign tumours
Hamartoma
• Disorganized but benign mass of tissue composed of
cells indigenous to that site
Choristoma (gastric epithelium in intestine)
• A heterotopic rest of normal tissue at an abnormal
location
• Usually a congenital anomaly of little if any significance
Polyp (bump above epithelium) (benign, malignant, or dysplastic) (lots of polyps in the colon)
• A macroscopically visible projection above a mucosa
surface (may be benign or malignant)
E.g., Tubular adenoma of colon:
• Benign tumour of colonic glandular epithelium by
nomenclature rules
Actually a low‐grade dysplastic lesion
• Clinical behaviour is benign at this stage, but has
potential to evolve into colonic adenocarcinoma
(so nomenclature is wrong; nomenclature says benign, but it can become malignant, so it’s wrong)
Characteristic differences of benign and malignant tumours
- Rate of growth
- Precursor lesions
- differentiation and anaplasia
- local invasion
- metastasis
