[A] 1.75 Metastasis Flashcards
What is metastasis?
Cells coming from the primary tumour will reach other organs in the body
- Cells then adhere and start to proliferate
- Develop autonomous, secondary neoplasia
- Serve as a site of new metastatic activity → Generalisation
Metastasis: Overview
- Most important factor of prognosis
- Usually causes the death of the patient (not the primary tumour)
Give the classifications of metastasis
- Local/peritumoral (next to the tumour, in the original tissue)
- Regional (In sentinel lymph nodes)
- Distant
Anaplastic metastasis
- Usually, the metastatic tissue is the same as the primary neoplasia
- Sometimes atypia occurs
Prosoplasia
Metastasis is better differentiated than that of anaplastic metastasis
Give the routes of metastasis
- Hematogenous
- Lymphogenous
- Lymphohaematogenous
- Intracanalicular (Implantation/inoculation)
- Diaplacentar
Hematogenous metastasis
Via circulation
- Characteristic to sarcomas
- Usually invades veins
- 5 types:
- Vena cava type
- Vena portae type
- Vena pulmonalis type
- Vena hepatica type
- Paravertebral type
Vena cava type metastasis
Right side of the heart → Lungs
Vena portae type metastasis
→ Liver capillary system
Vena pulmonalis type metastasis
Primary lung tumour to left side of heart → Large circulation
Vena hepatica type metastasis
Primary liver tumour → Caudal vein → Lungs
Paravertebral type metastasis
Retrograde
Through plexus venosus paravertebralis → Vertebral venous plexus → Vertebrae, skull, limbs
Lymphogenous metastasis
Via lymphatic vessels
- Characteristic to carcinomas
- Physiologically, lymphatic circulation is unidirectional
Steps of lymphogenous metastasis
- Sentinel lymph node
- Cells reaching the lymph node either die or proliferate
- Micro-/macrometastasis
During lymphogenous metastasis, biopsy of the sentinel lymph node will show…
Staging
Skipping metastasis
When a regional/sentinel lymph node is skipped
Implantation metastasis
Tumour bursts into serosal cavities → Implanting on serosal layers
E.g :
- Ovary cystadenocarcinoma rupture
- GI neoplasia
- Bronchoalveolar carcinoma
Intracanalicular metastasis
Nerve tissue tumours can reach liquor (CSF)
- Giving intracranial & intraspinal metastasis
Inoculation metastasis
Into surgical site or near tissues
Generalisation
- Cell population develops from a single cell’s mutation
- Genetic instability increases with time
- Ability to metastasise depends on:
- Growth rate
- Vascularisation of the tumour
- Intravasation
Intravasation: Overview
Active / Passive
- Most cells die reaching the vessels
- Those that survive adhere to the vessel wall as an embolus (with the assistance of CAMs)
- Actively- Endothelial trauma, gap on the wall
- Passively - Tumour embolisation
- Followed by extravasation, implantation and proliferation
Intravasation: Mechanism
- Passive - Due to fast-growth → Tumour is ‘pushed’ into vessels
- Active - Change in relationship between neoplastic cell & ECM (Adhesion)
- Motility of cells increase
- They change places (Migration)
- ECM is lysed (Proteolysis)
Adhesion, motility/migration, proteolysis
- Cell-to-cell & Cell-to-ECM connections
- CAM: Cellular adhesion molecules will provide adhesion
- If adhesion changes, the connection will be loose → Invasion ability
- Motility of cells (by change of cytoskeletal elements)
- Proteolysis via Matrix metalloproteases
- Lysis of ECM, release of growth factors
List the cellular adhesion molecules (CAMs)
- Cadherins
- Selectins
- Immunoglobulins
- Integrins
