Neoplasia 2: Spread of Malignant tumors Flashcards
Explain how Malignant tumors invades ECM
- Tumor cell loses cell cohesion and detaches from rest of tissue by loss of Cadherin
- Attachement of tumor cell to laminin of basement membrane & fibronectin of ECM
- Degredation of ECM by Typer 4 collagenase & Cathepsin D
- Migration of tumor cell by pseudopodia using autocrine mobility factors
- Acquirement of negative charges on its surface to repel other cells —> loss of contact (cell to cell) inhibition
Enzymes used by malignant tumors to degrade ECM, & their function
- Type 4 collagenase: lysis of basement membrane
- Cathepsin D: lysis of interstitium
Explain how tumor gains mobility & pseudopodia
by tumor- derived cytokine= Autocrine motility factors
Order of BV from most penetrable to least penetrable by tumor
- Lymphatics
- Capillaries
- Venules
- (rarely) Arterioles
Explain who lymphatics are the most penetrable by tumors
due to lack of basement membrane
Describe fate of tumor emboli
- Most tumors emboli are destroyed by immune system
- Some adhere to platelets, protecting themselves from immune system
- They get impacted into small vessels, then adhere to endothelium, then cross the basement membrane, to reach & settle in a new site (homing)
Define organ tropism
Expression of adhesion molecules on the tumor cell whose ligands are expressed by endothelial & the metastic site, or chemokine receptors on the tumor cell
Examples of organ tropism
- Prostatic carcinoma spreads to bone
- bronchogenic carcinoma spreads to adrenal glands or brain
- Neuroblastoma to liver & bones
Routes of spread of tumor is divided into ____
- Direct (local) spread
- Distal spread= Metastis
define direct/local spread
progressive infiltration, invasion & destruction of surrounding tissue
Which type of tissue delays local spread of tumor
- Bone
- Cartilage
- elastic tissue
- fibrous tissue
Metastis is divded into ___
- Lymphatic spread
- Blood (hematogenous) spread
- Transcoelomic Spread
- Transluminal Spread
Lymphatic spread is more common in what type of Cancer
Carcinoma (than sarcoma)
gross pathology of tumor emboli of Lymph nodes
- Enlarged
- hard
- fixed
- painless
explain how lymphatic spread reaches hematogenous spread
tumor spreads in lymph to reach main lymphatic ducts (thoracic duct) —> Venous circulation—> blood
Definition of Lymphatic permeation
Solid columns inside lymphatics causing obstruction (no drainage) —> Lymphatic edema
which cancer shows lymphatic permeation (lymphatic edema)
Breast cancer
Clinical diagnosis of enlarged LN near primary neoplasm
- Doesn’t mean cancer has infiltrated the node
- may be due to necrotic products of the neoplasm & tumor antigens stimulates immunologic response in the node (Lymphadenitis)/ sinus histocytosis (macrophage accumulation at sinuses)
Define sentient lymph node
First regional lymph node receiving lymph from site of primary tumor
Explain how sentient LN is traced and studied
- Inject blue dye/ radiolabeled tracers near the site of tumor
- remove LN & study (biopsy) using frozen section
Most common organs affected by Hematogenous spread
- Liver
- Brain
- Lung
- Bone
LBLB
Explain how lung metastases come from blood spread
Emboli moves in systemic veins from organ to right side of the heart via Vena Cava —> Pulmonary arteries —> Lung Metastase
how does primary/metastic lung cancer spread to other organs
Emboli spreads through pulmonary veins to left side of the heart —> Aorta —> systemic arterial circulation
Emboli reach portal veins from GIT may cause Metastase in ___
Liver
Emboli that reaches hepatic vein may cause metastase in ___
Lungs (drains in IVC –> rt side heart –> pulmonary artery)
verterbaral metastase is common from what types of Carcinomas
- Prostate
- Thyroid
in what case is bone metastase osteosclerotic/osteoplastic (builds bone) instead of osteolytic (common), and why ?
prostate cancer
It secretes phosphate
gross picture of blood metastase
scateered rounded nodules with central umblication (depression) of variable sizes
Microscopic picture of blood metastase
resmbles primary tumor of ewhich they are derived
Define transcoelomic metastase
primary tumor from an organ surrounded by serous membrane to be implanted on serosal surface of other organ
macroscopic picture of transperitoneal metastase
peritoneal/ omental nodules with hemorrhagic ascites
Explain Kurkenberg tumors
Carcinoma of stomach or colon causes Bilateral ovarian metastase
cause of kurkenberg tumors is now believed to be ____
- retrograde lymphatic flow
- Blood spread
sites of CSF metastase
- Ventricles
- base of skull
- spinal cords
Example of translumenal spread
transitional carcinoma of renal pelvis is implanted in mucosa of urinary bladder
