1. Lecture # 42 NEOPLASIA - 3 Dr
Lecture # 42 NEOPLASIA - 3 Dr. Iram Sohail Assistant Professor Pathology College Of Medicine Majmaah University

2. OBJECTIVES
Explain what is meant by local invasion
Explain metastasis

3. LOCAL INVASION
Benign
Remains localized at the site of origin
Do not infiltrate or invade
Slowly expand & mostly develop a fibrous capsule

4. But some benign lesions do not have capsule, like leiomyoma
Examples
Adenoma
Fibroma
But some benign lesions do not have capsule, like leiomyoma

5. Malignant tumors (cancer)
They infiltrate & invade
They cause penetration & destruction of surrounding tissue

6. No capsule
Microscopically, crab like feet penetrating the surrounding tissue

7. So it is necessary for the surgeon to remove the normal surrounding area of tissue along with the actual cancer.

8. METASTASIS
Development of secondary implants, discontinuous with the primary tumor
It is the most important property of malignant tumor.

9. Approximately 30% of newly diagnosed patients present with metastasis.
Mostly the larger and more anaplastic primary tumors have more tendencies to metastasize.

10. Malignant neoplasm spread by 3 pathways
Seeding within body cavities
Lymphatic spread
Hematogenous spread

11. Seeding within body cavities
When a tumor invades a natural body cavity.
Examples
Ovarian cancers spread
through peritoneal cavity.

12. Brain tumors (medulloblastoma, ependymoma) spread to the meninges through CSF (cerebrospinal fluid).

13. Lymphatic spread
Mostly carcinomas are spread by this route.
The lymph nodes & lymphatics involvement is depends upon the location of the tumor.

14. Examples
Carcinoma of lungs spread to the hilar lymph nodes.

15. Breast cancers are mostly metastasize to axillary lymph nodes.
All the metastatic cells eventually reach the thoracic duct through lymphatics.

16. Sentinel lymph node
A sentinel lymph node is the first lymph node in the regional lymphatic system that receives lymph from primary tumor.
We can identify this sentinel lymph node by injecting a blue dye.

17. Surgeons do the biopsy of sentinel lymph node to find out the extent of spread of tumor and the plan the further treatment.

18. In lymph nodes metastasis, the lymph nodes will be enlarged.
But lymph nodes enlargement can also occur in reactive (non – cancerous) conditions.

19. Hematogenous (blood) spread
Mostly sarcomas are spread by this route.
Veins are involved more commonly as compare to arteries.

20. The liver & lungs are the most frequently involved secondary sites in Hematogenous spread.

21. Mechanism of
Metastasis

22. Common examples of different metastatic tumors
Prostatic carcinoma ----spreads to -----bone

23. Lung carcinoma------spreads to-------brain & adrenal gland