Week 6 Neoplasm Flashcards
Define neoplasm
Clonal overgrowth of genetically abnormal cells with loss of normal growth control.
How do neoplasms occur?
Neoplasms occur when one cell acquires a genetic mutation that escapes cell proof-reading mechanisms. This cell begins to divide and will often acquire new mutations.
When is a neoplasm benign?
A neoplasm is benign when it remains localized and does not have metastatic potential. For instance, when it has not broken through the basement membrane.
What are the histological features of a benign neoplasm?
It is well differentiated with a defined edge. It has not invaded surrounding tissues.
When is a neoplasm malignant?
A neoplasm that has begun to invade surrounding tissues and has acquired the ability to metastasize to other organs.
Through what routes do metastases occur?
Vascular and lymphatic
What is an in situ neoplasm?
A proliferation of cells that have acquired the capabilities required to become invasive, but have not invaded past the basement membrane yet. Given enough time, all in situ neoplasms will become invasive.
What structure does an epithelial neoplasm need to break through in order to become malignant/invasive?
The basement membrane.
What is metastasis?
The spread of neoplastic cells to other tissues/organs. This occurs when the neoplasm invades blood vessels or the lymphatic system.
What are the histologic features of a malignant neoplasm?
Architectural: overgrowth, disorganization, destruction/necrosis (neoplasm is outgrowing its blood supply)
Morphological: Abnormalities in the nucleus, difference in mitotic rate, loss of cell-cell relationships
What is a neoplasm grade?
A measure of how abnormal neoplastic cells look compared to neighboring tissue under a microscope.
Grade and prognosis are not necessarily linked.
What does it mean when a neoplasm has a low grade?
A low grade neoplasm looks similar to normal tissue in the organ. It is called well differentiated and will likely grow and spread at a slower rate than high grade neoplasms.
What does it mean when a neoplasm has a high grade?
A high grade neoplasm looks very different from surrounding tissues. It is called undifferentiated and will often grow and spread more quickly.
What is the stage of a neoplasm?
An anatomic measure of the size and extent of the spread of a neoplasm. It is closely tied to prognosis. It takes into account the size of the primary tumor, lymph node involvement, and distant metastases.
Is grade or stage more important in neoplasms?
Stage is more important. It is linked to treatment types.
