Chapter 5
Hyperplasias
and
Neoplasms
Review of Structure and Function
• All cells develop from the fertilized ovum
Review of Structure and Function
• Cell division continues into specialized cells
including:
– Labile Cells
– Stable Cells
– Epithelial Cells
– Connective Tissue Cells
– Muscle Cells
– Nervous tissue Cells
Hyperplasia and Hypertrophy
• Hyperplasia and hypertrophy are exaggerated
responses to a growth stimulus
• This can be a normal response to the body’s
demands.
Metaplasia and Neoplasia
• Metaplasia is the replacement of one tissue
type with another.
– This can be a normal response, or a
pathologic change.
• Neoplasia is similar to hyperplasia in that they
are both increased cell proliferation
– The difference is neoplasia is cell
proliferation in the absence of a stimulus.
Hyperplasia and Neoplasia
• The masses produced by these processes
cannot be distinguished from one another
without a histological examination.
• Treatment for each is vastly different.
Remember, neoplasias are autonomous
growth, while hyperplasias will stop growing
once the stimulus is removed.
Classification of Neoplasms
• Typically put into one of three categories
– Benign
– Malignant
– Uncertain malignant potential
Benign Neoplasms
• Benign neoplasms generally are localized, and
remain in the tissue in which they originated
• These are a single mass discrete from the
surrounding tissue.
Benign Neoplasms
• They usually have a fibrous rim or capsule
around them, which makes them easier to
excise.
• The cells closely resemble the cells of origin
Malignant Neoplasms
• Malignant neoplasms are more likely to
spread to entirely different sites, or invade
nearby structures.
• Metastasis often occurs through the lymph
nodes.