PHED-4547EL Lecture Notes - Lecture 7: Benign Tumor, Neoplasm, Dysplasia
27 Apr 2020
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Labile cell populations: continually divide, ex: cells in the gut. Stabile cell populations: little cell division, but can be renewed, ex: hepatocytes. Permanent cell populations: little or no ability to divide, ex: cardiac myocytes. Inappropriate growth of cells: not subject to normal control mechanisms that regulate cell growth and differentiation. Tumour: benign or malignant growth serves no normal function, not under homeostatic control. Dysplasia: localized areas of dysregulated growth. Solid: tumour is embedded in host tissue. Well-circumscribed: tumour has a clear border. Grade: how closely neoplasm resembles host tissue. Benign: growth rate: slow, growth character: expansion, tumour spread: remains localized, well-circumscribed, cell differentiation: well-differentiated cells (resembles cells of host tissue low grade) Malignant: growth rate: rapid, growth character: infiltrates host tissue, tumour spread: metastasis by bloodstream or lymphatic channels (primary to distant site, cell differentiation: poorly differentiated cells (high grade) Secondary site: site of growth following metastasis. Polyp or papilloma: benign, tumour that projects from epithelial surface, could become malignant.
