Mucoid Degeneration

Introduction

• Mucoid degeneration is also known as mucinous or myxomatous degeneration.
• Mucoid degeneration involves changes in epithelial tissue or the extracellular matrix/ ground substance.
• An extracellular phenomenon of some specific cells.
  • Tend to show a bluish tinge in H&E stained sections.

Epithelium

• The specific cells involved in mucoid degeneration in the eptihelium are:
  • The goblet cells of wet mucous membranes.
  • The mucous glands themselves.
• This is not really a degeneration, but an increased production of mucin.
  • It is a beneficial reaction; the product
    • Is important as a lubricant.
    • Soothes inflamed surfaces.
    • Traps and dilutes harmful agents.
    • Carries specific antibodies against infectious agents.
    • Provides a means for removal of infectious agents.

Connective tissue

• Here, the mucin forms part of the ground substance between the fibroblasts that produce it.
• A disturbance in the metabolism of the fibroblasts under some circumstances,means the ground substance takes on a bluish hue in H&E sections.
• Mucoid degeneration in the heart valves of middle-aged and older dogs is a common example.
  • Causes endocardiosis.
    • A condition specific to the dog.