This section is from the book "A Manual Of Pathology", by Guthrie McConnell. Also available from Amazon: A Manual Of Pathology.
Mucoid Or Myxomatous Metamorphosis is the conversion of cells and intercellular substances into mucin.
Mucin is insoluble in water, but will absorb it; is soluble in alkaline solutions, but is precipitated by weak acetic acid. When boiled with acids, will reduce Fehling's solution.
Either epithelial cells or the intercellular substances may undergo mucoid change. The latter is the more truly a metamorphosis.
It occurs in epithelial cells in all forms of catarrhal inflammation, in the cells of epithelial cysts, and in some carcinomata.
It is found in the interstitial tissues in both epithelial and connective-tissue growths, in some inflammatory conditions, and in myxedema.
The mucous membranes will be covered by a coat of thick, stringy, and viscid exudate. The underlying tissues may or may not show congestion.
Connective tissues will be more or less soft, slightly swollen, and will tear easily. If the condition is very much localized, cysts filled with mucin may be found. Three substances closely related are included under the heading of Myxomatous metamorphosis: mucin, pseudomucin, and paramucin, each one differing slightly from the others in its reaction.
The typical mucoid cell is the so-called "goblet-cell" that is found in the large intestine.