Of the various pathologic changes which may occur in the thyroid gland, that of colloid formation is the most frequent. In order, however, that this colloid formation may receive the title of struma colloides it is not sufficient that a little colloid material be found in the vesicles or follicles throughout the gland as this is often a physiologic condition, especially in later life, but the colloid formation must occur in a circumscribed area or areas, sharply defined from the normal gland tissue and independently of it.
Furthermore, as Wölfler states, there is in these cases an atypical new tissue formation, a budding of the gland tubules, so that what we really have is an adenoma, in the tubules of which the colloid material accumulates, leading to their distension: hence the name applied by Wölfler of adenoma gelatinosum. These new growths may be single or multiple, and when multiple may
HARRIS ML. STRUMA GELATINOSA—STRUMA COLLOIDES.. JAMA. 1896;XXVI(14):663-664. doi:10.1001/jama.1896.02430660015003d