Electron microscopic examination of the stromal collagen surrounding the tumor mass of basal cell epitheliomas of the skin revealed severe degenerative changes that led to disappearance of the normal pattern of the dermal collagen. In most cases, a complete disappearance of the dermal collagen took place and resulted in the formation of a band-like clear space. Electron microscope examination showed this space to be filled with ill-defined, amorphous substances.
Basal laminae delimiting the tumor islands were also abnormal. They were swollen in some areas, thinned out in others, and often interrupted or absent. Segment-long-spacing collagen crystallites reconstituted from tropocollagen treated with basal cell epithelioma homogenate (crude enzyme) were often cleaved at the β22 locus, namely, 75% from the A end and 25% from the B end of the whole molecule. It is postulated that the clear space surrounding basal cell epithelioma parenchyma is produced by the degradation of dermal collagen, initially by specific collagenase and perhaps subsequently by other proteases.
This is Paper 2 of 2 papers of a series, entitled “Collagenolytic Activity of Basal Cell Epithelioma of the Skin.”