This is an elevation of the skin which has in its marginal parts branching processes extending out. There is evidently considerable contraction and dragging produced by the central tumour and the radiating processes, so that the skin is puckered around as in the case of a contracting cicatrix. The lesion has many of the characters of a definite tumour. It is composed, in the fully developed state, of dense connective tissue which may be unduly cellular. The new-formation has its seat in the deeper layers of the cutis, and it is stated that the papillary layer is intact. In the earlier stages it consists mainly of spindle cells, and Virchow therefore regarded it as a sarcoma. The analogy to the sarcoma is supported by the fact that the tumour recurs on removal. The most common site of keloid is the front or back of the chest, but it is found in other parts.

The name False keloid is sometimes used to designate a condition which occurs in Scars. A localized thickening, usually in the midst of a large cicatrix, as from a burn or an ulcer, presents itself, and there are raised processes passing out from it as in the true keloid. This is commonest in tubercular subjects.