2 cases of eccrine spiradenoma were analyzed histologically and electron microscopically. In neither case true glandular structures could be found. On the submicroscopic level, 'lumina', as seen by light microscopic method, were found to be stroma islands containing fibrillar material, or cavities probably formed by cell decay. In case 2, submicroscopic examination revealed a considerable degree of cell and tissue alteration as intercellular edema, cellular shrinkage and phagocytic phenomenons. A striking finding was a marked dissociation of the stroma resulting in the formation of small units which were sometimes found to be phagocytized within tumor cells. These alterations are interpreted as a sign of regressive transformation of the tumor.