The abnormal dermis in pyogenic granuloma. Histochemical and ultrastructural observations.

The connective and vascular tissues of pyogenic granulomas have been studied in lesions from forty-six patients. Twenty were studied histochemically, and five were examined ultrastructurally. Both tissues showed a wide range of maturity and cellular activity. The fibroblasts in particular showed evidence of increased synthetic activity. Intranuclear inclusion bodies, suggestive of altered synthetic activity, were found in the endothelial cells of four lesions. It is suggested that pyogenic granuloma arises from disordered growth of papillary dermis.