Correlation of altered penile ultrastructure with clinical arterial evaluation.

We investigated the ultrastructural changes in the penile erectile tissue from 32 consecutive patients who underwent penile prosthesis implantation. Because most of the patients had undergone papaverine injection with or without duplex ultrasonography, we compared these results with the electron microscopic findings. In patients with a good arterial response and full erection after papaverine injection the ultrastructural findings were similar to those reported in normal men. In patients with moderate arterial disease a distinct increase in mitochondria with aggregation and cytoplasmic vacuolization in smooth muscle cells was noted. These findings could be interpreted as an active cellular attempt to respond to the altered environmental and nutritive situation. In patients with severe arterial insufficiency the cellular structure was markedly altered, the number of intracavernous smooth muscle cells was reduced and the density of the connective tissue separating individual cells was increased. These changes in the smooth muscle cells consisted of contour irregularity with fragmentation and loss of the basal lamina. The cytoplasm was largely devoid of contractile elements. The nuclei tended to be pleomorphic with unevenly distributed chromatin. The endothelium was also altered significantly in this group. A careful clinical evaluation of penile arterial function should be performed in all patients undergoing penile arterial or venous corrective surgery. If doubt remains, a penile biopsy may be indicated.