Extensive corporeal fibrosis after penile irradiation.

A potent man with early signs and symptoms of Peyronie's disease 3 months in duration received 1,200 rad of external beam radiation to the penis and presented 5 months later with impotence. Physical examination revealed diffusely woody indurated corporeal tissue. Nocturnal penile tumescence testing was abnormal and pharmaco-cavernosometry demonstrated diffuse corporeal veno-occlusive dysfunction. Treatment by penile injections was unsuccessful. During penile prosthesis implantation bilateral rubbery erectile tissue was encountered, requiring extensive bilateral corporotomy and sharp corporeal tissue excision for prosthesis insertion. Histological analysis of excised corporeal tissue demonstrated extensive corporeal fibrosis and arterial vasculopathy. Computer assisted color histomorphometry revealed that the mean percentage of trabecular smooth muscle area to total erectile tissue area was 26.5 +/- 15.8 (normal 40 to 52%). Immunohistochemical staining with desmin confirmed extensive fibrosis. The most likely explanation for severe corporeal fibrosis is penile irradiation. The hypothesized mechanism of radiation associated fibrosis is ionizing injury to the endothelial cells of the lacunar spaces and cavernous/helicine arteries, which induced irreversible corporeal extracellular matrix structural changes. Penile irradiation, like vascular disease and priapism, is a potential cause of diffuse corporeal fibrosis.