EXTENSIVE CORPOREAL FIBROSIS AFTER PENILE IRRADIATION

A potent man with early signs and symptoms of Peyronie's disease 3 mon ths in duration received 1,200 rad of external beam radiation to the p enis and presented 5 months later with impotence. Physical examination revealed diffusely woody indurated corporeal tissue. Nocturnal penile tumescence testing was abnormal and pharmaco-cavernosometry demonstra ted diffuse corporeal veno-occlusive dysfunction. Treatment by penile injections was unsuccessful. During penile prosthesis implantation bil ateral rubbery erectile tissue was encountered, requiring extensive bi lateral corporotomy and sharp corporeal tissue excision for prosthesis insertion. Histological analysis of excised corporeal tissue demonstr ated extensive corporeal fibrosis and arterial vasculopathy. Computer assisted color histomorphometry revealed that the mean percentage of t rabecular smooth muscle area to total erectile tissue area was 26.5 +/ - 15.8 (normal 40 to 52%). Immunohistochemical staining with desmin co nfirmed extensive fibrosis. The most likely explanation for severe cor poreal fibrosis is penile irradiation. The hypothesized mechanism of r adiation associated fibrosis is ionizing injury to the endothelial cel ls of the lacunar spaces and cavernous/helicine arteries, which induce d irreversible corporeal extracellular matrix structural changes. Peni le irradiation, like vascular disease and priapism, is a potential cau se of diffuse corporeal fibrosis.