We report 2 cases of primary impotence due to a congenital defect in the compliance of the sinusoidal spaces secondary to fibrosis and atrophy of the smooth muscles. Both patients were young adults at presentation. Diagnosis of this rare entity was achieved by penile Doppler ultrasound and cavernosometry/cavernosography of the cavernous bodies. Both patients underwent placement of a penile prosthesis, during which biopsy samples of the cavernous tissue were obtained, and diagnosis was confirmed by light and electron microscopy.