Obstructive lesions of the lower urinary tract in the prune belly syndrome.

The prune belly syndrome is a well-recognized entity consisting of deficient abdominal musculature, cryptorchid testes, and urinary tract abnormalities most consistent with an obstructive phenomenon. However, an obstructive lesion has not been consistently identified in previously reported cases. Retrospective review of the autopsy files of The Johns Hopkins Hospital, Baltimore, identified 18 cases of prune belly syndrome occurring since 1945. In 13 cases, obstructive lesions in the lower urinary tract had been described grossly. A single case, in which the lower urinary tract had been preserved intact and subsequently serially sectioned as 8-micron sections taken at every 120 micron, demonstrated an obstruction consisting of two overriding urethral lumens connected only by a narrow channel. Reconstruction of the sections suggested that this represented a "kink" in a short segment of the prostatic urethra just above the membranous urethra, leading to the obstructive changes of bladder hypertrophy and dilatation, hydroureter, hydronephrosis, and renal dysplasia seen higher in the urinary tract. The results suggest that examination of the lower urinary tract in cases of prune belly syndrome by serial histologic sectioning of the intact unopened prostatic and penile urethra may be required to demonstrate the presence or absence of an obstructive lesion.