DISCUSSION
The incidence of PBS is estimated to occur in 1:40,000 live births with more than 95% affecting males, its characterized by triad of deficient abdominal wall muscles, bilateral cryptorchidism and abnormalities of urinary tract such as hydronephrosis, hydroureter/mega ureter and persistent urachus, megacystis with megalourethra (1,2). Literature on the cause and embryogenetic factors of PPBS and PBS is controversial, majority postulates that its due to three possible factors occurring during embryogenesis; like severe bladder outlet obstruction, dysgenesis of yolk sac and possibly due to abdominal muscle deficiency secondary to migrational defect of mesoblast during early 1sttrimester of pregnancy (1,2,8). Prognosis of infants with PBS is poor with IUFD, still births and early infant death being common (5,9,10). Physical finding that support the diagnosis of PBS include a penile abnormalities (megalourethra, urethral atresia), patent urachus and musculoskeletal abnormalities (1,2,4,7). The clinical severity of PBS is widely variable, depending upon the timing, location, and degree of the embryologic insult. Some patients have severe manifestations which lead to still birth or infant death while others demonstrate very mild disease which requires little or no therapy (6,9,11).
The terminology of “Pseudo Prune Belly Syndrome (PPBS) has been Suggested to define those who do not complete the triad of PBS (1,4,12). PPBS is a term used to describe infants who do not fulfill the criteria of classic PBS, consisting of abdominal wall muscle deficiency or hypoplasia, urologic abnormality, and cryptorchidism, terms such as “incomplete prune belly syndrome” or “partial prune belly Syndrome” have been used to describe children cryptorchidism, mild urinary tract abnormalities and mild or unilateral deficiency of abdominal musculature: deficient prune like abdominal wall and normal genitourinary system. Numerous report was described in children with only mild diastasis of the rectus abdominis musculature or abdominal wall deficiency with normal urinary tract imaging that the syndrome goes unrecognized (8,11). The term “pseudo prune” or partial prune can then be applied to a patient once the urologic hallmarks of PBS are recognized on urologic imaging that is done for indications other than PBS (1). PPBS includes patients who exhibit: (1) unilateral abdominal wall muscular deficiency, cryptorchidism, and urinary tract anomalies; (2) abdominal wall muscular deficiency alone; (3) abdominal muscular deficiency with either urinary tract anomalies or cryptorchidism; or (4) characteristic urinary tract anomalies and cryptorchidism but normal abdominal wall musculature (3,4). Sometimes, abdominal wall muscular hypoplasia is subtle or limited to diastasis of the rectus abdominis muscles (4).
Although the incomplete expression of the classic triad illustrated by our case is stated to occur at the same incidence as the complete triad, PPBS has not been emphasized in the literature (3,4). PPBS is generally characterized by partial or unilateral abdominal wall deficiency or unilateral undescended testis that can usually be palpable in the inguinal canal (4,11). Our patient is case of PPBS, which can be considered as a possible variant of the syndrome.