Megacystis-microcolon-intestinal hypoperistalsis syndrome: in utero sonographic appearance and the contribution of vesicocentesis in antenatal diagnosis.

Objective. The purpose of this report is to describe the in utero sonographic appearance of megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) and examine the role of vesicocentesis. Methods. Two cases of the sonographic appearance of MMIHS were reviewed. We performed vesicocentesis in 2 fetuses with MMIHS and performed vesicoamniotic shunting in 1 of them. The sonographic findings after these procedures were compared with those before puncture. Results. In both cases, ultrasound examination showed a massively enlarged fetal bladder and bilateral hydroureteronephrosis with a normal amount of amniotic fluid. Fetal urinary sodium and chloride concentrations were within normal limits in both cases; this suggested normal fetal renal function. Generally, it is difficult to detect the dilated fetal bowel in MMIHS, probably because of the disturbance caused by a large bladder. In our cases, however, the ultrasound examination clearly showed fetal bowel dilatation after these procedures; this made the antenatal diagnosis of MMIHS more definite. Conclusions. The sonographic features after vesicocentesis may be helpful in confirming the antenatal diagnosis of MMIHS. Key words: fetal urinalysis; megacystis-microcolon-intestinal hypoperistalsis syndrome; sonographic appearance; vesicocentesis.