# Fetal Megacystis: A New Morphologic, Immunohistochemistryistological and Embiogenetic Approach
## 2 Materials and Methods  
Two fetuses with urinary tract malformations were examined in the Pathologic Anatomy Section of the G.F. Ingrassia Department, University of Catania, Italy. The study was conducted in accordance with with the Declaration of Helsinki, and the protocol was approved by the Ethics Committee of Catania 1 (48102 of 7 November, according to national legislation about osservational studies, 20 March 2008, AIFA).  
Case 1: 19 th week termination of pregnancy (TOP); male, 330 gr; total length 24 cm; crown\(-\)rump (CR) length 15.3 cm; medial length of foot 3 cm; cranial circumference 15.5 cm; thoracic circumference 13 cm; abdominal circumference 11 cm. Ruby red skin; perforated orifices. Umbilical cord stump 10 x 0.7 cm; edema of penis. The anatomic relationship of thoracic organs was normal: heart in situs solitus with atrium\(-\)ventricular and ventricular\(-\)vascular concordance and lung development coherent with gestational age. Examination of the abdominal cavity showed: megacystis (25 mm sagittal diameter) with thickened wall (6 mm), megaureter with stenosis of ureteral orifices in the bladder, and bilateral hydronephrotic kidneys (both 18 mm maximum diameter).  
Ecographic diagnosis: urinary obstruction syndrome due to posterior urethral valve (PUV). The US (ultrasonographic) examination showed a megacystis with a maximum diameter of 44 mm and mild hydroureteronephrosis with bright hyperechogenic kidneys. The bladder had the so-called \"key hole sign\", suggesting a possible PUV. Fetal biometry and amniotic fluid were appropriate for gestational age (GA). No other major abnormalities were detected (Figure 1).  
Case 2: 15 th week TOP; XYX karyotype; 40 gr; total length 11 cm; crown\(-\)rump (CR) length 8.5 cm; medial length of foot 1.5 cm; cranial circumference 7 cm; thoracic circumference 6 cm; abdominal circumference 7 cm. Ruby red skin; imperforated orifices. Turricephal and anencephal skull, prognathism, prominent ocular bulbs and low implant of the ears. The abdominal wall was flacid due to the incomplete development of the diaphragm and ribs. The abdominal organs were herniated in the thoracic cavity and in the neck across the skin. Megacystis (65 mm sagittal diameter) with a thinned wall (2 mm) occupied the abdominal and thoracic cavities; both kidneys and surrenal glands were underdeveloped (both with a maximum diameter of 10 mm).  
Ecographic diagnosis: Prune-Belly syndrome, PBS. The ultrasonographic (US) examination was very difficult due to maternal BMI \(>\) 35 and the anhydramios\(-\)absence of amniotic fluid. The fetus showed a megacystis with a maximum diameter of 38 mm. The whole fetal body had a very uncommon posture and it was impossible to assess other fetal structures because of the anhydramios (Figure 2).  
Figure 1: Case 1, US (ultrasonographic). (**A**) Sagittal view of the entire fetus with megacystis. (**B**) Coronal view of the bladder with the keyhole sign. (**C**) Coronal view of the hyperechogenic kidneys. Courtesy of Dr. [PERSON].  
The organs of both fetuses were carefully dissected, separated from each other, fixed in 10% buffered formalin and processed until paraffin embedding. 5 um sections were stained with hematoxylin-eosin (EE). Additional immunohistochemical stainings with smooth muscular actin (SMA, Clone 1A4, Dako, Glostrup, Denmark, Dil: 1:100), S100 protein (polyclonal, Dako, Glostrup, Denmark, Dil. 1:100) and WT1c (clone WT 6F-H2, Dako, Glostrup, Denmark, prediluted) were performed on bladder and bowel slides. Bladder and bowel samples from a fetus of XXI gestational age were considered as a normal control.