Abstract: Abstract Objective: The aim of this research is to probe the diagnostic role of ultrasound in pediatric paratubal cyst. Methods: The information of sonographic features, operative findings and histology in cases of paratubal cyst confirmed by post-operative pathology between December 2006 and September 2011 was summarized and analyzed. Ultrasound examinations were performed using LOGIQ7, VULOSON730 and IU22. Results: 35 cases with paratubal cyst were determined by postoperative pathology, which were classified into two groups: ultrasound-negative group (14 cases) and positive group (21cases). Of the ultrasound-positive group, 3 cases were simple cyst, 1 case was cyst complicated with hemorrhage, and 17 cases were complicated with ovary torsion. The diameter of cyst in ultrasound-negative group ranged from 0.3cm to 2cm (median, 0.9cm), whereas it in ultrasound-positive group was from 5.4cm to 11.2cm (median, 7.6cm). Sonograghic findings for paratubal cyst: Cysts located in annex area or rectal fossa, inside which there was an anechoic fluid area. Its shape was round or oval, and its wall was thin and smooth. Normal morphological ovary next to cyst could be found. When secondary torsion occurred the cyst took on spherical shape due to inner hypertonia, and enlargement, hypo echogenicity or hyperechogenicity, and/or hypervascular flow were observed in ipsilateral ovary. Conclusions: Ultrasound examination is useful for preoperative diagnosis and differential diagnosis of paratubal cyst because of its specific sonographic findings.

Key words: paratubal cyst, ultrasonography, hydrosalpinx, ovary torsion, children