Torsion of the gonad in the pediatric population: spectrum of histologic findings with focus on aspects specific to neonates and infants.

Histopathologic findings of gonadal torsion in neonates and infants (GTNI) are poorly defined in the literature. We describe herein the histopathologic spectrum of GT with emphasis on the pediatric population and on features specific for NI (≤1 year of age). Twenty-four cases of GTNI (6 females/18 males), 33 cases of GT in an older pediatric population (OPP) (19 females/14 males), and 43 cases of GT in adults (35 females/8 males) were found in our pathology files between 2003 and 2011. Our findings disclosed 2 categories of GT: 1) the group of NI, and 2) that of OPP and adults who share a similar presentation as acute hemorrhagic necrosis of the gonad. Although findings in NI were rather uniform, a few differences were demonstrated between the 2 genders. All GTNI revealed calcifications, fibrosis, siderophages, and extensive necrosis. However, prominent necrotizing palisaded granulomatas were seen in most (4 of 6) cases of ovarian torsion but not in the testicular counterpart. Furthermore, complete gonad regression was encountered exclusively in neonatal testicular torsion cases. In conclusion, 1) pathologic findings in GT are distinctly different between NI and OPP, the latter being more comparable to adults, presenting with acute hemorrhagic necrosis; 2) the distinctive findings in GTNI of both genders include calcifications, siderophages, and fibrosis, in addition to background necrosis; 3) of particular note, complete gonadal regression is seen only in the testis in GTNI; and 4) necrotizing palisaded granulomatas are unique to the ovarian subgroup and are often extensive, obscuring the nature of the process.