Diagnostic accuracy of imaging approaches for early tumor detection in children with Li-Fraumeni syndrome.

BACKGROUND: The Toronto protocol for cancer surveillance in children with Li-Fraumeni syndrome has been adopted worldwide. OBJECTIVE: To assess the diagnostic accuracy of the imaging used in this protocol. MATERIALS AND METHODS: We conducted a blinded retrospective review of imaging modalities in 31 pediatric patients. We compared imaging findings with the reference standards, which consisted of (1) histopathological diagnosis, (2) corresponding dedicated imaging or subsequent surveillance imaging or (3) clinical outcomes. We individually analyzed each modality's diagnostic performance for cancer detection and assessed it on a per-study basis for chest and abdominal regional whole-body MRI (n=115 each), brain MRI (n=101) and abdominal/pelvic US (n=292), and on a per-lesion basis for skeleton/soft tissues on whole-body MRI (n=140). RESULTS: Of 763 studies/lesions, approximately 80% had reference standards that identified 4 (0.7%) true-positive, 523 (85.3%) true-negative, 5 (0.8%) false-positive, 3 (0.5%) false-negative and 78 (12.7%) indeterminate results. There were 3 true-positives on whole-body MRI and 1 true-positive on brain MRI as well as 3 false-negatives on whole-body MRI. Sensitivities and specificities of tumor diagnosis using a worst-case scenario analysis were, respectively, 40.0% (95% confidence interval [CI]: 7.3%, 83.0%) and 38.2% (95% CI: 29.2%, 48.0%) for skeleton/soft tissues on whole-body MRI; sensitivity non-available and 97.8% (95% CI: 91.4%, 99.6%) for chest regional whole-body MRI; 100.0% (95% CI: 5.5%, 100.0%) and 96.8% (95% CI: 90.2%, 99.2%) for abdominal regional whole-body MRI; sensitivity non-available and 98.3% (95% CI: 95.3, 99.4) for abdominal/pelvic US; and 50.0% (95% CI: 2.7%, 97.3%) and 93.8% (95% CI: 85.6%, 97.7%) for brain MRI. CONCLUSION: Considerations for optimizing imaging protocol, defining criteria for abnormalities, developing a structured reporting system, and practicing consensus double-reading may enhance the diagnostic accuracy for tumor surveillance.

An Unusual Case of Live Caesarean Scar Ectopic Pregnancy: A Common Entity in an Uncommon Location.

BACKGROUND: Scar pregnancy is an extremely rare type of ectopic pregnancy, where there is implantation of the gestational sac onto the anterior wall of the uterus at the site of previous LSCS scar in a multipara female. Due to a poor vascular supply to the lower uterine segment, caesarean scars may heal improperly predisposing it to be a site of improper implantation of the gestational sac. RESULTS: The characteristic features are empty uterus and cervix, gestational sac in the anterior part of lower uterine segment with a history of painless vaginal bleeding. It carries a high risk of morbidity related to uterine rupture and extensive haemorrhage. CONCLUSIONS: In case of a previous LSCS delivery in a female with a viable gestational sac in the lower uterine segment and elevated B-Hcg levels, the possibility of scar ectopic pregnancy should be considered. KCl or methotrexate can be injected directly into the foetal pole under transvaginal ultrasound guidance in order to stop the cardiac activity in the foetus. The knowledge of the specific ultrasound features of uncommon locations of ectopic pregnancies such as an ectopic scar is crucial for a correct diagnosis and early management in order to prevent complications.