Malignant transformation of sacrococcygeal teratoma versus presacral teratoma in Currarino syndrome: Results of ‘The SCT-study’

Background: The risk of malignant transformation and recurrence of Sacrococcygeal Teratoma (SCT) is relatively high, while it is possibly lower in cases associated with Currarino Syndrome (CS). However, the existing literature gives contradictory results. We aimed to examine the risk of malignant transformation in a large cohort of SCT and CS patients. Methods: In a global retrospective cohort study, data of consecutive SCT patients and CS patients with presacral teratoma was obtained from 132 institutes in 62 countries. Malignant transformation, defined as malignancy at initial resection, malignant recurrence, or death due to malignancy was analysed for SCT and CS patients. The rate of malignant transformation was analysed with log-rank test and compared between groups. Results: Of 3612 patients with presacral teratoma, 3388 entered analysis; 3183 SCT and 205 CS patients. The percentage of patients with malignant transformation at initial resection was higher in the SCT versus the CS group, 10·3 % and 31·9 % after one and two years, versus 4·2 % in CS patients after two years, respectively (p < 0.001). Histology in recurrent teratoma was malignant in 35·4 % (n = 114) of SCT patients and 5·9 % (n = 1) of CS patients (p = 0.005). Survival in both groups was equivalent at 94·9 % in SCT patients versus 96·9 % in CS patients (p = 0·343) Conclusion: The SCT-study shows that malignancy is more often present in SCT than in CS patients with an increasing risk of malignant transformation with age compared to CS patients in whom malignancy is rare. Recurrence after resection was more often malignant in the SCT group. Level of evidence: level III.