Mature sacrococcygeal teratoma

Case contributed by Dr Michael P Hartung


African newborn with very large pelvic mass.

Patient Data

Age: 1 days
Gender: Female

Severe right hydronephrosis. Moderate left hydronephrosis.

Massive cystic mass which occupies a large portion of the abdomen, extends along the presacral space, and caudally with a large extrapelvic component conforming to the gluteal soft tissues. The overall shape of the mass resembles a "dumbbell", with the waist of the dumbbell in the presacral region (American Association of pediatric surgery section classification type II). No enhancing soft tissue component or calcifications are identified. The mass displaces the abdominal organs and large and small bowel without definite bowel obstruction. There is a presumed rectal tube present. 

Example measurements of the mass are as follows:

Intra-abdominal component maximum axial measurement: 5.4 x 7.2 cm

Extra-abdominal/gluteal component maximum axial measurement 6.6 x 8.5 cm.

Total craniocaudal extent of the mass: 15 cm.


1. Very large dumbbell shaped cystic mass with large intra-abdominal and extra-abdominal components. Imaging features are characteristic of a benign mature sacrococcygeal teratoma. No enhancing or solid soft tissue component of the mass is identified. The mass is likely responsible for obstruction of the kidneys, and results in severe hydronephrosis of the right kidney and moderate hydronephrosis of the left kidney. There is mass effect on the intra-abdominal organs and bowel from the intra-abdominal component. 

Case Discussion

The shape of the mass with cystic composition, age of the patient, and lack of soft tissue component make the diagnosis of mature benign sacrococcygeal teratoma basically certain. 

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