Clinical History
A 6-month-old female patient presented with retention of urine.
Imaging Findings
MRI lumbar spine revealed large heterogeneous altered signal intensity lesion in the presacral region. The lesion showed internal fat, calcification, cysts, haemorrhage and soft tissue elements. The lesion was causing compression and displacement of the bladder, uterus and rectum anteriorly without any definite evidence of invasion. The lesion showed minimal intraspinal extension through right S4 neural foramina. There was no evidence of spinal dysraphism in the lumbosacral region.
Discussion
Sacrococcygeal teratoma is the most common presacral germ cell tumour in children and the most common solid tumour in neonates. Approximately 60% of these tumours are benign. Other types of presacral tumour are extremely rare. The majority (60%) of non– central nervous system teratomas originate in the sacrococcygeal region, followed by the ovaries and testes (30%), the mediastinum (5%), and the retroperitoneum (4%) [1, 2].
A prenatal diagnosis of sacrococcygeal teratoma implies a higher risk of preterm delivery caused by secondary polyhydramnios, and development of hydrops and placentomegaly (secondary to high-output cardiac failure associated with arteriovenous shunting). Sacrococcygeal teratomas are associated with other anomalies, including the Currarino triad [1, 3, 4].
The most commonly used classification is the Altman classification. It comprises four groups:
Type I - predominantly extrapelvic masses with a small presacral component
Type II – extrapelvic masses with a significant intrapelvic component
Type III - extrapelvic masses with an abdominopelvic component
Type IV - intrapelvic masses with an abdominal component [1, 2].
Seventy-five percent of children with sacrococcygeal germ cell tumours are female, however, malignant sacrococcygeal teratomas are equally distributed between the sexes [1, 3].
Benign teratomas are predominantly cystic, have attenuation similar to that of fluid on CT images, and may include bone, fat, and calcification. Cystic areas typically have the appearance of fluid on T1-weighted and T2-weighted MR images. Areas of fatty tissue demonstrate high signal intensity on T1-weighted images, whilst calcification and bone are depicted as areas of signal void. The coccyx is always involved, even with benign tumours, and must be resected at the time of surgery. Malignant teratomas have a predominant solid component with haemorrhage and necrosis being common [1].
Serum alpha-1-fetoprotein (AFP) levels are elevated in 50% of malignant teratomas and reflect the presence of a new or growing mass. Measurement of serum AFP levels is routinely used to follow the course of disease and can be used as a guide in determining whether further imaging studies are necessary [1].
Differential Diagnosis List
Sacrococcygeal teratoma (Altman Type IV)
Neuroblastoma
Anterior sacral meningocele
Terminal myelocystocele
Rhabdomyosarcoma
Final Diagnosis
Sacrococcygeal teratoma (Altman Type IV)
