Sacrococcygeal teratoma
Updates to Article Attributes
Sacro-coccygealSacrococcygeal teratoma (SCT) refers to ateratoma arising in the sacro-coccygealsacrococcygeal region. The coccyx is almost always involved 6.
Demographics and clinical presentationEpidemiology
It is the commonest congenital tumour in the fetus 11 11 and neonate 3. The incidence is estimated at ~1:35000-40000. There is recognised female predilection with aan M:F ratio of 1:4. Sacrococcygeal region is the commonest location for non CNS-CNS teratomas.
Clinical presentation
Presentation varies depending on if the tumour has an intrapelvic location or has an extra-fetal extension (see further classification bellow). Intrapelvic tumours can manifest after birth with genitourinary and gastrointestinal symptoms given the compression of those structurers.
Pathology
They are thought to arise from totipotent cells from the node of Hensen 1,3 at the anterior aspect of the coccyx by about the 2nd to 3rd weeks of gestation. There are most often mixed solid/cystic, although purely cystic types can occur in ~15% of cases.
The tumour is composed of the all three germ cells (i.e. ectoderm, mesoderm and endoderm)
Genetics
- most cases tend to be sporadic 12
Associations
Markers
Can have elevated levels of:
- alpha
feto proteinfetoprotein (AFP) - beta HCG
Classification
A pathology-based classification is as:
- benign (mature): much more common, comprising ≈60-70%
- malignant (immature)
A location based classification system according to the American Academy of Pediatric Surgery Section Survey is:
- type I: developing only outside the fetus (can have small pre-sacral component); accounts for the majority of cases, 47% 12
- type II: extra-fetal with intra-pelvic pre-sacral extension
-
type III: extra-fetal with
abdomino-pelvicabdominopelvic extension -
type IV: tumour developing
completelyentirely in the fetal pelvis
Radiographic features
Plain filmradiograph
- may show a large mass projecting from the lower pelvic region or within the abdominopelvic cavity
- may show calcification
CT
Not part of a routine investigation. Identifies bone, fat and cystic components. Calcification may again be seen.
Ultrasound
Mature types tend to be more cystic which show as anechoic components. Solid types (which are much rarer) often show an echogenic mass within the pelvis.
The correlation between sonographic appearances and malignant components are thought to be poor 7.
Colour Doppler interrogation in some tumours may show marked hypervascularity with arterio-venous (AV) shunting.
MRI
Superior to ultrasound especially in the assessment of the following areas 2:
- colonic displacement
- ureteric dilatation
- associated hip dislocation
- intraspinal extension
- vaginal dilatation
- metastatic assessment in malignant lesions
Signal characteristics can significantly vary depending on the constituent of the teratoma1.
- T1: fat components appear high signal, calcific/bony components low signal
- T2: fluid (cystic) components appear high signal, calcific bony components low signal
-
T2* GRE: magnetic susceptibility
artifactartefact because of calcifications - T1 C+ (Gd): enhancing solid components
Treatment and prognosis
An SCT can be benign or malignant depending on whether mature or immature. The majority, however, tend to be benign (~80% 11). Those presenting in older infants tend to have a higher malignant potential which those presenting in utero have a poor prognosis due to complications. Malignant change may be also commoner in males. Treatment is with surgical excision inclusive of coccygectomy with additional chemotherapy for malignant tumours 5.
Complications
- high output cardiac failure from AV shunting: which in turn can cause hydrops fetalis
- ureteric obstruction
- gastro-intestinal tract obstruction
- compression of underlying nerves: giving urinary/faecal incontinence
- anaemia
- dystocia
- tumour rupture
Treatment and prognosis
An SCT can be benign or malignant depending on whether mature or immature. The majority however tend to be benign (~80% 11). Those presenting in older infants tend to have a higher malignant potential which those presenting in utero have poor prognosis due to complications. Malignant change may be also commoner in males. Treatment is with surgical excision inclusive of coccygectomy with additional chemotherapy for malignant tumours 5.
Differential diagnosis
General imaging differential considerations include:
- sacral chordoma
- terminal myelocystocoele: for cystic types on ultrasound 9
- sacral meningocoele
For type IV lesions also consider:
- low
lying-lying neuroblastoma - low
lying-lying rhabdomyosarcoma - small round blue cell tumour in the sacral region
-
enteric
(tail gut(tailgut) cyst: for a purely cystic SCT
-<p><strong>Sacro-coccygeal teratoma (SCT)</strong> refers to a <a href="/articles/teratoma">teratoma</a> arising in the sacro-coccygeal region. The coccyx is almost always involved <sup>6</sup>.</p><h4>Demographics and clinical presentation</h4><p>It is the commonest congenital tumour in the fetus<sup> 11</sup> and neonate <sup>3</sup>. The incidence is estimated at ~1:35000-40000. There is recognised female predilection with a M:F ratio of 1:4. Sacrococcygeal region is the commonest location for non CNS teratomas.</p><h4>Pathology</h4><p>They are thought to arise from totipotent cells from the <a href="/articles/node-of-hensen">node of Hensen</a> <sup>1,3 </sup>at the anterior aspect of the coccyx by about the 2<sup>nd</sup> to 3<sup>rd</sup> weeks of gestation. There are most often mixed solid/cystic, although purely cystic types can occur in ~15% of cases.</p><p>The tumour is composed of the all three germ cells (i.e. ectoderm, mesoderm and endoderm)</p><h5>Genetics</h5><ul><li>most cases tend to be sporadic <sup>12</sup>- +<p><strong>Sacrococcygeal teratoma (SCT)</strong> refers to a <a href="/articles/teratoma">teratoma</a> arising in the sacrococcygeal region. The coccyx is almost always involved <sup>6</sup>.</p><h4>Epidemiology</h4><p>It is the commonest congenital tumour in the fetus<sup> 11</sup> and neonate <sup>3</sup>. The incidence is estimated at ~1:35000-40000. There is recognised female predilection with an M:F ratio of 1:4. Sacrococcygeal region is the commonest location for non-CNS teratomas.</p><h4>Clinical presentation</h4><p>Presentation varies depending on if the tumour has an intrapelvic location or has an extra-fetal extension (see further classification bellow). Intrapelvic tumours can manifest after birth with genitourinary and gastrointestinal symptoms given the compression of those structurers. </p><p><strong style="font-size:1.5em; font-weight:bold">Pathology</strong></p><p>They are thought to arise from totipotent cells from the <a href="/articles/node-of-hensen">node of Hensen</a> <sup>1,3 </sup>at the anterior aspect of the coccyx by about the 2<sup>nd</sup> to 3<sup>rd</sup> weeks of gestation. There are most often mixed solid/cystic, although purely cystic types can occur in ~15% of cases.</p><p>The tumour is composed of the all three germ cells (i.e. ectoderm, mesoderm and endoderm)</p><h5>Genetics</h5><ul><li>most cases tend to be sporadic <sup>12</sup>
-<li>alpha feto protein (AFP)</li>- +<li>alpha fetoprotein (AFP)</li>
-<strong>type I:</strong> developing only outside the fetus (can have small pre-sacral component) ; accounts for the majority of cases, 47% <sup>12</sup>- +<strong>type I:</strong> developing only outside the fetus (can have small pre-sacral component); accounts for the majority of cases, 47% <sup>12</sup>
-<strong>type III:</strong> extra-fetal with abdomino-pelvic extension</li>- +<strong>type III:</strong> extra-fetal with abdominopelvic extension</li>
-<strong>type IV:</strong> tumour developing completely in the fetal pelvis</li>-</ul><h4>Radiographic features</h4><h5>Plain film</h5><ul>- +<strong>type IV:</strong> tumour developing entirely in the fetal pelvis</li>
- +</ul><h4>Radiographic features</h4><h5>Plain radiograph</h5><ul>
-</ul><h5>CT</h5><p>Not part of routine investigation. Identifies bone, fat and cystic components. Calcification may again be seen.</p><h5>Ultrasound</h5><p>Mature types tend to be more cystic which show as anechoic components. Solid types (which are much rarer) often show an echogenic mass within the pelvis.</p><p>The correlation between sonographic appearances and malignant components are thought to be poor <sup>7</sup>.</p><p>Colour Doppler interrogation in some tumours may show marked hypervascularity with arterio-venous (AV) shunting.</p><h5>MRI</h5><p>Superior to ultrasound especially in assessment of the following areas <sup>2</sup>:</p><ul>- +</ul><h5>CT</h5><p>Not part of a routine investigation. Identifies bone, fat and cystic components. Calcification may again be seen.</p><h5>Ultrasound</h5><p>Mature types tend to be more cystic which show as anechoic components. Solid types (which are much rarer) often show an echogenic mass within the pelvis.</p><p>The correlation between sonographic appearances and malignant components are thought to be poor <sup>7</sup>.</p><p>Colour Doppler interrogation in some tumours may show marked hypervascularity with arterio-venous (AV) shunting.</p><h5>MRI</h5><p>Superior to ultrasound especially in the assessment of the following areas <sup>2</sup>:</p><ul>
-</ul><p>Signal characteristics can significantly vary depending on the constituent of the teratoma <sup>1</sup>.</p><ul>- +</ul><p>Signal characteristics can significantly vary depending on the constituent of the teratoma <sup>1</sup>.</p><ul>
-<strong>T2* GRE:</strong> magnetic susceptibility artifact because of calcifications</li>- +<strong>T2* GRE:</strong> magnetic susceptibility artefact because of calcifications</li>
-</ul><h4>Complications</h4><ul>- +</ul><h4>Treatment and prognosis</h4><p>An SCT can be benign or malignant depending on whether mature or immature. The majority, however, tend to be benign (~80% <sup>11</sup>). Those presenting in older infants tend to have a higher malignant potential which those presenting in utero have a poor prognosis due to complications. Malignant change may be also commoner in males. Treatment is with surgical excision inclusive of coccygectomy with additional chemotherapy for malignant tumours <sup>5</sup>.</p><h5>Complications</h5><ul>
-</ul><h4>Treatment and prognosis</h4><p>An SCT can be benign or malignant depending on whether mature or immature. The majority however tend to be benign (~80% <sup>11</sup>). Those presenting in older infants tend to have a higher malignant potential which those presenting in utero have poor prognosis due to complications. Malignant change may be also commoner in males. Treatment is with surgical excision inclusive of coccygectomy with additional chemotherapy for malignant tumours <sup>5</sup>.</p><h4>Differential diagnosis</h4><p>General imaging differential considerations include:</p><ul>- +</ul><h4>Differential diagnosis</h4><p>General imaging differential considerations include:</p><ul>
-<li>low lying <a href="/articles/neuroblastoma">neuroblastoma</a>- +<li>low-lying <a href="/articles/neuroblastoma">neuroblastoma</a>
-<li>low lying <a href="/articles/rhabdomyosarcoma">rhabdomyosarcoma</a>- +<li>low-lying <a href="/articles/rhabdomyosarcoma">rhabdomyosarcoma</a>
-<a href="/articles/small-round-blue-cell-tumours">small round blue cell tumour</a> in sacral region</li>- +<a href="/articles/small-round-blue-cell-tumours">small round blue cell tumour</a> in the sacral region</li>
-<a href="/articles/enteric-tail-gut-cyst">enteric (tail gut) cyst</a>: for a purely cystic SCT</li>- +<a href="/articles/enteric-tail-gut-cyst">enteric (tailgut) cyst</a>: for a purely cystic SCT</li>