Sacrococcygeal teratoma overview
Mirdula Sharma, MBBS 

# Overview
Sacrococcygel teratoma was first described by Stanley in 1842. In 1863, first successful surgery was performed on Sacrococcygeal teratoma by Dr. W. Blizard. Between 1950s and 1960s, germ cell theory of the origin of Sacrococcygeal teratoma was introduced. Sacrococcygeal teratoma is one of the most common congenital tumors. The incidence of Sacrococcygeal teratoma is estimated to be 1 in 35,000 births.
Sacrococcygeal teratoma is classified into four different categories according to American Academy of Pediatrics Surgery classification based upon the anatomical location of the tumor. Subtypes of sacrococcygeal teratoma have different staging systems based on the size and growth of the tumor, lymph node involvement, and the presence of metastasis. Sacrococcygeal teratoma originates from the pluripotent cells in primitive knot or Hensen's node, which is the primary organizer of embryonic development, located on the anterior surface of the sacrum or coccyx by 2rd or 3rd gestational week. Development of Sacrococcygeal teratoma is associated with gain of chromosomes 1q32-qter regions and losses of the 6q24-qter and 18q21-qter regions. The pathophysiology of sacrococcygeal teratoma depends on the histological subtype. Development of sacrococcygeal teratoma is associated with gain of chromosomes 1q32-qter regions and losses of the 6q24-qter and 18q21-qter regions. Sacrococcygeal teratoma must be differentiated from endodermal sinus tumor, ependymoma, fibromatosis, ganglioneuroma, giant cell tumor of the sacrum, leiomyoma, meningomyelocele, ovarian teratoma, neuroblastoma, retrorectal hamartoma, intracanalicular epidermoid tumor, rhabdomyosarcoma, paraganglioma, dermal sinus stalk ascending towards the conus modulars, and hydromelia. According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for sacrococcygela teratoma. The hallmark of sacrococcygeal teratoma is a protruding mass at the sacrococcygeal region. It is important to obtain the history about the onset, and the progression of the symptoms. Most common symptoms of sacrococcygeal teratoma are due to compression caused by the large tumor mass. Patient with sacrococcygeal teratoma usually are generally well-appearanceing. Physical examination of patients with sacrococcygeal teratoma is usually remarkable for a protruding pre sacral mass. Alpha-Fetoprotein and beta-hCG should be evaluated in patients with sacrococcygeal teratoma to determine the presence of malignant component of the tumor. On x-ray, sacrococcygeal teratoma is characterized by a large mass projecting from the lower pelvic region or within the abdominopelvic cavity. CT scan is not part of the routine investigation of sacrococcygeal teratoma. On CT scan, sacrococcygeal teratoma is characterized by bone, fat, and cystic components. Ultrasound is used to diagnose Sacrococcygeal teratoma in second trimester. Mature sacrococcygeal teratomas tend to be cystic, showing anechoic component. Immature sacrococcygeal teratomas are much rare and solid type, showing echogenic mass within the pelvis. Echocardiography identifies high output cardiac state preceding hydrops fetalis. Colour Doppler studies in sacrococcygeal teratoma may show marked hypervascularity with arterio-venous (AV) shunting. There is no medical treatment for sacrococcygeal teratoma; the mainstay of therapy is surgical. Perinatal surgical intervention is used to decrease cardiovascular complications caused by the large sacrococcygeal teratoma. Early complete resection is the mainstay of management of benign tumor. Complete surgical excision in malignant sacrococcygeal teratoma is followed by platinum based chemotherapy. Depending on the extent of the tumor at the time of diagnosis, the prognosis may vary. Most of the sacrococcygeal teratomas are benign in nature and prognosis is generally regarded as good after resection. The sacrococcygeal teratoma with cystic morphology is associated with the most favorable prognosis.

# Historical Perspective
Sacrococcygel teratoma was first described by Stanley in 1842. In 1863, first successful surgery was performed on Sacrococcygeal teratoma by Dr. W. Blizard. Between 1950s and 1960s, germ cell theory of the origin of Sacrococcygeal teratoma was introduced.

# Classification
Sacrococcygeal teratoma is classified into four different categories according to American Academy of Pediatrics Surgery classification based upon the anatomical location of the tumor. Subtypes of sacrococcygeal teratoma have different staging systems based on the size and growth of the tumor, lymph node involvement, and the presence of metastasis.

# Pathophysiology
Sacrococcygeal teratoma originates from the pluripotent cells in primitive knot or Hensen's node, which is the primary organizer of embryonic development, located on the anterior surface of the sacrum or coccyx by 2rd or 3rd gestational week. Development of Sacrococcygeal teratoma is associated with gain of chromosomes 1q32-qter regions and losses of the 6q24-qter and 18q21-qter regions. The pathophysiology of sacrococcygeal teratoma depends on the histological subtype.

# Causes
Development of sacrococcygeal teratoma is associated with gain of chromosomes 1q32-qter regions and losses of the 6q24-qter and 18q21-qter regions.

# Differential Diagnosis
Sacrococcygeal teratoma must be differentiated from endodermal sinus tumor, ependymoma, fibromatosis, ganglioneuroma, giant cell tumor of the sacrum, leiomyoma, meningomyelocele, ovarian teratoma, neuroblastoma, retrorectal hamartoma, intracanalicular epidermoid tumor, rhabdomyosarcoma, paraganglioma, dermal sinus stalk ascending towards the conus modulars, and hydromelia.

# Epidemiology & Demographics
Sacrococcygeal teratoma is one of the most common congenital tumors. The incidence of Sacrococcygeal teratoma is estimated to be 1 in 35,000 births.

# Risk Factors
There are no established risk factors for sacrococcygeal teratoma.

# Screening
According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for sacrococcygela teratoma.

# Natural History, Complications, and Prognosis
Depending on the extent of the tumor at the time of diagnosis, the prognosis may vary. Most of the sacrococcygeal teratomas are benign in nature and prognosis is generally regarded as good after resection. The sacrococcygeal teratoma with cystic morphology is associated with the most favorable prognosis.

# History and Symptoms
The hallmark of sacrococcygeal teratoma is a protruding mass at the sacrococcygeal region. It is important to obtain the history about the onset, and the progression of the symptoms. Most common symptoms of sacrococcygeal teratoma are due to compression caused by the large tumor mass.

# Physical Examination
Patient with sacrococcygeal teratoma usually are generally well-appearanceing. Physical examination of patients with sacrococcygeal teratoma is usually remarkable for a protruding pre sacral mass.

# Laboratory tests
Alpha-Fetoprotein and beta-hCG should be evaluated in patients with sacrococcygeal teratoma to determine the presence of malignant component of the tumor.

# Pelvic X-Ray Findings in Sacrococcygeal Teratoma
On x-ray, sacrococcygeal teratoma is characterized by a large mass projecting from the lower pelvic region or within the abdominopelvic cavity.

# CT Findings in Sacrococcygeal Teratoma
CT scan is not part of the routine investigation of sacrococcygeal teratoma. On CT scan, sacrococcygeal teratoma is characterized by bone, fat, and cystic components.

# Ultrasound Findings in Sacrococcygeal Teratoma
Ultrasound is used to diagnose Sacrococcygeal teratoma in second trimester. Mature sacrococcygeal teratomas tend to be cystic, showing anechoic component. Immature sacrococcygeal teratomas are much rare and solid type, showing echogenic mass within the pelvis. Echocardiography identifies high output cardiac state preceding hydrops fetalis.

# Other Imaging Findings
Colour Doppler studies in sacrococcygeal teratoma may show marked hypervascularity with arterio-venous (AV) shunting.

# Medical Therapy
There is no medical treatment for sacrococcygeal teratoma; the mainstay of therapy is surgical.

# Surgery
Perinatal surgical intervention is used to decrease cardiovascular complications caused by the large sacrococcygeal teratoma. Early complete resection is the mainstay of management of benign tumor. Complete surgical excision in malignant sacrococcygeal teratoma is followed by platinum based chemotherapy.