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Sacrococcygeal teratoma (SCT) is a teratoma (a kind of tumor) located at the base of the coccyx (tailbone).

Contents 1 Natural history 2 Treatment 3 Complications 4 References 5 External links

SCT is seen in 1 in every 35,000 live births, and is the most common tumor presenting in the newborn human. The usual presentation is a lump or mass under the skin at the top of the buttocks crease. A small SCT, if it is entirely inside the body, may not present for years. Most SCTs are found in babies and children, but SCTs have been reported in adults^[1] and the increasingly routine use of prenatal ultrasound exams has dramatically increased the number of SCTs presenting in fetuses. Like all other teratomas, an SCT can grow very large. Due to its location, however, an SCT can grow larger than the fetus yet the fetus may survive.

The preferred first treatment for SCT is complete surgical removal (ie, complete resection). The preferred approach to a small SCT is through the perineum; a large SCT may require an additional approach through the abdomen. Resection should include the coccyx and may also include portions of the sacrum. The surgery should include reattachment of the small muscles and ligaments formerly attached to the coccyx, in effect reconstructing the posterior perineum.

SCTs are classified morphologically according to how much of them is outside or inside the body:

• Altman Type I — entirely external, sometimes attached to the body only by a narrow stalk
• Altman Type II
• Altman Type III
• Altman Type IV — entirely internal; this is a presacral teratoma

The Altman Type has a significant influence on management, surgical approach, and complications of SCT. Serial ultrasound and MRI monitoring of SCTs in fetuses in utero has demonstrated that the Altman Type can change over time.

Regardless of location in the body, teratomas are classified according to a cancer staging system. This indicates whether chemotherapy or radiation therapy may be needed.

Complications of the mass effect of a teratoma in general are addressed on the teratoma page. Complications of the mass effect of a large SCT may include hip dysplasia, bowel obstruction, urinary obstruction, hydronephrosis and hydrops. In the fetus, severe hydronephrosis may contribute to inadequate lung development. Also in the fetus and newborn, the anus may be imperforate.

Complications of surgery may include neurogenic bladder and other problems resulting from accidental damage to or sacrifice of nerves within the pelvis. In adults, one infrequent complication of removal of the coccyx (coccygectomy) is perineal hernia, but this appears not to be a concern when the patient is an infant.

Complications of not removing the coccyx include recurrence of the teratoma and metastatic cancer.^[2]

1. ^ Killen DA, Jackson LM (1964) Sacrococcygeal teratoma in the adult" Archives of Surgery 88(3):425-433.
2. ^ Lack EE et al (1993) "Late occurrence of malignancy following resection of a histologically mature sacrococcygeal teratoma — report of a case and literature review" Archives of Pathology & Laboratory Medicine 117(7):724-728. A 40 year old man has widely metastatic adenocarcinoma arising from the residual coccyx remaining after surgical removal of a benign SCT at age 2 months.

• medium size benign SCT diagnosed via ultrasound, with complications, delivered preterm via cesarean section
• large benign SCT diagnosed via routine prenatal ultrasound, delivered near term via cesarean section
• large benign SCT delivered full term vaginally, initially misdiagnosed as spina bifida, correctly diagnosed at age 5 weeks, in 1962