The incidence of presacral tumor, also called retrorectal tumor, is unknown, but retrospective studies suggest that about 1-6 patients with retrorectal tumor are diagnosed each year in large hospitals. It has been shown that retrorectal tumors account for approximately 1 in 40,000 inpatients. The retrorectal space contains embryonic remnants of a variety of tissues, and tumors of this space have a wide variety of morphologic and histologic manifestations. Most lesions are benign, but malignant tumors are not uncommon. Malignant tumors are more common in children than in adults, and solid tumors are more likely to be malignant compared to cystic tumors. Retrorectal tumors are often undetected because of the lack of specific symptoms. Most benign tumors have no obvious symptoms. Occasionally, symptoms of pain or obstruction may be present. Anterior cerebrospinal bulge may have postural headache. Most tumors can be detected by rectal examination. Once a posterior rectal tumor is found on physical examination, imaging examinations such as CT or MRI should be performed to further clarify the diagnosis and are very important for the development of surgical plan. Puncture biopsy is not recommended for tumors that can be resected, but can be considered for patients who cannot be surgically resected or who cannot tolerate surgery. Anatomy The anterior sacral space is located anterior to the anterior sacral fascia, posterior to the rectum, flanked by the intrapelvic fascia (lateral rectal ligament), superiorly by the retroperitoneal retroflexion of the rectum, and inferiorly by the sacrorectal fascia (Waldeyer fascia). This region contains structures that have differentiated from embryonic neuroectoderm, notochord and hindgut, and can also present with a variety of tumors derived from residual embryonic tissue. Thus, the clinical presentation of presacral tumors is diverse. In addition, the complexity of pelvic anatomy often makes pelvic tumor surgery challenging. Pathological types of presacral tumors Dermatomal cysts and epidermoid cysts Dermatomal cysts and epidermoid cysts are benign lesions of ectodermal origin. These lesions are called epidermoid cysts when the cyst wall is lined with squamous epithelial cells and dermal appendages when the cyst wall is lined with squamous epithelial cells and skin appendages. Sometimes the cysts are attached to the skin and form a dimple sign above the posterior anus. Infection occurs in about 30% of cysts. Once infected, cysts are easily misdiagnosed as perianal abscesses, fistulas, and fistulas. Recurrence of cysts after surgical treatment should be considered as a possible congenital cyst. Repetitive cysts of the hindgut Isolated hindgut tissue during embryonic development can lead to thin-walled multihoused cysts lined with columnar epithelium. Hindgut cysts can also present as single-compartment, called posterior rectal cystic malformations. Rectal duplication cysts can also contain various components of the intestinal wall. These cysts are mostly benign, but can also present with malignant changes. Anterior meningocele (anterior meningocele) Anterior meningocele of the cerebrospinal and seminal spine is the result of herniation of the dural sac from a defect anterior to the sacrum. A unilateral sacral defect may appear as a typical scimitar sign on radiographs. Patients often have no specific symptoms, but may have headache. Headaches tend to come on during changes in position, changes in intra-abdominal pressure or during defecation. Puncture drainage is contraindicated because it can lead to meningitis. Chordoma is a malignant tumor originating from the spinal cord and is the most common malignancy of the presacral space. Chordomas are often associated with pain and are more common in men than women. Chordomas can occur anywhere in the spinal cord, but are most common in the sacrococcygeal region. These tumors are slow growing but aggressive and can lead to typical bone destruction. Radical resection is the most effective treatment, but the local recurrence rate is high, with a 10-year survival rate of only 9%-35%. Teratomas Teratomas are true tumors containing tissue of polyembryonic origin and can be cystic or made solid, but are usually mixed cystic and solid masses. As with dermatomes, they are more common in women. Many teratomas contain embryonic cells with malignant potential, and about 10% of teratomas can develop into cancer. Teratomas are more common in children than in adults, and adult teratomas are more likely to be malignant. Teratomas usually contain a variety of tissue components, including respiratory, neurological, and digestive structures. These lesions are often closely associated with the tailbone, and surgery requires that the tumor be removed in its entirety from the tailbone. Residual adrenal tumors Residual tumors of the presacral adrenal glands are rare and are often classified as miscellaneous, although they have the nature of congenital tumors. They are usually treated as ectopic adrenal tumors. Tumors of neurogenic origin often originate from peripheral nerves and account for approximately 10% of presacral tumors, including neurofibromas, neurofibrosarcomas, nerve sheath tumors, ventricular meningiomas, and ganglion cell tumors. Among them, nerve sheath tumors are the most common, and larger nerve sheath tumors can become cystic. Bone tumors Tumors of bone origin account for approximately 10% of presacral tumors and include bone cysts, osteogenic sarcoma, Ewing’s tumor, chondromyxosarcoma, and giant cell tumor of bone. giant cell tumor). Although benign tumors of presacral bone origin can be resected radically, local recurrence may be the biggest problem. Malignant tumors of bone origin tend to progress rapidly and have a poor prognosis. Inflammatory lesions Inflammatory lesions can be solid or cystic and often result from the spread of infection in the perirectal space or retroperitoneal space. Pelvic and perineal infections can also spread to the presacral space. Crohn’s disease and rectal diverticulitis can also present as presacral inflammatory lesions. In addition, some rare inflammatory diseases such as tuberculosis and granulomatous diseases can also present in the presacral space. Other tumors The presacral space also includes a variety of other benign and malignant tumors, including metastatic disease, lymphangioma, leiomyoma, fibrosarcoma, endothelioma, and sclerofibrosarcoma ( The treatment and prognosis depend on the nature of the pathology. Clinical symptoms and preoperative evaluation Symptoms of presacral tumors are related to the location and size of the tumor and often lack typical clinical symptoms. Most benign cystic tumors are asymptomatic and are often detected during routine rectal examination. Infection of the lesion or invasion of bone can produce pain in the lumbosacral region, rectopelvic cavity or lower extremities. Postural headaches or headaches associated with changes in intra-abdominal pressure, such as those occurring during defecation, are often suggestive of anterior cerebrospinal bulge. Large cystic or solid tumors can cause intestinal obstruction, resulting in constipation, difficult defecation, and overflowing fecal incontinence. Anterior sacral tumors can also cause obstruction of the birth canal, resulting in life-threatening obstructed labor. The examination includes rectal examination and imaging. First, a careful rectal examination should be performed. Rectal examination can reveal almost all presacral tumors, and the location, size, and proximal extent of the tumor are important for pre-operative planning of the tumor. Fiberoptic sigmoidoscopy or colonoscopy is important to determine whether there is intestinal involvement. CT is the most widely used diagnostic imaging method, but with advances in technology, pelvic MRI is becoming the most sensitive and specific diagnostic imaging method for presacral tumors. Pre-surgical biopsy Surgical puncture biopsy is rarely needed for presacral lesions. For lesions that can be resected, surgical resection is the best diagnostic and therapeutic tool. For cystic lesions, puncture and aspiration can lead to infection, and cerebrospinal bulge puncture can lead to meningitis. Puncture of malignant tumors may lead to tumor spread and needle tract implant metastasis. If a patient with chordoma has had a puncture biopsy before surgery, the puncture needle tract must be removed at the same time as surgery. Puncture biopsy is primarily used for non-surgically resectable lesions and can guide non-surgical treatment. Puncture biopsy can also be used in cases of severe combined cardiovascular disease that cannot tolerate pelvic surgery. Treatment In principle, surgical resection should be performed for tumors that can tolerate surgery and for lesions that are potentially resectable. The surgical route depends on the location and nature of the lesion. Tumors that do not exceed the level of sacral 4 in the lower pole can be surgically resected by the transabdominal route, which can remove most of the presacral tumors. Tumors that are located lower can be resected via the sacral route. Tumors that can be located in the upper pole of the tumor on rectal examination can usually be removed via the sacral route. If the tumor invades the rectum, en block resection should be performed with the tumor. In case of sacrococcygeal invasion, caudal and or sacral resection is required. For these complex cases, it often requires the collaboration of colorectal surgery, neurosurgery, orthopedics and plastic surgery to ensure successful surgery. Minimally invasive surgery is emerging, and the use of abdominal presacral tumor resection and transanal endoscopic resection has also been reported. Primary presacral malignancies are often resistant to radiotherapy and chemotherapy; therefore, drug therapy and radiotherapy are not effective in treating the majority of presacral tumors. Radiotherapy can sometimes provide pain relief. Pre-sacral metastatic tumors (e.g., rectal cancer metastases) are often effective for radiotherapy. The prognosis of presacral tumors after surgical resection depends on the pathological nature of the tumor and the adequacy of the extent of surgical resection. The outcome of surgery for benign tumors is often satisfactory, but recurrence is possible. Recurrent tumors can be radically resected again. Teratomas tend to accumulate in the tailbone, and caudal resection for teratomas that accumulate in the tailbone may reduce the risk of tumor recurrence. The prognosis of malignant tumors after radical resection varies widely, which is related to the biological characteristics of the tumor. Local recurrence of chordoma is common, and long-term survival rates reported in the literature vary widely, with 5-year survival rates of 43%-75% and 10-year survival rates of 9%-35%. The prognosis for other malignancies tends to be poorer. In conclusion Presacral tumors are rare tumors of diverse histological origin, and although they lack specific clinical manifestations and signs, rectal finger examination can reveal almost all presacral tumors. The vast majority of cases require sexual surgical treatment, and preoperative imaging (especially MRI) is important for surgical planning and design. Avoid puncture biopsy of resectable tumors. Resection of presacral tumors is sometimes difficult and challenging and requires multidisciplinary cooperation.