|Ahead of print publication
Management of tailgut cysts in a single institute in Taiwan
Yu-Zu Lin1, Wen-Yih Liang2, Hung-Hsin Lin3, Chun-Chi Lin3, Jeng-Kai Jiang3, Sheng-Chieh Huang3
1 Department of Surgery, Taipei Veterans General Hospital; School of Medicine, National Yang-Ming University, Taipei, Taiwan
2 School of Medicine, National Yang-Ming University; Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
3 School of Medicine, National Yang-Ming University; Division of Colon and Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan
|Date of Submission||05-Jun-2018|
|Date of Decision||01-Aug-2018|
|Date of Acceptance||05-Aug-2018|
Department of Surgery, Division of Colorectal Surgery, Taipei Veterans General Hospital, No 201, Sec 2, Shih-Pai Road 11217, Taipei
Source of Support: None, Conflict of Interest: None
Background: Tailgut cysts are rare congenital lesions that are generally located in the retrorectal regions. We performed a cases series in Taiwan to compare with others.
Materials and Methods: The demographics, clinical presentation, surgical management, pathological features, and long-term outcome of 14 patients of tailgut cysts diagnosed at Taipei Veterans General Hospital from 1989 to 2018 were reviewed.
Results: In this series, 11 patients (78.6%) were female with the mean age of 46.7 (18–75) years. The majority of cases (83.3%) were symptomatic with variable manifestations. All patients received radiological examination and/or endoscopy. One case underwent biopsy before the therapy. Surgical methods included Kraske, transanal, abdominal, and combined approaches. Tailgut cysts were benign in ten patients (71.4%) and malignancy included mixed adenoneuroendocrine carcinoma, carcinoid tumor, and borderline mucinous tumor. No long-term adverse effect was reported. There was no recurrence of benign tailgut cysts during the median follow-up of 3 years.
Conclusion: Tailgut cysts are uncommon and diagnosed predominantly in the middle-aged female. They can present with variable clinical manifestations, and diagnosis relies on image study. A routine preoperative biopsy is not indicated as it can be uninformative or false negative. Complete surgical excision is recommended even in asymptomatic cases for definite diagnosis and the possibility of malignant transformation. A variety of surgical approaches can achieve complete surgical removal and avoid recurrence if being planned ahead by image carefully.
Keywords: Mixed adenoneuroendocrine carcinoma, retroretal tumor, tailgut cyst
|How to cite this URL:|
Lin YZ, Liang WY, Lin HH, Lin CC, Jiang JK, Huang SC. Management of tailgut cysts in a single institute in Taiwan. Formos J Surg [Epub ahead of print] [cited 2019 Feb 16]. Available from: http://www.e-fjs.org/preprintarticle.asp?id=250872
| Introduction|| |
A tailgut cyst, also known as a retrorectal cyst hamartoma, is a rare, congenital, and developmental cyst. It was reported with the incidence of 1/40,000 patient admissions. It develops from postanal remnants of the hindgut. Being a portion of the primitive gut, the tailgut lies caudally to the cloacal membrane. It is formed during the 4th week of gestation and regresses completely by the 8th week of gestation. If the tailgut fails to regress, remnants of it would evolve into congenital cysts.
Tailgut cysts are usually located in retrorectal region, while prerectal space, perirenal space, and other parts of the body have also been reported. The retrorectal region, or presacral region, is a potential space, which is bounded anteriorly by mesorectum, posteriorly by sacrum (Waldeyer's fascia), superiorly by peritoneal reflection, inferiorly by rectosacral fascia, and laterally by ureters, iliac vessels, sacral nerve roots, and lateral stalks of the rectum. The retrorectal space contains loose connective tissues, middle sacral vessels, iliolumbar vessels, middle hemorrhoidal vessels, branches of sympathetic and parasympathetic nerve systems, and lymph ducts. The lesions within the retrorectal space can be divided into congenital, inflammatory, neurogenic, osseus, and miscellaneous diseases. Developmental cysts are one kind of congenital disease, and they are the most common lesions in the retrorectal space. The developmental cysts can be further classified into dermoid, epidermoid, and enteric cysts according to the pathology component. Tailgut cyst is one type of the enteric cysts, whereas cystic rectal duplication is the other type, including the neurenteric cysts.
Although tailgut cysts can present at any age, they are usually diagnosed between 30 and 60 years of age. There is female predominance, with female-to-male ratio ranging from 3:1 to 9:1.,, They are usually asymptomatic at diagnosis and discovered incidentally during physical or radiological examinations. Tailgut cysts may pose local effects that cause symptoms including constipation, rectal fullness, pain during defecation, rectal pain, rectal bleeding, change in stool caliber, lower abdominal pain, low back pain, dysuria, and urinary frequency. They can also present with other complications such as infection with fistulization, bleeding, and malignant transformation. Computed tomography (CT) or magnetic resonance imaging (MRI) is usually used for diagnosis and surgical planning. Intrarectal ultrasonography can also provide effective information for differentiation of the lesion. Complete surgical resection is the recommended management. There are many ways of surgical approach, with abdominal (anterior), transsacral (posterior), and combined abdominosacral methods being adopted most frequently.
Several small case series were reported. However, in recent 30 years, most of the articles discussing about the tailgut cyst were case reports. Therefore, in view of the rarity of the disease, we present 14 cases of tailgut cysts, all of whom underwent surgical resection in Taiwan. The demographics, presentation, image, and pathology are demonstrated.
| Materials and Methods|| |
We retrospectively reviewed the medical records of 14 patients who had histologically confirmed tailgut cysts collected from the database of the Department of Pathology, Taipei Veterans General Hospital between 1989 and 2018.
Patients' demographics, clinical presentation, surgical management, pathological features, and subsequent follow-up were recorded and analyzed. CT, MRI, and endoscopic examination, when performed before the operation, were reviewed. The surgical procedure was determined by each surgeon's judgment. All patients were followed by endoscopy, CT, or MRI at least once during the first 3 months after the surgery.
Results are presented as median numbers (minimal and maximal range) for continuous variables and numbers (percentages) for categorical variables.
The study was conducted in accordance with the Declaration of Helsinki and was approved by the local ethics committee of the institute. Informed written consent was obtained from all patients prior to their enrollment in this study.
| Results|| |
There were 14 patients who were diagnosed with the tailgut cysts between 1989 and 2018 in Taipei Veterans General Hospital. Due to the retrospective nature of the study, some of the information regarding three of the 14 patients could not be traced. These lost data were excluded from the analysis.
The mean age at the time of surgery was 46.7 (18–75) years. Eleven patients (78.6%) were women. Clinical manifestation is summarized in [Table 1]. The lesion was palpable by digital rectal examination in most of the cases (9,81.8%). Nine patients (81.8%) received preoperative radiological examination including abdominal ultrasound (2,22.2%), CT (6, 66.7%), and MRI (6,66.7%). Seven patients (63.6%) underwent colonoscopy or sigmoidoscopy. All patients received one of the radiological examinations, sigmoidoscopy, and colonoscopy before the operation. Initial diagnosis before the surgery included tailgut cyst (3,27.3%), epidermoid cyst (1,9.1%), teratoma (1,9.1%), retrorectal cystic tumor (1,9.1%), gastrointestinal stromal tumor (1,9.1%), anal submucosal tumor (1,9.1%), rectal submucosal tumor (1,9.1%), rectal cancer (1,9.1%), and recurrence of rectal adenocarcinoma (1,9.1%).
The operative approach was performed by the Kraske procedure in six patients (50%), transanal approach in three patients (25%), and abdominal approach in two patients (16.7%) [Table 2]. A combined approach (abdominal and Kraske) was used for one patient (8.4%). Seven tumors (63.6%) were loculated, and four tumors (36.4%) were single. In four cases (36.4%), the tumors were either drained intraoperatively to facilitate resection or ruptured during dissection. Median amount of blood loss was 150 (30–300) ml for Kraske procedure, minimal loss (<30 ml) for transanal approach, 250 (100–400) ml for abdominal approach, and 1950 ml for combined approach (one case). There was no postoperative mortality. In patients who received Kraske procedure, one had perianal hematoma requiring reoperation, one had superficial punctate keratitis OU due to the prolonged prone posture which was treated with topical agents, and one had rectal perforation during dissection which was repaired intraoperatively. One of the patients who had transanal excision developed anastomosis leakage which was treated conservatively. Another patient who received surgery by abdominal approach had incarcerated ventral hernia needing reoperation on postoperative day 3. The patient who underwent combined approach had massive bleeding from pelvic venous plexus during the operation, and it was controlled intraoperatively.
The median maximal diameter of the cysts was 73 (27–120) mm. The smallest was 27 mm × 12 mm × 5 mm, and the largest was 120 mm × 100 mm × 100 mm based on the histological examination. Ten (71.4%) patients had benign tailgut cysts. Two patients had borderline mucinous tumor components, one had carcinoid tumor, and one had mixed adenoneuroendocrine carcinoma in the cyst [Table 3]. Most of the cysts had variable epithelial lining, including squamous (8,72.7%), columnar (9,81.8%), and transitional epithelium (1,9.1%). There were smooth muscle cell bundles in the cyst wall in most cases (10,90.9%). Inflammation of the cysts was presented in 11 (78.6%) patients. Within the six patients who had bacterial culture for the cystic contents, three patients (50%) had positive culture result. The identified organisms included Escherichia coli, Klebsiella pneumoniae, Fusobacterium mortiferum, and Bacteroides fragilis, with E. coli being the most common bacteria (3,100%).
The median follow-up was 3 years (1.5 months to 23 years). No long-term adverse effects were reported after the operations. There was no recurrence of the benign tailgut cysts. Among the four patients with malignant degeneration, the one who had mixed adenoneuroendocrine carcinoma died at 11 months, despite of chemotherapy, while the rest of the patients remained disease-free during follow-up.
| Discussion|| |
This series represents 14 cases of tailgut cysts at our institution during the past 29 years. Most cases were middle-aged female (78.6%). There was a variety of clinical manifestation, and most of them were asymptomatic until tailgut cysts were diagnosed (83.3%). All patients received radiological examination and/or endoscopy survey. Only one case underwent biopsy before the surgery. Surgical approaches varied, with Kraske procedure being adopted most frequently (42.9%). Tailgut cysts had variable epithelial lining even within one cyst; the predominance of them was columnar epithelium, while most of them contained smooth muscle cell bundles in the wall (90.9%). Inflammation was also found in most of the cysts (78.6%). Tailgut cysts were benign in the most cases (71.4%) in our series, and half of the cysts were sent for bacterial culture with negative results. Among those culture-positive cysts, E. coli were the predominated species (100%). No long-term adverse effect and no recurrence were reported in our series at the median follow-up of 3 years.
One patient in our series had mixed adenoneuroendocrine carcinoma (MANEC) in the tailgut cyst. The case underwent Kraske procedure to excise the lesion. However, the tumor metastasized to the right inguinal lymph nodes and pituitary gland proved by biopsy in 2 and 4 months later. Radiotherapy and chemotherapy were then arranged for her with cisplatin and etoposide. The response to the therapy was poor, and the patient died at 11 months later which showed poor prognosis of the disease. Malignant transformation of the tailgut cysts that has been reported includes adenocarcinoma, neuroendocrine carcinoma, endometrioid carcinoma, adenosquamous carcinoma, squamous cell carcinoma, sarcoma, and transitional cell carcinoma., The majority is adenocarcinoma. Tracing back to the literature review, this is the first report of MANEC within the tailgut cysts and presented with the poor prognosis under surgical therapy, radiotherapy, and chemotherapy.
In 2010, the World Health Organization defined the MANEC as tumors consisting of both exocrine and endocrine components with each accounting for at least 30% of the tumors., The pathology of the MANEC in our series revealed a cystic lesion lined by a single glandular epithelium with solid mass in the lumen. Most of the glandular epithelium showed a picture of adenocarcinoma, while the solid mass showed neuroendocrine carcinoma with stromal infiltration. MANECs have been described in the esophagus, stomach, gallbladder, bile duct, ampullary, pancreas, colon, cecum, and anorectal region., The prognosis depends on neuroendocrine tumor if they are poorly differentiated and depends on exocrine tumor if the neuroendocrine tumor is well differentiated. Due to the rarity of the disease, the optimal management have not been documented. Treatments are commonly analogous to adenocarcinoma or neuroendocrine carcinoma, depending on which component is more aggressive.
A review of all patients with histopathologically proven tailgut cysts at our institution during the past 29 years revealed only 14 cases, which is consistent with the rarity of the disease entity. Our cases were similar to those previously reported in the literature with respect to middle age and female predominance., In contrast, the majority of patients in this study were symptomatic at diagnosis (83.3%). One explanation is the referring cases for further management with symptoms. There were five cases referred from other specialties and institutions, with four having symptoms for treatment. Only one asymptomatic case was referred soon after incidental image diagnosis. The presence of symptoms may be related to large cyst with adjacent organ or tissue compression.
All patients in our series received endoscopy and/or radiological examination, including abdominal ultrasound, CT, and MRI. The decision of which modality that would be used depended on each patient's clinical manifestation, medical history, and physical finding. CT and MRI can aid in diagnosis and surgical planning by identifying the tumor location, size, and contents, along with the relationship with adjacent structures and the risk of malignancy. MRI has the advantage over CT of soft-tissue details, and accurate diagnosis avoids the need for routine biopsy. Two patients in our study received diagnostic laparoscopy before referral based on the ultrasound finding of gynecologic tumors. This suggested that ultrasound as the sole preoperative image modality might not be able to delineate the structure of cystic tumors in the pelvis and the associated anatomy well, especially for women, in whom adnexal tumors can complicate the differential diagnoses., Two out of six patients who received MRI were diagnosed as tailgut cyst initially, while the remaining diagnoses included retrorectal cystic tumor, epidermoid cyst, rectal cancer, and GIST. The relatively low rate of correct diagnosis based on MRI may be related to the rarity of tailgut cyst, small tumor size of the presumed rectal cancer, and a wide variety of differential diagnoses of retrorectal cystic tumor, which includes epidermoid cyst, dermoid cyst, rectal duplication cyst, anal gland cyst, cystic lymphangioma, and anterior meningocele. The distinction between the tailgut cyst and other cystic tumor is necessary due to the potential for malignant transformation. Thus, histopathological diagnosis of presacral cystic tumor is sometimes required when the malignant potential is highly suspected.
However, the role of routine preoperative biopsy is controversial. Biopsy carries the risk of bleeding, nerve injury, infection, and dissemination of tumor cells if it is malignant. In addition, biopsy can be uninformative or false-negative, and there were technical difficulties of biopsy because of the sacrum. The routes of biopsy that have been described include transgluteal approach through greater sciatic foramen, transrectal, parasacral, and precoccygeal approaches. Moreover, tailgut cysts carry the risk of infection and malignant degeneration. In general, most of the authors agree that routine preoperative biopsy is not indicated. Biopsy can be considered if the image suggests that the tumor has malignant features and is locally invasive that prevents it from complete excision., Only one case in our study received preoperative biopsy. She had transanal biopsy twice based on the initial diagnosis of GIST; however, both procedures showed no pathological diagnosis. Besides, due to the pus drained during the second biopsy, diagnosis was adjusted as infected epidermoid cyst. This suggested that preoperative histopathological diagnosis is difficult without definite surgical resection to get the entire specimen.
A variety of surgical approaches to tailgut cysts have been well described in the literature. Surgical treatments can be classified into three groups of approaches as follows: anterior (transabdominal), posterior (intersphincteric, transsphincteric parasacrococcygeal, transsacral, transsacrococcygeal, transanorectal, and transvaginal), and a combination of both., Minimally invasive surgery including laparoscopic transabdominal approach and transanal endoscopic approach has also been reported., The appropriate surgical approaches are determined by the morphology, location, and size of the tumor, and the relationship between tumor and surrounding structures. The abdominal, transsacral, and combined abdominosacral approaches were adopted most frequently. Our study demonstrated that transanal approach is feasible for tailgut cyst if being selected appropriately, with minimal blood loss, low rate of rupture and postoperative complication, no recurrence, and no long-term adverse effect.
Tailgut cysts are lined with a variety of epithelia, including stratified squamous, transitional, stratified columnar, mucinous or ciliated columnar, ciliated pseudostratified columnar, and gastric type epithelium. The variation can be seen in different cysts or in the same cyst. The cyst wall usually contains focal, well-formed, and disorganized smooth muscle cells., These characteristics distinguish tailgut cysts from other retrorectal cystic tumors such as epidermoid cyst, dermoid cyst, and duplication cyst. Besides, the cysts are usually filled with fluid that presents in various color and thickness. Our study is consistent with these features. In addition, columnar epithelium is the most common type. The cystic fluid, when being described, varied from mucin, chocolate, to sebum, pus, and abscess.
Tailgut cysts can be complicated with infection. They can be misdiagnosed as perianal, gluteal, or presacral abscess, especially when a fistula tract is formed. The rate of infected tailgut cysts at diagnosis, no matter symptomatic or asymptomatic, ranged from 10 to 76%., If a patient had multiple operations for recurrent abscess or fistula-in-ano, tailgut cysts should be taken into consideration. Of the six patients who had bacterial cultures, three yielded positive culture results, including Gram-negative bacteria and anaerobes. Besides, two patients had mixed bacterial growth. These conditions suggest that most of the bacteria are from the intestinal tract. Although the presence of bacteria does not necessarily mean infection at diagnosis, this result might serve as a guide for empirical antibiotic regimen if infection is clinically suspected.
Most of the tailgut cysts are benign disease. The rate of malignant transformation varied greatly between studies. In the largest series including 53 cases, the rate of malignancy was 2%, while it could range from 13% to 40% in other smaller-scaled reports., The rate of malignant degeneration in our study was 28.6%.
The risk of malignant transformation has no relation with the clinical symptoms, bacterial growth, or role of inflammation in tailgut cysts. More cases are needed to study the relationship between one another.
Few studies addressed the recurrence of tailgut cysts, and there were no standardized methods of postoperative surveillance. Recurrence of benign tailgut cyst has been reported to range from 0 to 16%. The interval of the index operation and clinical or image evidence of recurrence was between 4 months and 13 years.,,, No recurrence of benign tailgut cyst was found during median follow-up of 3 years in this study.
The limitations of our study include its retrospective nature, single center, and small sample size. In addition, these patients received different strategies of preoperative evaluation, as well as postoperative surveillance. The consideration of each surgical approach was not recorded in detail. Further data are still needed to see the whole picture of the rare disease.
| Conclusion|| |
Tailgut cysts are rare and generally located in retrorectal region. They are diagnosed predominantly in middle-aged female and can present with a variety of clinical manifestations. Diagnosis relies on image study, and routine preoperative biopsy is not indicated as it can be uninformative or false-negative. Complete surgical excision is recommended even in asymptomatic cases for definite diagnosis and the possibility of malignant transformation. Transabdominal, Kraske, transanal, and combined approaches can achieve complete surgical removal and avoid recurrence if being planned ahead by image carefully.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]