Ghrelin-producing well-differentiated neuroendocrine tumor (carcinoid) of tailgut cyst. Morphological, immunohistochemical, ultrastructural, and RT-PCR study of a case and review of the literature

A neuroendocrine tumor arising in a tailgut cyst: Case report and literature review

INTRODUCTION AND IMPORTANCE

Cystic lesions in the retrorectal space include developmental abnormality, inflammatory process, and tumor-relevant cysts. Among them, the tailgut cyst is the most common lesion which is featured by the complex epithelium lining the wall. It is generally accepted that tailgut cysts are embryonic residues and are mostly benign, but there are also reports about malignant transformation and even metastasis.

CASE PRESENTATION

A 44-year-old female complained a sacrococcygeal discomfort more than one year. The imaging diagnosis was an infectious cyst. After surgery, a solid region was defined in a cyst. Morphologically, the region was composed of bland epithelia forming glandular or ribbon-like structure, with round nuclei and fine chromatin. Immunohistochemically, the cells were positive for CK7, CD56 and synaptophysin. The Ki-67-positive cells were about 1 %. The final diagnosis is a low-grade neuroendocrine tumor arising in a tailgut cyst. The patient was living without recurrence by the follow-up of 20 months after surgery.

CLINICAL DISCUSSION

By reviewing the previously reported NET arising from tailgut cysts, we summarized 29 cases of neuroendocrine neoplasms that reported detailed information, and the majority are women. We found that the higher-grade tumor presented a higher tendency of distant metastasis or recurrence after surgery. Complete resection and full evaluation by pathologists are necessary to get a correct diagnosis and avoid disease progression.

CONCLUSION

We reported the rare case of NET G1 arising from a tailgut cyst and reviewed relevant reports, in order to broaden differential diagnoses when an isolated mass is identified in the retrorectal space.

Analysis of the clinicopathological features of tailgut cyst with emphasis on the development of neoplastic lesions

Tailgut cyst is a rare congenital cyst occurring in the retrorectal space and development of neoplastic lesions in tailgut cyst has been reported. Due to the rarity of the tumor, the histogenesis of neoplastic lesions in tailgut cyst has remained elusive. In the present study, the clinicopathological features of tailgut cyst were analyzed with a particular focus on the development of neoplastic lesions. The clinicopathological features of four patients with tailgut cyst (one female and three males) were retrospectively reviewed. No symptoms were present in two patients. Perineal discomfort, and constipation and urinary retention, were described in the other two patients, respectively. Magnetic resonance imaging showed that the cystic lesions were hypointense on T1- and hyperintense on T2-weigted images in all patients. Histopathological analysis revealed that all lesions were multilocular, and cystic walls were covered by squamous and ciliated epithelia without nuclear atypia. The development of neoplastic lesions was noted in two patients. Dysplastic change composed of piling-up proliferation of glandular cells with mild to moderate nuclear atypia was present in one patient, and invasive adenocarcinoma with a dysplasia component was observed in another patient. Dysplasia of the glandular cells, as seen in two patients in the present series, may be a precursor lesion of invasive adenocarcinoma; therefore, adenocarcinoma arsing in tailgut cyst may show a dysplasia-carcinoma sequence. While the reported incidence of neoplastic lesions in tailgut cysts is ~9% or less, their frequency remains to be accurately determined. Therefore, complete surgical resection is important for the management of patients with tailgut cyst. Additional clinicopathological and molecular studies with large cohorts may be required to clarify the histogenesis of neoplastic lesion in tailgut cyst.

Robotic approach to remove four tailgut cyst cases in Brazil: a case series

Tailgut cysts are rare congenital lesions that are remnants of the embryonic hindgut. This abnormality presents with non-specific symptoms or no symptoms; therefore, misdiagnosis is common. Here, we present four cases of tailgut cysts that were successfully removed using a robotic surgical approach. A 42-year-old woman with tenesmus, pain in the right gluteal region, and discomfort in the rectal region during evacuation was referred to our medical center. Another patient was a 28-year-old woman who presented with the same symptoms to our general practitioner. Both patients underwent upper abdominal and pelvic magnetic resonance imaging that revealed a tailgut cyst. Further, a 36-year-old woman was referred with coccyx and hypogastric pain. Magnetic resonance imaging revealed two pararectal cystic formations. She underwent robot-assisted surgery, and after analysis by a pathologist, the conclusion was that the tailgut cyst was associated with scarring fibrosis. A 55-year-old woman with posterior epigastric pelvic pain associated with heartburn underwent robot-assisted surgery to resect a retroperitoneal tumor. These cases highlighted the importance of tailgut cysts in the differential diagnosis of rectal lesions. Surgical treatment is preferred because malignant transformations can occur. The difference between laparoscopic and robotic approaches is the better visualization and stability of the latter, inducing less tissue damage. Robotic resection is a safe procedure, especially in patients with a narrow pelvis, because it reduces tissue damage.

Liver metastases of a neuroendocrine tumor arising from a tailgut cyst treated with interventional locoregional therapies: a case report and review of the literature on recurrent cases

A tailgut cyst is a rare, developmental cyst occurring in the presacral space. Although primarily benign, malignant transformation is a possible complication. Herein, we report a case of liver metastases after resection of a neuroendocrine tumor (NET) arising from a tailgut cyst. A 53-year-old woman underwent surgery for a presacral cystic lesion with nodules in the cyst wall. The tumor was diagnosed as a Grade 2 NET arising from a tailgut cyst. Thirty-eight months after surgery, multiple liver metastases were identified. The liver metastases were controlled with transcatheter arterial embolization and ablation therapy. The patient has survived for 51 months after the recurrence. Several NETs derived from tailgut cysts have been previously reported. According to our literature review, the proportion of Grade 2 tumors in NETs derived from tailgut cysts was 38.5%, and four of the 5 cases of Grade 2 NETs (80%) relapsed, while all eight cases of Grade 1 NETs did not relapse. Grade 2 NET may be a high-risk group for recurrence in NETs arising from tailgut cysts. The percentage of Grade 2 NETs in tailgut cysts was higher than that of rectal NETs, but lower than that of midgut NETs. To the best of our knowledge, this is the first case of liver metastases of a neuroendocrine tumor arising from a tailgut cyst that was treated with interventional locoregional therapies, and the first report to describe about the degree of malignancy of neuroendocrine tumors originating from tailgut cysts in terms of the percentage of Grade 2 NETs.

Neuroendocrine Tumor of Tailgut Cyst with Unexpected Metastases

Neuroendocrine tumors (NETs) originate from the neuroendocrine cells, which are found in various organs. NETs occur frequently in the gastrointestinal tract. NETs arising from tailgut cysts are uncommon. We herein report an interesting case of metastatic tailgut cyst NET, which was firstly diagnosed as plasmacytoma.

Squamous cell carcinoma arising in a tailgut cyst: role of radiotherapy

Tailgut cysts (TGCs) are rare tumours which can undergo malignant transformation. The gold standard of treatment is complete surgical excision. Multidisciplinary assessment is advisable in order to apply adjuvant treatment. Postoperative radiotherapy should be given in case of compromised surgical margins or other factors such as high histological grade or perineural and lymphovascular invasion. Here, we present a case of a squamous cell carcinoma arising from a retrorectal TGC treated with surgery and postoperative radiotherapy and review the main indications and techniques of this therapy.

Promoting Laparoscopic Anterior Approach for a Very Low Presacral Primary Neuroendocrine Tumor Arising in a Tailgut Cyst

Background: Tailgut cysts are rare congenital lesions that develop in the presacral space. As they can potentially conceal primary neuroendocrine tumors, surgical excision is suggested as the treatment of choice. However, specific management guidelines have yet to be developed. A posterior approach is usually preferred for cysts extending to the third sacral vertebral body. Conversely, a transabdominal approach is preferred for lesions extending upward to achieve an optimal view of the surgical field and avoid injuries. Case report: Here, we report a case of a 48-year-old man suffering from perianal pain and constipation. Digital rectal examination and magnetic resonance imaging revealed a presacral mass below the third sacral vertebral body. A laparoscopic transabdominal presacral tumor excision was performed. The final histological diagnosis was a rare primary neuroendocrine tumor arising from a tailgut cyst. The postoperative course was uneventful, and no signs of recurrence were observed at the six-month follow-up. Conclusions: This study may help establish more well-grounded recommendations for the surgical management of rectal tumors, demonstrating that the laparoscopic transabdominal technique is safe and feasible, even for lesions below the third sacral vertebral body. This approach provided an adequate view of the presacral space, facilitating the preservation of cyst integrity, which is essential in cases of malignant pathologies.

Multicenter Analysis of Presacral Neuroendocrine Neoplasms-Clinicopathological Characterization and Treatment Outcomes of a Rare Disease

Background and Aims

Neuroendocrine neoplasms (NENs) of the presacral space are an extremely rare disease entity with largely unknown outcome and no established standard of care treatment. Therefore, we wanted to analyze clinical presentation, histopathological findings, treatment outcomes, and prognosis in a multicentric patient cohort.

Methods

We searched local databases of six German NEN centers for patients with presacral NEN. Retrospective descriptive analyses of age, sex, stage at diagnosis, symptoms, grade, immunohistochemical investigations, biomarkers, treatment, and treatment outcome were performed. Kaplan-Meier analysis was used to determine median overall survival.

Results

We identified 17 patients (11 female, 6 male) with a median age of 50 years (range, 35-66) at diagnosis. Twelve cases presented initially with distant metastases including bone metastases in nine cases. On pathological review the majority of patients had well-differentiated G2 tumors. Immunohistochemical profile resembled rectal NENs. All but one patient had non-functioning tumors. Somatostatin receptor imaging was positive in 14 of 15 investigated cases. Eight patients were treated surgically including palliative resections; 14 patients received somatostatin analogs with limited efficacy. With 14 PRRTs completed, 79% showed clinical benefit, whereas only one patient with neuroendocrine carcinoma (NEC) responded to chemotherapy. Treatment with everolimus in three patients was not successful, whereas cabozantinib resulted in a disease stabilization in a heavily pretreated patient. During a median observation period of 44.5 months, 6 patients died. Median overall survival was not reached.

Conclusion

Presacral NEN are histopathologically similar to rectal NENs. Presacral NEN should be considered as possible primary in NEN of unknown primary. The majority of tumors is non-functioning and somatostatin receptor positive. PRRT demonstrated promising activity; tyrosine kinase inhibitors warrant further investigations. Further molecular characterization and prospective evaluation of this rare tumor entity are needed.

Laparoscopic resection of a neuroendocrine tumor that almost fully replaced tailgut cysts: a case report

Background

Neuroendocrine tumors (NETs) originate from neuroendocrine cells, which are found throughout the body. NETs occur principally in the gastrointestinal tract (approximately 65%) and bronchopulmonary tract (approximately 25%) but rarely occur in the presacral space. Aside from primary and metastatic lesions, there have been reports of NETs occurring in the presacral space arising from tailgut cysts, teratomas, and imperforate anus. We herein report a rare case of laparoscopic resection of a NET in the presacral space, which almost fully replaced tailgut cysts.

Case presentation

A 68-year-old woman was referred to our hospital for surgery of a right inguinal hernia, but preoperative computed tomography revealed an asymptomatic 43-mm mass in the presacral space. Magnetic resonance imaging showed a multilocular solid mass with clear boundaries and a slightly high signal intensity on T1- and T2-weighted images. Positron emission tomography showed 18F-fluorodeoxyglucose uptake. Thus, we suspected a malignant tumor and performed laparoscopic resection to obtain a definitive diagnosis. Macroscopically, the tumor was 43 mm in size with clear boundaries, and the cut surface was a gray-white solid component. Histopathological findings revealed that the tumor was composed of relatively uniform cells with fine chromatin, with round to oval nuclei arranged in solid, trabecular, or rosette-like growth patterns. Small cysts lined with stratified squamous epithelium and columnar epithelium were observed along with solid components of the tumor, which is a feature of tailgut cysts. Therefore, the final diagnosis was NET Grade 1 arising from tailgut cysts. No recurrence was observed within 1 year after surgery.

Conclusions

We performed en bloc laparoscopic resection of a NET arising from tailgut cysts in the presacral space without injury. In cases of a solid lesion in the presacral space, not only the primary disease but also the pathological condition with tissue transformation and replacement should be considered, as in this case.

Tailgut cyst with adenocarcinoma transition: A rare case report

RATIONALE

Tailgut cyst (TGC) is a rare congenital disease that originates from residues of the tail intestine during the embryonic period. Most TGCs are benign lesions and the malignant transition is very rare.

PATIENT CONCERNS

A 50-year-old woman attended our department complaining of defecation difficulty for more than 2 months. She reported irregular defecation with a small amount of liquid stool, 3 to 4 times per day.

DIAGNOSIS

Biochemical analysis showed high levels of carcinoembryonic antigen (79.89 ng/mL; normal, 0-3 ng/mL) and carbohydrate antigen 199 (57.60 U/mL; normal, 0-35 U/mL). Abdominal computer tomography and magnetic resonance imaging showed a large cystic mass with enhanced signals. Post-surgical histopathology indicated that the mass was a TGC with adenocarcinoma transition.

INTERVENTIONS

The cyst was completely resected. Symptomatic treatment was further performed, and the patient recovered well.

LESSONS

We reported a rare case of a large TGC with adenocarcinoma transition. CT, MRI, and histopathology are important to diagnose TGC. Complete surgical resection is the first choice to treat TGC.

Tailgut Cysts with Malignant Transformation: Features, Diagnosis, and Treatment

A tailgut cyst is a type of benign congenital disease that mainly develops in the retro-rectal space. However, malignant transition can occur in some cases of tailgut cysts. Early and precise diagnosis, and proper treatment, are vital for patients with tailgut cysts with malignant transformation. In this review, we aim to summarize the similarities and differences in the diagnosis and treatment methods among the 3 most frequently reported types of tailgut cysts with malignant transformation. In our study, PubMed and Web of Science databases were used to search for the studies and the key words were “tailgut cysts” and “malignancy”. We found 176 articles and selected 75 articles in our survey, with 9 reviews, 35 case reports, and 31 case reports and reviews.

Long-Term Follow-Up of a Patient with Primary Presacral Neuroendocrine Tumor: A Case Report with Literature Review

BACKGROUND Primary neuroendocrine tumors (NETs) in the retroperitoneal space are extremely rare. We report the case of a patient diagnosed with primary presacral NET in the retroperitoneum that was initially suspected to be hepatic metastasis, who was followed up for more than 8 years. CASE REPORT A 78-year-old man was referred to our hospital for the treatment of a hepatic mass. Following resection, the patient was diagnosed with a grade 2 well-differentiated NET. A thorough evaluation to identify the primary tumor detected small well-demarcated presacral nodules on In-111 octreotide single-photon emission tomography/computed tomography (SPECT/CT). Metastases to other locations were not observed. Presacral nodules were difficult to remove using the surgical approach; therefore, we decided to follow up closely. After 4 years, the patient was diagnosed with recurrent hepatic metastasis and peritoneal seeding. Although combination therapy of everolimus and octreotide long-acting repeatable was administered, it was discontinued owing to disease progression. Baseline Ga-68 DOTATOC positron emission tomography-computed tomography revealed adequate avidity for the lesions observed on SPECT/CT; therefore, 5 cycles of peptide receptor radionuclide therapy (PRRT) were administered, after which stable disease was maintained. CONCLUSIONS We identified an extremely rare primary retroperitoneal NET on In-111 octreotide SPECT/CT. During long-term follow-up, although the patient presented with recurrent hepatic metastases and peritoneal seeding, PRRT was successful in stabilizing the disease.

Malignant transformation of tailgut cysts is significantly higher than previously reported: systematic review of cases in the literature

AIM

The best treatment for tailgut cysts has not been firmly established. We report a systematic review of the cases in the available literature in order to provide an evidence base for treatment.

METHOD

A systematic search of articles wholly or partly in English was made of PubMed, Embase and Google Scholar; additional studies were discovered by searching reference lists and contacting authors directly. Search terms 'tailgut cyst', 'tail gut cyst', 'retrorectal hamartoma' and 'retrorectal tumour' were used for case reports or case series; no publication date restrictions were imposed. Only studies with histological confirmation of diagnosis and reporting the age and gender of patients were included. Papers were excluded by consensus between the first two authors.

RESULTS

A total of 196 individual cases were analysed in detail including 51 cases of neoplasia. The overall rate of neoplastic transformation was 26.6%. Although the male:female cyst incidence ratio was 1:4, men over 18 had a significantly greater relative risk of neoplasm at 1.94 (P = 0.0055). Radiological evidence of nodular thickening of the cyst wall significantly increased the relative risk of the presence of cancer (P = 0.0023).

CONCLUSIONS

Current orthodoxy that these are not dangerous embryological remnants is unfounded and may be false. The available data suggest the risk of malignant transformation is high and will apply to any residual tissue after excision. The same rationale behind total mesorectal excision in rectal cancer applies to tailgut cysts. Consequently they should be resected with similar oncological margins.

Primary neuroendocrine tumor in the presacral region: A case report

BACKGROUND

Primary neuroendocrine tumors (NETs) in the presacral region are extremely rare, some of which are caused by other primary tumors or metastatic rectal carcinoids. Nevertheless, cases of NETs have been increasing in recent years. This report describes the first primary neuroendocrine tumor in the presacral region that was found at our hospital within the last five years.

CASE SUMMARY

The patient was identified as a 36-year-old woman with a presacral mass and pelvic floor pain. A digital rectal examination revealed a presacral mass with unclear margins and obvious tenderness. Magnetic resonance imaging (MRI) demonstrated a 57 mm × 29 mm presacral lump. An ultrasound-guided needle biopsy confirmed a well-differentiated neuroendocrine tumor. No other primary or metastatic tumors were found.

CONCLUSION

Comprehensive consideration of our case report and literature reported by others suggests that a conclusive diagnosis of NETs should be based on computed tomography/MRI and pathological examinations. The treatment of primary NETs in the presacral region mainly relies on surgical procedures with follow-up.

Neuroendocrine tumour developing within a long-standing tailgut cyst: case report and review of the literature

A tailgut cyst is a rare congenital lesion that can develop in the presacral space from the remnants of an embryonic hindgut. It is unusual for malignant change to occur in a tailgut cyst. We report a case of a large long-standing tailgut cyst, which was removed during a laparotomy. Histopathology showed a well-differentiated neuroendocrine tumour (primary carcinoid tumour) arising in a tailgut cyst. We reviewed the English literature for all adult cases with this condition. All original articles were reviewed, and data were compiled and tabulated. Including this report, 29 cases of NET developing in a tailgut cyst were found in the English literature. Tailgut cysts have been reported as more common in females, with a mean age of presentation in the fifth decade (Devine, in: Zbar A, Wexner S (eds) Coloproctology. Springer specialist surgery series, Springer, London, 2010; Hjermstad and Helwig in Am J Clin Pathol 89:139-147, 1988). Tailgut cysts may undergo malignant change including adenocarcinoma, sarcoma, and NET (Mathis et al. Br J Surg 97:575-579, 2010; Messick in Dis Colon Rectum 61:151-153, 2018; Patsouras et al. in Colorectal Dis 17:724-729, 2015; Chereau et al in Colorectal Dis 15:e476-e482, 2013). It is difficult to estimate the true incidence of malignant change in a tailgut cyst, with the literature reports only limited to case reports and small-case series. Although rare, our case confirms need to consider the possibility of a malignant component, even in a benign process such as a tailgut cyst. This prompts consideration for upfront definitive management.

Neuroendocrine Tumor Arising in a Tailgut Cyst: A Rare Presacral Tumor

A tailgut cyst (retrorectal cystic hamartoma) is an uncommon lesion that develops in the presacral (retrorectal) space. Malignant change in a tailgut cyst is extremely rare and presents as a soft tissue (presacral) or bone (sacral) neoplasm. We report a case of tailgut cyst in which a neuroendocrine tumor developed in a 25-year-old female. Computed tomography and magnetic resonance imaging scans revealed a sacrococcygeal malformation with absent left S4 and S5 and a partly cystic lesion within the right presacral space. Histologically, the lesion contained cystic and solid elements. The cysts were lined by columnar and stratified squamous epithelial cells with underlying patchy smooth muscle. The solid element was a partly necrotic neuroendocrine tumor composed mainly of ribbons of tumor cells, which showed mitotic activity and expressed cytokeratin, chromogranin, and synaptophysin. Histologically, tailgut cysts are lined by epithelium and contain scattered smooth muscle bundles in the cyst wall. Although rare, the possibility of tailgut cyst with neuroendocrine tumor should be included in the differential diagnosis of an enlarging presacral tumor.

Neuroendocrine carcinoma arising in a tailgut cyst

INTRODUCTION

A tailgut cyst, also called retrorectal cystic hamartoma, is a rare congenital lesion that forms most commonly in the retrorectal space. It is presumed to arise from remnants of early embryogenesis.

PRESENTATION OF CASE

The following report describes a unique case of a retrorectal cystic hamartoma in a 53 year-old French Canadian man with a history of low back pain. The tumour underwent malignant transformation into a well-differentiated neuroendocrine carcinoma three years after the beginning of symptoms.

DISCUSSION

This condition can be found at any age, but occurs especially among middle-aged women. Not only is it frequently misdiagnosed, but also several complications associated to the cyst have been reported such as infection and malignant transformation. This is why complete surgical excision of the tailgut cyst is currently recommended.

Immunohistochemical Biomarkers of Gastrointestinal, Pancreatic, Pulmonary, and Thymic Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs) are a heterogeneous group of epithelial neoplastic proliferations that irrespective of their primary site share features of neural and endocrine differentiation including the presence of secretory granules, synaptic-like vesicles, and the ability to produce amine and/or peptide hormones. NENs encompass a wide spectrum of neoplasms ranging from well-differentiated indolent tumors to highly aggressive poorly differentiated neuroendocrine carcinomas. Most cases arise in the digestive system and in thoracic organs, i.e., the lung and thymus. A correct diagnostic approach is crucial for the management of patients with both digestive and thoracic NENs, because their high clinical and biological heterogeneity is related to their prognosis and response to therapy. In this context, immunohistochemistry represents an indispensable diagnostic tool that pathologists need to use for the correct diagnosis and classification of such neoplasms. In addition, immunohistochemistry is also useful in identifying prognostic and theranostic markers. In the present article, the authors will review the role of immunohistochemistry in the routine workup of digestive and thoracic NENs.

A systematic review of minimally invasive surgery for retrorectal tumors

Retrorectal tumors are rare tumors that require resection for symptoms, malignancy and potential malignant transformation. Traditional approaches have included laparotomy, perineal excision or a combination. Multiple minimally invasive techniques are available which have the potential to minimize morbidity and enhance recovery. We performed a systematic review of the literature to determine the feasibility and surgical outcomes of retrorectal tumors approached using minimally invasive surgical techniques. Publications in which adult patients (≥ 18 years) had a minimally invasive approach (laparoscopic or robotic) for resection of a primary retrorectal tumor were included. Data were collected on approach, preoperative investigation, size and sacral level of the tumor, operating time, length of stay, perioperative complications, margins and recurrence. Thirty-five articles which included a total of 82 patients met the inclusion criteria. The majority of patients were female (n = 65; 79.2%), with a mean age of 41.7 years (range 18-89 years). Seventy-three patients (89.0%) underwent laparoscopic or combined laparoscopic-perineal resection, and 9 (10.8%) had a robotic approach. The conversion rate was 5.5%. The overall 30-day morbidity rate was 15.7%, including 1 intraoperative rectal injury (1.2%). Ninety-five percent (n = 78) of the retrorectal tumors were benign. Median length of stay was 4 days for both laparoscopic and robotic groups, with ranges of 1-8 and 2-10 days, respectively. No tumor recurrence was noted during follow-up [median 28 months (range 5-71 months)]. A minimally invasive approach for the resection of retrorectal tumors is feasible in selected patients. Careful patient selection is necessary to avoid incomplete resection and higher morbidity than traditional approaches.

Well-differentiated neuroendocrine tumor of tailgut cyst. A rare entity with controversial medical opportunities

The incidence of neuroendocrine tumors is rising, and this rise is explained by more than just better diagnostic procedures. About 85% of these neoplasms arise in gastrointestinal or pulmonary sites, but cases where the location is more unusual also occur in clinical practice. The tailgut cyst is a rare entity well described in the medical literature, but a neuroendocrine tumor within such a cyst is a very rare event, with about 30 cases described in the literature to date. In this report we present the case of a young woman with this unusual diagnosis. The characteristics of the case differ from most previous case reports in a few respects: the patient was a young rather than middle-aged female; she had a presacral mass with a significant solid component; at diagnosis, there was evidence of a lytic lesion in the coccyx. Despite this particular medical presentation, radical surgery was accomplished. In this disease the greatest risk is local relapse, but adjuvant radiotherapy may compromise the patient's fertility. We therefore opted for strict control only, but this decision might be debatable.

Retrorectal Tumors: A Comprehensive Literature Review

IMPORTANCE

Retrorectal tumors are rare lesions that comprise a multitude of histologic types. Reports are limited to small single-institution case series, and recommendations on the ideal surgical approaches are lacking.

OBJECTIVE

The purpose of the study was to provide a comprehensive review of the epidemiology, pathologic subtypes, surgical approaches, and clinical outcomes of retrorectal tumors.

EVIDENCE REVIEW

We conducted a review of the literature using PubMed and searched the reference lists of published studies.

RESULTS

A total of 341 studies comprising 1708 patients were included. Overall, 68 % of patients were female. The mean age was 44.6 ± 13.7 years. Of all patients, 1194 (70 %) had benign lesions, and 514 patients (30 %) had malignant tumors. Congenital tumors (60.5 %) were the most frequent histologic type. Other pathologic types were neurogenic tumors (14.8 %), osseous tumors (3.1 %), inflammatory tumors (2.6 %), and miscellaneous tumors (19.1 %). Biopsy was performed in 27 % of the patients. Of these patients, incorrect diagnoses occurred in 44 %. An anterior surgical approach (AA) was performed in 299 patients (35 %); a posterior approach (PA) was performed in 443 (52 %), and a combined approach (CA) was performed in 119 patients (14 %). The mean length of stay (LOS) of PA was 7 ± 5 days compared to 8 ± 7 days for AA and 11 ± 7 days for CA (p < 0.05). The overall morbidity rate was 13.2 %: 19.3 % associated with anterior approach, 7.2 % associated with posterior approach, and 24.7 % after a combined approach (p < 0.05). Overall postoperative recurrence rate was 21.6 %; 6.7 % after an anterior approach, 26.6 % after a posterior approach, and 28.6 % after a combined approach (p < 0.05). A minimally invasive approach (MIS) was employed in 83 patients. MIS provided shorter hospital stays than open surgery (4 ± 2 vs. 9 ± 7 days; p < 0.05). Differences in complication rate were 19.8 % in MIS and 12.2 % in open surgery and not statistically significant.

CONCLUSIONS AND RELEVANCE

Retrorectal tumors are most commonly benign in etiology, of a congenital nature, and have a female predominance. Complete surgical resection is the cornerstone of retrorectal tumor management. A minimal access surgery approach, when feasible, appears to be a safe option for the management of retrorectal tumors, with shorter operative time and length of stay.

Neuroendocrine tumor arising from tailgut cyst with spinal cord tethering: case report and literature review

BACKGROUND CONTEXT

Neuroendocrine tumors (NETs) from tailgut cysts are rare; only 15 cases have been reported until now. A tailgut cyst with spinal cord tethering has not been previously reported, although both diseases are congenital anomalies in the early stage of gestation.

PURPOSE

To report a rare case of NET from tailgut cyst associated with spinal cord tethering and review the literature.

STUDY DESIGN

Case report and literature review.

METHODS

We describe the clinical course of a 53-year-old man, who presented with gluteal pain and bladder dysfunction. Magnetic resonance images showed that a tumor of the sacral spinal canal extended into the retrorectal space and connected to a thickened fatty filum terminale, which was tethering the spinal cord.

RESULTS

Because of tumor malignancy on a computed tomography-guided biopsy and the imaging data of involvement of presacral lymph nodes, we performed total removal of the tumor. Pathologic examination revealed NET (Grade 2) arising from a tailgut cyst. The patient received somatostatin analog therapy after surgery, followed by local radiation because of the further enlargement of the lymph nodes. Later, we started everolimus therapy for the metastases to the retroperitoneal lymph nodes. He presented with no local recurrence or further disease progression at 28 months after surgery. The review indicated that tumors in Grade 2 or 3 showed progressive clinical course after surgery and three of seven patients with biopsy were misdiagnosed.

CONCLUSIONS

The correct preoperative diagnosis of NETs from tailgut cysts is difficult, but extremely important because Grade 2 or 3 tumors show disease progression even after surgery. Presacral congenital tumors, such as tailgut cysts, have the potential of malignant transformation into neuroendcrine tumors or adenocarcinomas. Comorbidity of spinal cord tethering and tailgut cyst suggests some relationship to common developmental errors in embryogenesis.

Ghrelin and obestatin in human neuroendocrine tumors: expression and effect on obestatin levels after food intake

BACKGROUND

Ghrelin and obestatin are derived from the same peptide hormone precursor and are mainly produced by the gastric mucosa. Ghrelin is involved in many biological processes, whereas the physiological function of obestatin needs further investigation. The aims of the present study were to establish the incidence of ghrelin- and obestatin-immunoreactive cells in a comprehensive panel of human neuroendocrine tumors (NETs) and to investigate if blood obestatin concentrations are influenced during a standardized meal stimulation test in healthy individuals and patients with NETs.

MATERIALS AND METHODS

The expression of ghrelin and obestatin was investigated in NETs (n = 149) and other endocrine-related disorders (n = 3) using immunohistochemistry with specific polyclonal antibodies. Coexpression of the peptides was evaluated by double immunofluorescence. Concentrations of obestatin in blood were measured during a meal test in 6 healthy individuals and 5 patients with pancreatic NETs.

RESULTS

Ghrelin and obestatin were expressed in 14/152 and 19/152 tumor tissues, respectively, mainly representing NETs of foregut origin and in pancreatic tissue from a nesidioblastosis patient. Double immunofluorescence staining showed colocalization of the peptides. During the meal test, obestatin levels in blood were unchanged in all patients but decreased significantly in the healthy individuals.

CONCLUSION

Only a minority of NETs express ghrelin and obestatin. However, analysis of patients with tumors originating from tissues that express the peptides in normal conditions could be of importance. The results from the meal test indicate that the hormone levels are affected by food intake in healthy individuals, whereas obestatin levels remained unchanged in pancreatic NET patients.

The ghrelin axis--does it have an appetite for cancer progression?

Ghrelin, the endogenous ligand for the GH secretagogue receptor (GHSR), is a peptide hormone with diverse physiological roles. Ghrelin regulates GH release, appetite and feeding, gut motility, and energy balance and also has roles in the cardiovascular, immune, and reproductive systems. Ghrelin and the GHSR are expressed in a wide range of normal and tumor tissues, and a fluorescein-labeled, truncated form of ghrelin is showing promise as a biomarker for prostate cancer. Plasma ghrelin levels are generally inversely related to body mass index and are unlikely to be useful as a biomarker for cancer, but may be useful as a marker for cancer cachexia. Some single nucleotide polymorphisms in the ghrelin and GHSR genes have shown associations with cancer risk; however, larger studies are required. Ghrelin regulates processes associated with cancer, including cell proliferation, apoptosis, cell migration, cell invasion, inflammation, and angiogenesis; however, the role of ghrelin in cancer is currently unclear. Ghrelin has predominantly antiinflammatory effects and may play a role in protecting against cancer-related inflammation. Ghrelin and its analogs show promise as treatments for cancer-related cachexia. Further studies using in vivo models are required to determine whether ghrelin has a role in cancer progression.

[Surgical management of a retrorectal tumor with consideration of a rare differential diagnosis]

We present a case of a retrorectal space occupying lesion diagnosed as an adenocarcinoma of unknown primary origin by preoperative histopathology. Localization slightly above the anal sphincter would have required extirpation of the rectum. Rectal palpation, endosonography and radiological imaging, however, suggested a retrorectal tumor or a metastasis of an adenocarcinoma. Both entities would have required local resection. We applied a surgical algorithm including frozen biopsy allowing a stepwise choice of operative procedure from the spectrum in question. The operation performed was thus tailored to the entity of the tumor.

[Primary metastatic well-differentiated neuroendocrine tumor arising in a tailgut cyst]

Tailgut cysts are unusual benign cystic retrorectal malformations arising from persistent remnants of the postanal gut. Malignant transformation within this dysontogenetic lesion is very uncommon. We report the rare occurrence of a neuroendocrine tumor arising in a tailgut cyst with primary liver and lymph node metastases in a 55-year-old woman. The neuroendocrine differentiation of the tumor determines the therapeutic approach and prognosis.