Presacral Neuroendocrine Neoplasms: A Multi-site Review of Surgical Outcomes.

INTRODUCTION: Presacral neuroendocrine neoplasms (PNENs) are rare tumors, with limited data on management and outcomes. METHODS: A retrospective review of institutional medical records was conducted to identify all patients with PNENs between 2008 and 2022. Data collection included demographics, symptoms, imaging, surgical approaches, pathology, complications, and long-term outcomes. RESULTS: Twelve patients were identified; two-thirds were female, averaging 44.8 years of age, and, for the most part, presenting with back pain, constipation, and abdominal discomfort. Preoperative imaging included computed tomography scans and magnetic resonance images, with somatostatin receptor imaging and biopsies being common. Half of the patients had metastatic disease on presentation. Surgical approach varied, with anterior, posterior, and combined techniques used, often involving muscle transection and coccygectomy. Short-term complications affected one-quarter of patients. Pathologically, PNENs were mainly well-differentiated grade 2 tumors with positive synaptophysin and chromogranin A. Associated anomalies were common, with tail-gut cysts prevalent. Mean tumor diameter was 6.3 cm. Four patients received long-term adjuvant therapy. Disease progression necessitated additional interventions, including surgery and various chemotherapy regimens. Skeletal, liver, thyroid, lung, and pancreatic metastases occurred during follow-up, with no mortality reported. Kaplan-Meier analysis showed a 5-year local recurrence rate of 23.8%, disease progression rate of 14.3%, and de novo metastases rate of 30%. CONCLUSION: The study underscores the complex management of PNENs and emphasizes the need for multicenter research to better understand and manage these tumors. It provides valuable insights into surgical outcomes, recurrence rates, and overall survival, guiding future treatment strategies for PNEN patients.

Variability in Surveillance Strategies Following Resection of Sacrococcygeal Teratoma.

INTRODUCTION: Surveillance following sacrococcygeal teratoma (SCT) resection varies. The purpose of this study was to describe the clinical characteristics and outcomes of patients undergoing SCT resection and examine current institutional practices to detect recurrence. METHODS: A single-institution retrospective review of children who underwent resection of an SCT from January 1, 2010 to December 31, 2020 was performed. Data were summarized and surveillance strategies compared between histopathologic subtypes using nonparametric methods. RESULTS: Thirty six patients (75.0% female) underwent SCT removal at a median age of 8 d. Histopathology revealed 27 mature teratomas (75.0%), eight immature teratomas (22.2%), and one malignant germ cell tumor (2.8%). Median postoperative follow-up was 3.17 y (interquartile range [IQR]: 2.31-4.38 y). Patients had a median of 2.32 clinic visits per year (IQR: 2.00-2.70), alpha-fetoprotein levels were obtained at a median of 2.01 times per year (IQR: 0-1.66), and surveillance imaging was performed at a median of 2.31 times per year (IQR: 0-2.84). Patients with immature teratomas had alpha-fetoprotein laboratories obtained more frequently than patients with mature teratomas (3.10 times/year versus 0.93 times/year, P = 0.001). There was no significant difference in the number of imaging studies obtained between groups. Two patients (5.6%) developed recurrence, which were identified on magnetic resonance imaging at 191 and 104 d postresection, respectively. CONCLUSIONS: Postoperative surveillance practices varied widely. Recurrence was noted in a single malignant case in the first year following resection. Multi-institutional studies are needed to determine the optimal surveillance strategy to detect recurrence of SCT.

The management of retrorectal tumors - a single-center analysis of 21 cases and overview of the literature.

AIM: Retrorectal tumors are rare and heterogeneous. They are often asymptomatic or present with nonspecific symptoms, making management challenging. This study examines the diagnosis and treatment of retrorectal tumors. METHODS: Between 2002 and 2022, 21 patients with retrorectal tumors were treated in our department. We analyzed patient characteristics, diagnosis and treatment modalities retrospectively. Additionally, a literature review (2002-2023, "retrorectal tumors" and "presacral tumors", 20 or more cases included) was performed. RESULTS: Of the 21 patients (median age 54 years, 62% female), 17 patients (81%) suffered from benign lesions and 4 (19%) from malignant lesions. Symptoms were mostly nonspecific, with pain being the most common (11/21 (52%)). Diagnosis was incidental in eight cases. Magnetic resonance imaging was performed in 20 (95%) and biopsy was obtained in 10 (48%). Twenty patients underwent surgery, mostly via a posterior approach (14/20 (70%)). At a mean follow-up of 42 months (median 10 months, range 1-166 months), the local recurrence rate was 19%. There was no mortality. Our Pubmed search identified 39 publications. CONCLUSION: Our data confirms the significant heterogeneity of retrorectal tumors, which poses a challenge to management, especially considering the often nonspecific symptoms. Regarding diagnosis and treatment, our data highlights the importance of MRI and surgical resection. In particular a malignancy rate of almost 20% warrants a surgical resection in case of the findings of a retrorectal tumour. A local recurrence rate of 19% supports the need for follow up.

Determination of the width of the presacral space on magnetic resonance imaging among adults in south-western Nigeria.

BACKGROUND: The presacral space is a clinically relevant potential space and contents may give rise to a variety of benign and malignant conditions, hence the need for detailed knowledge of its dimensions. PURPOSE: To determine the width of the presacral space and existing variations among adults in south-western Nigeria using a magnetic resonance imaging (MRI) technique. MATERIAL AND METHODS: A total of 369 consenting adults were included in the study. Measurements of the presacral space were then made electronically by consensus of two radiologists. Values derived were recorded and subjected to analyses of variance. RESULTS: The mean normal widths of the presacral space in men and women were 11.7 mm and 11.1 mm at the S1 level, 11.7 mm and 10.35 mm at the S2 level, and 12.3 mm and 9.7 mm at the S3 level, respectively. Measurements of the presacral space width were significantly larger in the male population. Variations in the dimensions due to age greater than 40 years, male sex, and increasing body mass index (BMI) were also noted. CONCLUSION: This study provides baseline dimensions under more physiological conditions and gives more accurate information about the true width of the space in Nigerian adults. Variations due to age, sex, and BMI may also be considered while interpreting abnormal values.

Growth rate of a giant Tarlov (perineural) cyst with intrapelvic extension.

BACKGROUND AND IMPORTANCE: Giant Tarlov cysts (GTCs) are perineural cysts and their presacral intrapelvic extension are extremely rare entities. We present a case of GTC with intrapelvic extension who has preoperative Magnetic Resonance Imaging (MRI) follow-ups of 12 years, and we demonstrate the annual growth rate and the time-size correlation of a GTC. METHODS: Case report. CLINICAL PRESENTATION: A 37-year-old woman was admitted with left gluteal pain radiating to left foot, left leg numbness, progressed over 12 years. On MRI, starting from the L5-S1 level, a giant Tarlov cyst with an atypical configuration, is observed. The patient had a known sacral Tarlov cyst, first discovered on MRI obtained 12 years before the surgery. She had 6 consecutive MRI follow-ups in 12 years preoperatively. The cysts diameters have been measured and the growth rate was estimated. We showed for the first time that presented GTC grows in in both Sagittal Diagonal (SD) and Sagittal Craniocaudal (SC) diameters over time with overall annual growth rates, 7.671% for RGR_SD and 6.237% for RGR_SC. CONCLUSION: When the time-size correlation is observed, it becomes evident that the GTSs' growing speed increases over the years because of minimal resistance in the intrapelvic cavity. Early surgery may be considered to prevent rapid growth in the intrapelvic cavity and to reduce possible complications of the giant cyst.

Surgical outcomes after reoperation for patients with recurrent presacral tumors: a retrospective study.

BACKGROUND: Relevant reports on the surgical resection and prognosis of recurrent presacral tumors are limited. The objective of this study was to explore the outcomes associated with surgical resection of recurrent presacral tumors. METHODS: The data of patients with recurrent presacral tumors who received surgical resection in our hospital between June 2009 and November 2018 were retrospectively analyzed. RESULTS: Thirty-one patients, comprising 22 females and 9 males, with recurrent presacral lesions were included in our study. A posterior approach was utilized in 27 patients, an anterior approach in 1 patient, and a combined approach in 3 patients. Intraoperative complications occurred in 13 patients (41.9%), while postoperative complications occurred in 6 patients (19.4%). The length of hospital stay was significantly shorter in patients who underwent the posterior approach compared to those who underwent the anterior and combined approaches (P = 0.002). The operative time for the posterior approach was significantly shorter compared to both the anterior and combined approaches (P = 0.006). Temporary tamponade was performed for hemostasis in 4 patients, while staged resection was performed in 2 patients during the surgical treatment process. After a median follow-up period of 115.5 months, 5 patients with recurrent malignant presacral tumors succumbed to tumor recurrence after reoperation in our hospital. CONCLUSIONS: Surgical resection remains the mainstream treatment for recurrent presacral tumors. The outcomes for recurrent benign presacral tumors after surgery demonstrate favorable results, whereas further enhancements are required to improve the outcomes for recurrent malignant presacral tumors after surgery.

Robotic resection of presacral tumors.

BACKGROUND: Presacral tumors are a rare entity typically treated with an open surgical approach. A limited number of minimally invasive resections have been described. The aim of the study is to evaluate the safety and efficacy of roboticresection of presacral tumors. METHODS: This is a retrospective single system analysis, conducted at a quaternary referral academic healthcare system, and included all patients who underwent a robotic excision of a presacral tumor between 2015 and 2023. Outcomes of interest were operative time, estimated blood loss, complications, length of stay, margin status, and recurrence rates. RESULTS: Sixteen patients (11 females and 5 males) were included. The median age of the cohort was 51 years (range 25-69 years). The median operative time was 197 min (range 98-802 min). The median estimated blood loss was 40 ml, ranging from 0 to 1800 ml, with one patient experiencing conversion to open surgery after uncontrolled hemorrhage. Urinary retention was the only postoperative complication that occurred in three patients (19%) and was solved within 30 days in all cases. The median length of stay was one day (range 1-6 days). The median follow-up was 6.7 months (range 1-110 months). All tumors were excised with appropriate margins, but one benign and one malignant tumor recurred (12.5%). Ten tumors were classified as congenital (one was malignant), two were mesenchymal (both malignant), and five were miscellaneous (one malignant). CONCLUSIONS: Robotic resection of select presacral pathology is feasible and safe. Further studies must be conducted to determine complication rates, outcomes, and long-term safety profiles.

Cystic lesions of the retrorectal space.

Cysts of the retrorectal space comprise a heterogeneous group of rare lesions. Most develop from embryological remnants and include tailgut cysts, dermoid cysts, rectal duplication cysts, anal canal duplication cysts, sacrococcygeal teratomas and anterior meningocoele. Tailgut cyst is the most common cyst of developmental origin, usually presenting as a multilocular cystic mass with mucoid content and lined by multiple epithelial types. Compared with tailgut cysts, rectal duplication cysts display all layers of the large bowel wall including a well-defined muscularis propria. Retrorectal cysts of non-developmental origin are far less common and represent lesions that either infrequently involve the retrorectal space or undergo extensive cystic change. This review provides an overview of the various histological types of cystic lesions of the retrorectal space, divided into cysts of developmental origin and those of non-developmental origin. A practical pathological and multidisciplinary approach to diagnosing these lesions is presented.

Factors affecting operative morbidity and long-term outcomes in patients undergoing surgery for presacral tumours: a multicentric cohort study from the Turkish Collaborative Group for Quality Improvement in Colorectal and Pelvic Surgery.

AIM: Data regarding the operative management of presacral tumours present various dilemmas due to their rarity and heterogeneous nature. The aim of this study was to evaluate the management strategy, factors associated with operative morbidity and long-term postoperative outcomes in a large group of patients undergoing surgery for presacral tumours. METHOD: This study was designed as a multicentre retrospective cohort study. Records of patients who underwent surgery for presacral tumours at 10 tertiary colorectal centres between 1996 and 2017 were evaluated. RESULTS: One hundred and twenty seven patients (44 men) with a mean age of 46 years and body mass index of 27 kg/m2 were included. Fifty eight per cent of the patients had low sacral lesions (below S3). The operative approaches were transabdominal (17%), transsacral (65%) and abdominosacral (17%). The postoperative morbidity was 19%. Thirty per cent of the patients had a malignant tumour. Longer duration of symptoms (p = 0.001), higher American Society of Anesthesiologists score (p = 0.01), abdominosacral operations (p = 0.0001) and presacral tumours located above S3 (p = 0.004) were associated with an increased risk of postoperative morbidity. Overall long-term postoperative recurrence and mortality were 6% and 5%, respectively, within a 3-year mean follow-up period in patients with presacral malignant tumours. CONCLUSION: Reduced physical condition, omission of symptoms prior to surgery, combined resections and high sacral tumours are the risk factors associated with postoperative complications in patients undergoing surgery for presacral tumours. Meticulous planning of the operation and intensified perioperative care may improve the outcomes in high-risk patients.

Transvaginal natural orifice transluminal endoscopic surgery for presacral-uterosacral ligament compound suspension in apical compartment prolapse.

INTRODUCTION AND HYPOTHESIS: We aimed to describe a novel mesh-free pelvic repair surgery for apical prolapse and to evaluate the effect of this technique and early outcomes. METHODS: We demonstrate the key techniques in a video: exposing the anterior longitudinal ligament (ALL) of the presacral space; securing a non-absorbable suture to the ALL by horoscope stitch; shortening the right uterosacral ligament (USL); placing a non-absorbable suture around the intermediate portion of the left USL for three stitches; placing the non-absorbable suture in the transverse portion of the pubocervical and rectovaginal fascia; locking sutures in place to approximate anterior to posterior connective tissue. Fifteen patients were enrolled to undergo this procedure between December 2020 and April 2021. RESULTS: The mean age of the patients was 60.67 (range 46-69) years, the mean body mass index was 24.25 kg/m2 (range 19.61-30.08). The mean operation time was 103.6 min (range 65-166), and the mean blood loss was 82 ml (range 50-200). No intraoperative complications occurred. All patients gained a significant improvement in anatomical and objective outcomes during a mean 9.93-month follow-up, and there was no recurrence. CONCLUSIONS: Our experience showed that this mesh-free repair surgery was a feasible and safe technique for apical prolapse.

Surgical management of sporadic and schwannomatosis-associated pelvic schwannomas.

Pelvic schwannomas are rare tumors that may occur either sporadically or in the context of schwannomatosis. We retrospectively reviewed the charts of patients harboring a pelvic schwannoma under conservative management or operated at our reference center between 2016 and 2023. All patients were operated by a multidisciplinary team, combining a vascular surgeon and a neurosurgeon. Twenty-four patients harboring 33 pelvic tumors were included in the cohort, including 12 patients with sporadic lesions, 2 patients with NF2-related schwannomatosis, and 10 patients with NF2-independent schwannomatosis. Multi-nodular tumors were more frequent in schwannomatosis compared to sporadic cases (p = 0.005). The mean age at diagnosis was 41 years old. Schwannomas were located on branches of the sciatic nerve (23/33, 70%), the femoral nerve (6/33, 18%), and the obturator nerve (4/33, 12%). Over the course of the study, 16 patients were operated, including 11 sporadic cases. The indication for surgery was pain (12/16, 75%) or tumor growth (4/16, 25%). Complete resection was achieved in 14 of 16 patients (87%). The mean post-operative follow-up was 37 months (range: 2-168 months). At last-follow-up, complete pain relief was achieved in all 12 patients with pre-operative pain. Post-operative morbidity included 3 long-term localized numbness and one MRC class 4 motor deficit in a multi-nodular tumor in a schwannomatosis patient. Despite its limited size, our series suggests that nerve-sparing resection of pelvic schwannomas offers satisfying rates of functional outcome both in sporadic and schwannomatosis cases, except for multi-nodular tumors.

Pediatric presacral tumors with intraspinal extension: a rare entity with diagnostic challenges.

The presacral space is a potential space located between the rectum and the lumbosacral spine. It contains various primitive germ cell types that serve as the origin for a range of tumors. Imaging is crucial in characterizing, assessing the extent of and evaluating the treatment response to these tumors. We report a series of six cases of pediatric presacral tumors with intraspinal extension, including an immature sacrococcygeal teratoma (Altman type II), a malignant sacrococcygeal teratoma (Altman type IV), a neuroblastoma, a rhabdomyosarcoma, a clear cell sarcoma and an Ewing's sarcoma of the ilium. These tumors can be broadly categorized as tumors of germ cell, neuroblastic, mesenchymal and osteogenic origin. Despite overlapping imaging features, a review of the existing literature and careful retrospective observation revealed several distinctive features that aid in the optimal characterization of tumors. These include the tumor's epicenter, the pattern and degree of bone involvement, the status of sacral foramina and neural elements, and internal tumor characteristics such as the presence of fat, calcification, hemorrhage and necrosis.

The characteristics of the urogenital fascia in the retrorectal space based on male cadaveric dissection and its clinical application.

BACKGROUND: The architecture of retrorectal fasciae is complex, as determined by different anatomical concepts. The aim of this study was to examine the anatomical characteristics of the inferomedial extension of the urogenital fascia (UGF) involving the pelvis to explore its relationship with the adjacent fasciae. Furthermore, we have expounded on the clinical application of UGF. METHOD: For our study, we examined 20 adult male pelvic specimens fixed in formalin, including 2 entire pelvic specimens and 18 semipelvic specimens. Our department has performed 466 laparoscopic rectal cancer procedures since January 2020. We reviewed the surgical videos involving UGF preservation and analyzed the anatomy of the UGF. RESULTS: The bilateral hypogastric nerves ran between the visceral and parietal layers of the UGF. The visceral fascia migrated ventrally at the fourth sacral vertebra, which formed the rectosacral fascia together with the fascia propria of the rectum; the parietal layer continually extended to the pelvic diaphragm, terminating at the levator ani muscle. At the third to fourth sacral vertebra level, the two layers constituted the lateral ligaments. CONCLUSION: The double layers of the UGF are vital structures for comprehending the posterior fascia relationship of the rectum. The upper segment between the fascia propria of the rectum and the visceral layer has no evident nerves or blood vessels and is regarded as the " holy plane" for the operation.

Laparoscopic approach for malignant retrorectal tumour: Better vision and lesser morbidity.

The retrorectal tumours are removed by open approaches according to the type, location and size of the lesion. Malignant tumours are mostly operated by open approach owing to the fear of spillage and inability to obtain safe oncological margin. We present our recent experience of laparoscopy for a malignant retrorectal tumour. An 11 cm pre-sacral mass causing erosion of sacrum was operated with a combined approach. Transsacral approach followed laparoscopic mobilisation with the patient in prone jackknife position. Wide excision with sacrectomy was done with adequate margin. Post-operative histopathology showed dedifferentiated chordoma for which adjuvant radiotherapy was given. Laparoscopic approach provides a feasible and oncological safe alternative to the conventional approaches, especially in malignant tumour with advantages of better visualisation, minimal operative morbidity, lesser post-operative pain and shorter hospital stay. However, the surgical approach should be tailored to each patient according to patient factors, tumour characteristics and surgeon's expertise.

Surgical management of sacral schwannomas: a 21-year mayo clinic experience and comparative literature analysis.

INTRODUCTION: Sacral and presacral schwannomas are rare, accounting for a minority of spinal schwannomas. We present our institution's experience surgically treating spinal schwannomas and compare it to the literature. METHODS: Data were collected for 27 patients treated surgically for sacral or presacral schwannoma between 1997 and 2018 at all Mayo Clinic locations and 93 patients in the literature. Kaplan-Meier disease-free survival analysis was conducted. Unpaired two-sample t tests and Fisher's exact tests assessed statistical significance between groups. RESULTS: Our patients and those in the literature experienced a similar age at diagnosis (49.9 y/o. vs 43.4 y/o., respectively). Most of our patients (59.3%) reported full recovery from symptoms, while a minority reported partial recovery (33.3%) and no recovery (11.1%). A smaller percentage in the literature experienced full recovery (31.9%) and partial recovery (29.8%) but also no recovery (1.1%). Our patients experienced fewer complications (14.8% versus 25.5%). Disease-free survival curves for all patients showed no significant variation in progression by extent of resection of schwannoma (log-rank P = 0.26). No lesion progression was associated with full or partial symptom improvement (p = 0.044), and female patients were more likely to undergo resection via a posterior approach (p = 0.042). CONCLUSION: Outcomes of patients with sacral or presacral schwannomas vary based on patient demographics, tumor characteristics, symptoms, and surgical treatment. Among the range of symptoms experienced by these patients, the most common is pain. Prognosis improves and overall survival is high when the surgical approach towards sacral schwannomas is prepared and executed appropriately.

Standard practice of presacral exposure during transvaginal natural orifice transluminal endoscopic surgery for sacrocolpopexy.

We describe the standard practice of presacral exposure during transvaginal natural orifice transluminal endoscopic surgery (vNOTES) for sacrocolpopexy in women with uterine prolapse. In this video, we demonstrate the key techniques: identifying the right hypogastric nerve (rHN) before opening the pelvic peritoneum; removing the fat and loose connective tissue along the rHN to expose the presacral fascia; incising the presacral fascia to reach the presacral space to expose the middle sacral vasculature and the anterior longitudinal ligament (ALL) of the first sacral vertebra (S1) below the promontory; attaching the mesh to the ALL to avoid vessel injury; and completing the peritonealisation.

Long-term outcome after chronic anastomotic leakage following surgery for low rectal cancer.

PURPOSE: This study analyzed the prevalence and factors influencing the history of chronic anastomotic leakage following low anterior resection for rectal cancer. Furthermore, the treatment of a persisting presacral sinus and the impact of stoma reversal on outcome were evaluated. METHODS: The institutional database was scanned for all patients with anastomotic leakage, who were primarily treated for low rectal cancer between January 1995 and December 2019. Patients with rectovaginal and rectovesical fistula or an inadequate follow-up were excluded (n = 5). After applying the exclusion criteria, 71 patients remained for analysis. RESULTS: A total of 39 patients out of 71 patients with anastomotic leakage (54.9%) developed a persisting presacral sinus. Neoadjuvant radiochemotherapy or chemotherapy showed a significant impact on the formation of a chronic anastomotic leakage (radiochemotherapy: p = 0.034; chemotherapy: p = 0.050), while initial surgical treatment showed no difference for anastomotic healing (p = 0.502), but a significantly better overall survival (p = 0.042). Multiple therapies and surgical revision had a negative impact on patients' rate of natural bowel continuity (p = 0.006/ < 0.001). In addition, the stoma reversal cohort showed improved overall 10-year survival (p = 0.004) and functional results (bowel continuity: p = 0.026; pain: p = 0.031). CONCLUSION: Primary surgical therapy for chronic anastomotic leakage should consist of surgical treatment. Furthermore, the reversal of a protective stoma should be considered a viable option in treating chronic presacral sinus to improve pain symptoms and bowel continuity.

Risk of malignancy and outcomes of surgically resected presacral tailgut cysts: A current review of the Mayo Clinic experience.

AIM: The aim of this study was to describe the surgical management, outcomes and risk of malignancy of presacral tailgut cysts. METHOD: A retrospective analysis of all patients who underwent resection of tailgut cyst at Mayo Clinic in Arizona, Florida and Minnesota between 2008 and 2020 was performed. Demographics, presentation, evaluation, surgical approach, postoperative complications, pathology and recurrence rates were reviewed. RESULTS: Seventy-three patients were identified (81% female) with a mean age of 45 years. Thirty-nine patients (53%) were symptomatic, most commonly with pelvic pain (26 patients). Digital rectal examination identified a palpable mass in 68%. Mean tumour size was 6 cm. Resection was primarily performed through a posterior approach (77%, n = 56), followed by a transabdominal approach (18%, n = 13) and a combined approach (5%, n = 4). Six patients underwent a minimally invasive resection (laparoscopic/robotic). Coccygectomy or distal sacrectomy was performed in 41 patients (56%). Complete resection was achieved in 94% of patients. Thirty-day morbidity occurred in 18% and was most commonly wound related; there was no mortality. Malignancy was identified in six patients (8%). For the 30 patients with follow-up greater than 1 year, the median follow-up was 39 months (range 1.0-11.1 years). Local recurrence was identified in three patients and distant metastatic disease in one patient. CONCLUSION: The rate of malignancy in presacral tailgut cysts based on this current review was 8%. Overall recurrence was 5% at a median of 24 months.

Sigmoid conduit-neovaginal fistula: a case report and literature review.

Total pelvic exenterations (TPE) are high morbidity procedures, with up to 38% of patients experiencing a major complication after TPE surgery. We report the case of a 69-year-old woman with a sigmoid conduit-neovaginal fistula who presented with new onset continuous vaginal leakage and decreased urostomy output 3 months post-op from a TPE. We highlight the presentation, diagnosis, conservative management, and surgical management of conduit-vaginal fistulas.

Presacral neuroendocrine tumors associated with the Currarino syndrome.

Currarino syndrome (CS) is an autosomal dominant syndrome caused by mutations in MNX1 and characterized by anorectal abnormalities, partial sacral agenesis, and presacral masses. The presacral masses are typically benign; however, malignant degeneration can occur, and presacral neuroendocrine tumors (NETs) have been reported in six cases. We report three individuals from two families affected by CS in which multiple individuals developed presacral NETs. The first family, 491, had six members with features of CS, including two siblings who presented with presacral, Grade 2 NETs, one of which had metastasized to bone and lymph nodes. A germline c.874C>T (p.Arg292Trp) mutation was found in a highly conserved region of MNX1 in three affected members who underwent sequencing. A second somatic variant/deletion in MNX1 was not detected in either patient's tumor. In the second family, 342, the proband presented with an incidentally discovered presacral NET. The proband's father had previously undergone resection of a presacral NET, and so genetic testing was performed, which did not reveal an MNX1 mutation or copy number variants. The lack of a second, somatic mutation in the tumors from family 491 argues against MNX1 acting as a tumor suppressor, and the absence of a germline MNX1 mutation in family 342 suggests that other genetic and anatomic factors contribute to the development of presacral NETs. These cases highlight the variable presentation of CS, and the potential for malignancy in these patients.