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.

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Background Extended excision of the permeation organ neighborhood is often performed in locally invasive colon cancer, and it is reported to have a survival benefit. In addition, some cases of secondary lymph node metastases in a permeation organ were reported. However, they are reports of synchronous secondary lymph node metastases, not metachronous secondary lymph node metastases. To the best of our knowledge, there are no cases of metachronous secondary lymph node metastases after the resection of a primary colorectal cancer in PubMed. Case presentation The case was a 67-year-old man who underwent colonoscopy because of weight loss. Sigmoid colon cancer with all circumference-related stenosis was found by examination, and the patient was transferred to our hospital for the purpose of scrutiny and treatment. The small intestine ileus caused by the invasion of sigmoid colon cancer developed after the transfer. Laparoscopic high anterior resection and extended excision of small intestine segmental resection was performed after the intestinal tract decompression with a nasal ileus tube. Histopathological analysis revealed a pathological diagnosis of pT4b (ileal submucosal invasion) N0 (0/11) M0 f Stage II, tub2, ly1, v2, PN0. Although adjuvant chemotherapy with capecitabine after the operation was planned for half a year, treatment was suspended in the first course by the patient’s self-judgment. No recurrence was observed for a year after the operation, but metastasis recurrence in the para-aortic lymph node was found by a computed tomography (CT) one and a half years after the operation. 18 F-fluorodeoxyglucose (FDG) positron emission tomography revealed that FDG was accumulated only in the para-aortic lymph node. Laparoscopic metastasis lymphadenectomy was performed due to the diagnosis of metachronous metastasis to the para-aortic lymph node alone. Intraoperative findings revealed that lymph node metastasis occurred in the mesentery of the ileum. No adjuvant treatment was done after the secondary operation, and he is still alive with no recurrence 1 year and 9 months after the operation. Conclusions We report a rare case of a laparoscopic resection of a metachronous secondary lymph node metastasis in the mesentery of the ileum after surgery for sigmoid colon cancer with ileum invasion.

Background Undifferentiated pleomorphic sarcoma (UPS) is a malignant soft tissue tumor that has been reclassified from malignant fibrous histiocytoma with the development of the pathological diagnosis. It principally occurs in the extremities but rarely occurs in the rectum. We herein report a rare case of UPS arising in the rectum. Case presentation A 85-year-old woman was referred to our hospital with a complaint of anal pain, which had persisted for several months. Computed tomography (CT) showed a 53 × 58 × 75 mm mass on the left side of the rectum. Colonoscopy revealed a submucosal elevation in the rectum without any exposure of the tumor to the surface. Contrast-enhanced CT and magnetic resonance imaging revealed an 80-mm mass that originated in the rectal muscular propria, and we suspected a gastrointestinal stromal tumor. No lymph node metastasis or distant metastasis was observed. We performed a laparoscopic Hartmann’s operation. Intraoperatively, severe adhesion around the tumor caused tumor injury and right ureteral dissection. Thus, laparoscopic right ureteral anastomosis and ureteral stenting were additionally performed. The operation time was 6 h and 3 min, and the estimated blood loss was small. The patient was discharged without complications 25 days after surgery. A pathological examination showed that the tumor was composed of highly heterogeneous cells with no specific differentiation traits, leading to a diagnosis of UPS. Contrast-enhanced CT performed 2 months after surgery showed bilateral pelvic lymph node enlargement, which indicated recurrence. Considering the patient’s age, we performed radiotherapy (50 Gy/25 Fr targeting the pelvic region). At present, 16 months have passed since the completion of radiotherapy. Contrast-enhanced CT shows that the recurrent lymph nodes have disappeared, and no new distant metastasis has been observed. Conclusions We reported a case of UPS arising in the rectum. The surgical procedure and indication of preoperative therapy should be carefully selected because complete removal of the tumor is desirable in UPS.