Departmental sources 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.

Background: Tailgut cysts arise from the remnants of the tailgut during the embryonic period. Although malignant transition of tailgut cysts is very rarely observed in the clinic, this congenital condition should be carefully monitored for early diagnosis and appropriate treatment, especially when the tailgut cysts are malignant. Case presentation: Here, we report the case of a 33-year-old man with retrorectal adenocarcinoma originating from the tailgut cysts. Magnetic resonance imaging (MRI) showed many cystic masses in the posterior rectal space, the largest of which was approximately 100 mm × 59 mm × 53 mm in size and compressed the rectum. The patient underwent surgical resection of the masses located in the retrorectal and anterior sacral spaces. Histological and immunohistological examinations confirmed adenocarcinoma transition of the tailgut cysts. The patient recovered well and was discharged 10 days after surgery. Conclusions: We have reported a rare case of retrorectal adenocarcinoma originating from tailgut cysts. MRI, histological, and immunohistological examinations are vital for the diagnosis of tailgut cysts. Complete surgical resection of the tumor should be better performed.

Background: Accurate and non-invasive assessment of intracranial atherosclerotic disease (ICAD) is important because of its effect on treatment planning. The aim of this study is to investigate if zero echo time (zTE) magnetic resonance angiography (zTE-MRA) is feasible in the characterization of ICAD.Methods: A total of 175 patients with ICAD were recruited. ZTE-MRA and time-of-flight (TOF)-MRA sequences were conducted for all participants using a 3T clinical MR system. Forty-one patients also underwent digital subtraction angiography (DSA), and were confirmed to have intracranial arterial stenosis (ICAS). Weighted kappa (κ) statistics were used to assess the inter-observer agreement and diagnostic consistency of both zTE-and TOF-MRA, using DSA as a reference. The Wilcoxon signed-rank test was used to evaluate differences in image quality between zTE-and TOF-MRA images. The nonparametric test of multiple paired samples was used to compare the results of vascular stenosis diagnosis between zTE-, TOF-MRA and DSA.Results: Supported by high inter-observer agreement (weighted κ=0.78), zTE-MRA generated significantly higher scores than TOF-MRA for susceptibility artifact signal (mean: 3.03±0.98 vs. 2.72±1.09; P=0.017) and flow signal in parent artery (mean: 3.63±0.49 vs. 3.07±0.82; P<0.001). Additionally, zTE-MRA showed more robust diagnostic performance than TOF-MRA for patients with ICAD and degree of vascular stenosis (P<0.05), and was highly consistent with reference DSA images (weighted κ=0.80).Conclusions: ZTE-MRA has potential for use as a routine clinical method for patients with ICAD.

Background: Post-stroke aphasia (PSA) results from brain network disorders caused by focal stroke lesions. However, it still remains largely unclear whether the impairment is present in intra- and internetwork functional connectivity (FC) within each resting-state network (RSN) and between RSNs in the subacute stage of PSA.Objectives: This study aimed to investigate the resting-state FC within and between RSNs in patients with PSA and observe the relationships between FC alterations and Western Aphasia Battery (WAB) measures.Methods: A total of 20 individuals with subacute PSA and 20 healthy controls (HCs) were recruited for functional MRI (fMRI) scanning, and only patients with PSA underwent WAB assessment. Independent component analysis was carried out to identify RSNs. Two-sample t-tests were used to calculate intra- and internetwork FC differences between patients with PSA and HCs. The results were corrected for multiple comparisons using the false discovery rate (FDR correction, p &lt; 0.05). Partial correlation analysis was performed to observe the relationship between FC and WAB scores with age, gender, mean framewise displacement, and lesion volume as covariates (p &lt; 0.05).Results: Compared to HCs, patients with PSA showed a significant increase in intranetwork FC in the salience network (SN). For internetwork FC analysis, patients showed a significantly increased coupling between left frontoparietal network (lFPN) and SN and decreased coupling between lFPN and right frontoparietal network (rFPN) as well as between lFPN and posterior default mode network (pDMN) (FDR correction, p &lt; 0.05). Finally, a significant positive correlation was found between the intergroup difference of FC (lFPN-rFPN) and auditory-verbal comprehension (p &lt; 0.05).Conclusion: Altered FC was revealed within and between multiple RSNs in patients with PSA at the subacute stage. Reduced FC between lFPN and rFPN was the key element participating in language destruction. These findings proved that PSA is a brain network disorder caused by focal lesions; besides, it may improve our understanding of the pathophysiological mechanisms of patients with PSA at the subacute stage.

Rationale: Adenocarcinoma coexists with adjacent microscopic gastrointestinal stromal tumor (micro-GIST) is rare, especially in the rectum, where the gastrointestinal stromal tumors (GISTs) have the lower incidence rate. It is easy to ignore the concurrent micro-GIST due to the untypical symptoms. Patient concerns: A 77-year-old male patient suffered from lower abdominal pain for 20 days and presented with per rectal bleeding for 10 days. He had the medical history of hypertension and diabetes for more than 25 years. Diagnoses: Endoscopy revealed that the patient had rectum adenocarcinoma and multiple rectum polyps. Besides, the gastrointestinal stromal tumor was diagnosed by the pathologist. Interventions: The patient underwent surgery of laparoscopic rectum resection and prophylactic ileostomy and took 6 courses of Capecitabine tablets orally. Outcomes: One year after surgery, the patient had no local relapse by the CT scan. However, not long after the CT examination, he died of cardiovascular disease. Lessons: Although micro-GIST may be noninvasive and asymptomatic, it may have the potential for transforming to malignancies. More attention should be paid to the patients diagnosed with gastrointestinal malignancy coexisting with micro-GIST.