Choroid plexus papilloma (CPP) is a rare benign intracranial tumor origin that predominantly manifests in the lateral ventricle in children, accounting for 0.3%-0.6% of all primary intracranial tumors. It is extremely rare to have the CPP in the trigone of the lateral ventricle through the contralateral posterior interhemispheric transfalcine transprecuneus approach (PITTA). Herein, we report this rare case. A 7-year-old girl presented with headache. Magnetic resonance imaging of the brain showed periatrial lesions, and histopathological examination confirmed CPP (WHO grade I). The contralateral PITTA is a safe, effective, reasonable, and appropriate for some lesions in the trigone of the lateral ventricle. It provides a wider surgical angle (especially for the lateral extension) and reduces the risk of disturbance of the optic radiation compared with the conventional approaches. The use of multiple modern neurosurgical techniques, including interventional embolization, intraoperative navigation, microscope, and electrophysiological monitoring, make the procedure much easier and more accurate, and the neuroendoscope adds to the visualization of the microscope and can reduce surgical complications.

Evidence suggests the bladder trigone to be a potential organ at risk (OAR) in predicting acute and late genitourinary (GU) side effects when treating prostate cancer with radiotherapy.
A search of MEDLINE, Cinahl, EMBASE, PubMed, the Cochrane Database of Systematic Reviews and OpenGrey was conducted and no current or underway systematic reviews or scoping reviews on the topic were identified. A systematic literature review was carried out assessing the quality of this evidence. All evidence that prospectively or retrospectively reviewed radiotherapy or modelled radiotherapy dose to the bladder trigone were included. The search was conducted on the 8th July 2021 with 32 studies included in this review. This was repeated 10th June 2023 and two additional studies were identified. Any evidence published since this date have not been included and are a limitation of this review.
MRI imaging is recommended to assist in delineating the trigone which has been shown to have a high amount of inter-observer variability and the use of specific training may reduce this. Across all radiotherapy treatment modalities, trigone dose contributed to GU acute and late toxicity symptoms. Trigone motion is relative to prostate motion but further research is required to confirm if the prostate can be used as a reliable surrogate for trigone position. The dose tolerance given for specific trigone related toxicities is debated within the literature, and on analysis the authors of this review suggest bladder trigone dose limits: Dmean < 45.8 Gy, V61.0Gy < 40%, V59.8Gy < 25%, V42.5Gy-V41.0Gy < 91% and V47.4Gy-V43.2Gy < 91% with α/β of 3 Gy to reduce acute and late GU toxicities.
There is evidence to support further research into bladder trigone sparing radiotherapy to improve patient outcomes.
Using the bladder trigone as an organ at risk is possible and the authors are currently seeking funding for a feasibility trial to further investigate this.

BACKGROUND: MR-guided radiation therapy (MRgRT) systems provide superior soft tissue contrast than x-ray based systems and can acquire real-time cine for treatment gating. These features allow treatment planning margins to be reduced, allowing for improved critical structure sparing and reduced treatment toxicity. Despite this improvement, genitourinary (GU) toxicity continues to affect many patients.
OBJECTIVE: (1) To identify dosimetric predictors, potentially in combination with clinical parameters, of GU toxicity following SBRT by leveraging MRgRT to accurately monitor daily dose, beyond predicted dose calculated during planning. (2) Improve awareness of toxicity-sensitive bladder substructures, specifically the trigone and urethra.
METHODS: Sixty-nine prostate cancer patients (NCT04384770 clinical trial) were treated on a ViewRay MRIdian MRgRT system, with 40 Gy prescribed to 95% of the PTV in over five fractions. Overall, 17 (24.6%) prostate patients reported acute grade 2 GU toxicity. The CTV, PTV, bladder, bladder wall, trigone, urethra, rectum, and rectal wall were contoured on the planning and daily treatment MRIs. Planning and daily treatment DVHs (0.1 Gy increments), organ doses (min, max, mean), and organ volumes were recorded. Daily dose was estimated by transferring the planning dose distributions to the daily MRI based on the daily setup alignment. Patients were partitioned into a training (55) and testing set (14). Dose features were pre-filtered using a t-test followed by maximum relevance minimum redundancy (MRMR) algorithm. Logistic regression was investigated with regularization to select dosimetric predictors. Specifically, two approaches: time-group least absolute shrinkage and selection (LASSO), and interactive grouped greedy algorithm (IGA) were investigated. Shared features across the planning and five treatment fractions were grouped to encourage consistency and stability. The conventional flat non-temporally grouped LASSO was also evaluated to provide a solid benchmark. After feature selection, a final logistic regression model was trained. Dosimetric regression models were compared to a clinical regression model with only clinical parameters (age, baseline IPSS, prostate gland size, ADT usage, etc.) and a hybrid model, combining the best performing dosimetric features with the clinical parameters, was evaluated. Final model performance was evaluated on the testing set using accuracy, sensitivity, and specificity determined by the optimal threshold of the training set.
RESULTS: IGA had the best testing performance with an accuracy/sensitivity/specificity of 0.79/0.67/0.82, selecting 12 groups covering the bladder (V19.8 Gy, V20.5 Gy), bladder wall (19.7 Gy), trigone (15.9, 18.2, 43.3 Gy), urethra (V41.4 Gy, V41.7 Gy), CTV (V41.9 Gy), rectum (V8.5 Gy), and rectal wall (1.2, 44.1 Gy) dose features. Absolute bladder V19.8 Gy and V20.5 Gy were the most important features, followed by relative trigone 15.9  and 18.2 Gy. Inclusion of clinical parameters in the hybrid model with IGA did not significantly change regression performance.
CONCLUSIONS: Overall, IGA feature selection resulted in the best GU toxicity prediction performance. This exploratory study demonstrated the feasibility of identification and analysis of dosimetric toxicity predictors with awareness to sensitive substructures and daily dose to potentially provide consistent and stable dosimetric metrics to guide treatment planning. Further patient accruement is warranted to further assess dosimetric predictor and perform validation.

BACKGROUND: Tumors originating from the posterior bladder wall can be challenging to diagnose because they may mimic a mass from the uterine cervix. Atypical leiomyoma of the bladder trigone is extremely rare, with few reported cases, and requires caution during surgery to avoid damage to the adjacent ureter. Diagnostic surgery and confirmational pathology are essential to assess whether the tumor is malignant and relieve clinical symptoms. Herein, we describe a case of recurrent leiomyoma with focal atypia in the bladder trigone.
METHODS: A 29-year-old woman with a uterine fibroid incidentally found at a regular checkup was referred to our hospital. Based on magnetic resonance imaging, either urinary bladder leiomyoma or protrusion of pedunculated uterine cervical fibroid into the bladder was suspected. This leiomyoma in the trigone of the bladder was completely excised by laparotomy, and the patient was discharged without complication. Follow-up outpatient ultrasonography identified tumor recurrence after four years. As focal atypia was identified previously, laparotomy was performed to confirm the pathology. A round solid mass was resected from the posterior bladder wall without injuring either ureteric orifice. This tumor was pathologically diagnosed as a leiomyoma without atypia. Three-year follow-up ultrasonography has revealed no recurrence.
CONCLUSIONS: Atypical leiomyoma in bladder trigone is rare and could be easily mistaken for fibroid in the uterine cervix. To confirm histopathology, surgical excision is mandatory and regular follow-up is necessary to detect recurrence.

An entrapped temporal horn (ETH) is one of the critical complications after tumor removal in the lateral ventricle trigone that sometimes becomes life threatening.
We sought to develop a novel intraoperative method of prophylactic intraventricular piping (PIP) just after tumor removal to prevent ETH.
Three patients with meningiomas in the lateral ventricle trigone were treated by a novel intraoperative method of PIP just after tumor removal to prevent ETH. Silicone catheters normally used as ventricular drainage catheters were cut to 5- to 6-cm length and inserted into the tumor cavity to ensure communication between the temporal horn and the atrium or the body of the lateral ventricle through the piping straddling the trigone.
None of our patients developed ETH during the follow-up period without complications caused by the tube placement.
PIP might be beneficial to prevent ETH because constant osmotic pressure and constant cerebrospinal fluid pulse wave transmission are maintained between each compartment of the lateral ventricle.

OBJECTIVE: To determine if reduction in urgency in patients with refractory overactive bladder syndrome (rOAB) is correlated with a reduction in voiding frequency and symptom bother.
METHODS: Data from a prospective series of women with rOAB undergoing radiofrequency ablation of the subtrigonal tissue, termed selective bladder denervation (SBD), was analyzed. Main outcome measures included urgency voids, nonurgency voids, and urgency urinary incontinence (UUI) epidsodes from a 3-day voiding diary and quality of life (QoL) measures (Overactive Bladder Questionnaire Short Form [OAB-q SF]).
RESULTS: The dataset comprised 62 completer subjects at 6 months. Compared to baseline, UUI and urgency voids were lower (P < .001), but nonurgency voids were increased (P < .001) and QoL measures were improved (P < .001), but functional bladder capacity did not increase. At baseline and 6 months post treatment, symptom bother was correlated with urgency voids (P < .05) but inversely correlated with nonurgency voids (P < .001). Urgency and nonurgency voids were inversely related at baseline and at 6 months (P < .0001). Following treatment, urgency voids decreased by 41% and nonurgency voids increased by 33%.
CONCLUSIONS: As with other interventions for OAB, SBD resulted in a reduction in OAB symptoms and an improvement in QoL measures. However, the decrease in urgency voids was offset by an increase in nonurgency voids, suggesting that habit or defensive voiding is a significant driver of urinary frequency. It is not certain if this is a unique finding of the SBD effect, but these data do suggest that analyses of outcomes of other OAB interventions are warranted to gain a better understanding of the genesis of OAB symptoms.

The surgical approach to the atrium of the lateral ventricle remains a challenge because of its deep location and close relationship to important neurovascular structures. We present an alternative and safer approach to lesions of the atrium using a natural pathway through the parieto-occipital fissure. We demonstrate this approach through cadaveric anatomical microdissection and a case series. Five formalin-fixed brain specimens (10 hemispheres) were dissected with the Klingler technique. Transillumination was used to show the trajectory of the approach in cadaveric specimens. Clinical data from five patients who underwent this approach were reviewed. This data included intraoperative ultrasound images, operative images, pre- and postoperative magnetic resonance imaging, MR tractography, and visual field examination. The parieto-occipital fissure is a constant, uninterrupted fissure that can be easily identified in cadavers. Our anatomical dissection study revealed that the atrium of the lateral ventricle can be approached through the parieto-occipital fissure with minor damage to the short association fibers between the precuneus and cuneus, and a few fibers of the forceps major. In our series, five patients underwent total resection of their atrial lesions via the posterior interhemispheric transparieto-occipital fissure. No morbidity or mortality was observed, and the disruption of white matter was minimal, as indicated on postoperative tractography. The postoperative visual fields were normal. The posterior interhemispheric transparieto-occipital fissure approach is an alternative to remove lesions in the atrium of the lateral ventricle, causing the least damage to white matter tracts and preserving visual cortex and optic radiation.

This study is designed to evaluate the histological effects of uropathogenic Escherichia coli (UPEC) infection in the urinary bladder of female rabbits and compare the differences between the dome and trigone. Bacterial cystitis was induced in 13 female rabbits by transurethral inoculation of UPEC into the urinary bladder. Eight animals served as controls. Urine samples were collected by catheterization and cultured for bacterial growth after 12 and 24 hours then every 48 hours. Infection was defined as ≥(1X105) colony-forming unit/ml of UPEC in the first two urine samples. Bladder dome and trigonal specimens were examined by light and scanning electron microscopy eight days after infection. There was a sustained increase in bacterial count, with urethral bleeding and rabbit weakness suggesting bladder colonization in the 10/13 study group (77%). Infection was not demonstrated in two animals and was spontaneously cleared in the third after 48 hours. No control animals developed an infection. In infected rabbits (n = 10), the dome showed inflammatory changes including the epithelial loss or thinning, inflammatory cell infiltration, and congested blood vessels compared to controls. The trigone showed a more pronounced inflammatory response than the dome. The presence of urinary bacterial growth, infection manifestations, and inflammatory changes that were more severe in the trigone than in the dome indicate successful bacterial inoculation and induction of cystitis. This animal model can be used for clinical trials on female cystitis. Our histological findings support a possible role of trigone in the pathogenesis of urinary tract infection.

Episodic (recurrent) macroscopic hematuria in patients with IgA nephropathy is usually associated with a benign prognosis, although some patients experience a transient fall in glomerular filtration rate during the episodes. We present a 15-year-old girl with mild IgA nephropathy who had multiple episodes of macroscopic hematuria associated with severe but transient decreases in estimated glomerular filtration rate, low levels of serum uric acid, and marked increases in fractional excretion of uric acid. Ultrasound studies showed marked inflammatory changes in the bladder, especially involving the trigone. Cystoscopic findings were consistent with these changes. We hypothesize that the macroscopic hematuria may have resulted, at least in part, from hyperuricosuria causing acute irritation of the bladder mucosa in the trigone area.

Lateral ventricular meningioma (LVM) is a rare entity, accounting for 0.5%-5% of all intracranial meningiomas. This type of meningioma arises from meningothelial inclusion bodies in the tela choroidea and/or mesenchymal stroma of the choroid plexus. Although not yet fully characterized, a membranous structure is frequently observed around LVMs. This study analyzed quiescent and activated fibroblast phenotypes in LVMs with focus on the relationship between tumor growth and development of the membranous structure.
This retrospective study analyzed 9 LVM cases for which gross total removal was achieved. Expression of the ependymal cell marker (Forkhead Box J1 [FoxJ1]) was histopathologically evaluated. The distribution of quiescent and activated fibroblasts was also analyzed using anti-fibroblast-specific protein-1 (FSP1)/S100A4 antibody and anti-α-smooth muscle actin (αSMA) antibody, respectively. The control group was 5 cases with primary convexity meningioma for which Simpson grade I removal was achieved.
Small LVMs (≤30 mm) were covered by a FoxJ1-positive(+) ependymal cell monolayer; no αSMA(+) cells were detected in the tumor; and a thick membrane capsule was not observed. None of the convexity meningiomas showed FoxJ1(+) cells. Large LVMs (>30 mm) had thick membrane capsules without an ependymal cell monolayer, which resembled dura mater. The FSP1/S100A4(+) and αSM(+) cells were clearly concentrated in the peripheral area just below the thick dura mater-like membrane capsules.
This study found an association between activated fibroblasts and dura mater-like membrane capsules in LVMs. The characteristics of membranous structure in LVMs may differ depending on tumor size.