Transperineal core-needle biopsy of a rectal subepithelial lesion guided by endorectal ultrasound after contrast-enhanced ultrasound: A case report

Transrectal contrast-enhanced ultrasound-guided transperineal core-needle biopsy versus endoscopic forceps biopsy in the diagnosis of complex rectal lesions

Background

The preoperative pathological diagnosis of rectal lesions is crucial for formulating treatment plans. For subepithelial lesions (SELs) and larger lesions with necrosis of the rectum, endoscopic forceps biopsy (EFB) cannot provide an accurate pathological diagnosis in most cases. By comparing the efficacy and safety of transrectal contrast-enhanced ultrasound-guided transperineal core-needle biopsy (TRCEUS-TP-CNB) and EFB, this study explored the value of TRCEUS-TP-CNB in the diagnosis of complex rectal lesions, such as SELs.

Methods

A retrospective, cross-sectional study was conducted with 32 consecutive patients with complex rectal lesions admitted to our hospital from May 2016 to June 2022. Clinical, ultrasound, and pathological data were collected from these patients who underwent EFB followed by TRCEUS-TP-CNB.

Results

The success rate of EFB was 21.88% (7/32) and that of TRCEUS-TP-CNB was 93.75% (30/32). No significant complications were observed for either biopsy method. Factors affecting the success rate of EFB included the lesion width (cm) (1.90±0.62 vs. 4.26±2.40, P<0.001) and lesion thickness (cm) (1.29±0.51 vs. 2.96±1.75, P<0.001). The success rate of TRCEUS-TP-CNB was not affected by these factors. In the paired study of TRCEUS-TP-CNB and EFB, the times of samples per person (1 vs. 2.14±0.90, P=0.015), number of specimens per sample (8.27±1.93 vs. 3.31±1.67, P<0.001), lesion width (cm) (3.79±2.42 vs. 1.90±0.62, P=0.001), and lesion thickness (cm) (2.64±1.75 vs. 1.29±0.51, P=0.001) were the factors affecting the difference of the sampling success rate. In the SELs, the success rate of EFB was 10% (1/10) and that of TRCEUS-TP-CNB was 100% (10/10), and the difference between the two groups was statistically significant (P=0.004).

Conclusions

TRCEUS-TP-CNB is an effective biopsy method for complex rectal lesions. The success rate of EFB is lower in the larger lesions. Compared with EFB, TRCEUS-TP-CNB required fewer times of samples be taken and obtained more specimens. For larger lesions and SELs of the rectum, TRCEUS-TP-CNB is expected to become one of the preferred biopsy methods.

Gastrointestinal stromal tumors arising in the perianal and perineal region: Two case reports and literature review

INTRODUCTION AND IMPORTANCE

Gastrointestinal stromal tumor (GIST) is rare because of its variable clinical incidence reported (from 0.4 to 2/100,000 per year) in the literature, mainly occurs primarily in the stomach and small intestine. GISTs in the perianal and perineal regions have been reported in a few pieces of literature. GIST located in the perianal and perineal regions may be misdiagnosed and missed due to atypical symptoms. We report two cases of GIST in rare sites and hope to reduce the occurrence of such events through a review of the relevant literature.

CASE DESCRIPTION

We reported two cases of GIST located in the perianal and perineal regions with different symptoms. One case underwent an emergency procedure to stop bleeding and resect the mass, and the other case was discovered during the physical examination and slowly grew in the follow-up. Following the completion of the relevant examination, the patient underwent surgical resection. Both cases were finally diagnosed as GIST by immunohistochemistry.

CLINICAL DISCUSSION AND CONCLUSION

Due to atypical clinical symptoms of perianal and perineal GIST, definitive diagnosis depends on pathology and immunohistochemistry, which can lead to misdiagnosis and missed diagnosis. Surgical resection is the preferred option for localized masses. Surgical resection of GIST located in the perianal and perineal regions requires an appropriate surgical approach based on the patients' actual condition, taking into account the protection of anal function and complete resection of the mass. Masses located in perianal and perineal region should be taken seriously by clinicians.

Value of contrast-enhanced ultrasound in deep angiomyxoma using a biplane transrectal probe: A case report

BACKGROUND

Deep angiomyxoma (DAM) is a very rare tumor type. Magnetic resonance imaging (MRI) is considered the best imaging modality for diagnosing DAM. Computed tomography (CT) is used mainly to assess the invasion range of DAM. The value of ultrasonography in the diagnosis of DAM is still controversial. Through a literature review, we summarized the current state of ultrasonic examination for DAM and reported for the first time the contrast-enhanced ultrasound (CEUS) features of DAM seen using a biplane transrectal probe.

CASE SUMMARY

A 37-year-old woman presented with a sacrococcygeal mass that had gradually increased in size over the previous 6 mo. MRI and CT examinations failed to allow a definite diagnosis to be made. Transperineal core needle biopsy (CNB) guided by transrectal ultrasound and CEUS was suggested after a multidisciplinary discussion. Grayscale ultrasound of the lesion showed a layered appearance with alternating hyperechoic and hypoechoic patterns. Transrectal CEUS showed a laminated distribution of the contrast agent that was consistent with the layered appearance of the tumor on grayscale ultrasound. We performed transperineal CNB of the enhanced area inside the tumor under transrectal CEUS guidance and finally made a definitive diagnosis of DAM through histopathology. The patient underwent laparoscopic-assisted transabdominal surgery combined with transperineal surgery for large pelvic tumor resection and pelvic floor peritoneal reconstruction. No recurrence or metastasis was found at the nine-month follow-up.

CONCLUSION

Transrectal CEUS can show the layered perfusion characteristics of the contrast agent, guiding subsequent transperineal CNB of the enhanced area within the DAM.

Needle detection using ultrasound B-mode and power Doppler analyses

BACKGROUND

Ultrasound is employed in needle interventions to visualize the anatomical structures and track the needle. Nevertheless, needle detection in ultrasound images is a difficult task, specifically at steep insertion angles.

PURPOSE

A new method is presented to enable effective needle detection using ultrasound B-mode and power Doppler analyses.

METHODS

A small buzzer is used to excite the needle and an ultrasound system is utilized to acquire B-mode and power Doppler images for the needle. The B-mode and power Doppler images are processed using Radon transform and local phase analysis to initially detect the axis of the needle. The detection of the needle axis is improved by processing the power Doppler image using alpha shape analysis to define a region of interest (ROI) that contains the needle. Also, a set of feature maps are extracted from the ROI in the B-mode image. The feature maps are processed using a machine learning classifier to construct a likelihood image that visualizes the posterior needle likelihoods of the pixels. Radon transform is applied to the likelihood image to achieve an improved needle axis detection. Additionally, the region in the B-mode image surrounding the needle axis is analyzed to identify the needle tip using a custom-made probabilistic approach. Our method was utilized to detect needles inserted in ex vivo animal tissues at shallow [20° -40°), moderate [40° -60°), and steep [60° -85°] angles.

RESULTS

Our method detected the needles with failure rates equal to 0% and mean angle, axis, and tip errors less than or equal to 0.7°, 0.6 mm, and 0.7 mm, respectively. Additionally, our method achieved favorable results compared to two recently introduced needle detection methods.

CONCLUSIONS

The results indicate the potential of applying our method to achieve effective needle detection in ultrasound images. This article is protected by copyright. All rights reserved.

Needle tract seeding and abdominal recurrence following pre-treatment biopsy of gastrointestinal stromal tumors (GIST): results of a systematic review

BACKGROUND

Gastrointestinal stromal tumors (GIST) are rare abdominal tumors. Pretreatment biopsies may be used to diagnose a GIST and enable tailored treatment. Some experts are skeptical about biopsies because they fear tumor cell seeding. The objective of this study was to determine if pretreatment biopsy is associated with increased tumor recurrence.

METHODS

We performed a systematic literature search and included studies assessing the oncological outcome of GIST patients who underwent a pre-treatment core needle biopsy or fine needle aspiration. We assessed methodological quality with the Newcastle-Ottawa-Scale for non-randomized studies. This review was registered in the PROSPERO database (CRD42021170290).

RESULTS

Three non-randomized studies and eight case reports comprising 350 patients were eligible for inclusion. No prospective study designed to answer the review question was found. One case of needle tract seeding after percutaneous core needle biopsy of GIST was reported. None of the studies reported an increased rate of abdominal recurrence in patients with pretreatment biopsy.

CONCLUSIONS

The existing evidence does not indicate a relevant risk of needle tract seeding or abdominal recurrence after pre-treatment biopsy of GIST. Biopsy can safely be done to differentiate GIST from other tumors and to select the most appropriate treatment.