Mode
Text Size
Log in / Sign up

Transrectal Ultrasound Characterization of Rectal Neuroendocrine Neoplasms Shows Feasibility in Small Retrospective CohortDoctors use ultrasound to map rare rectal tumors before surgery

AI-generated summary of the cited source, checked by automated accuracy review. How we work

Key Takeaway
Consider transrectal and contrast-enhanced ultrasound for preoperative assessment of rectal neuroendocrine neoplasms.

This retrospective analysis included 17 patients with pathologically confirmed rectal neuroendocrine neoplasms and 31 contemporaneous cases of middle- and lower-segment rectal cancer. The population comprised 8 rectal neuroendocrine tumors G1/G2 and 9 rectal neuroendocrine carcinomas G3.

Transrectal ultrasound and contrast-enhanced ultrasound assessed sonographic characteristics. All 8 rectal neuroendocrine tumors showed hypoechoic masses with clear borders. Seven cases had point-stripe blood flow signals and three cases had round-shaped lymph nodes with short diameter greater than 5 mm. Contrast-enhanced ultrasound showed inhomogeneous hyperenhancement in 2 cases and homogeneous isoenhancement in 4 cases. Rectal neuroendocrine carcinomas presented with localized irregular thickening in 8 cases and invasion in 7 cases.

The concordance rate between ultrasonographic staging and surgical pathological staging was 70.6% for all rectal neuroendocrine neoplasms. Specific rates were 87.5% for neuroendocrine tumors and 55.6% for neuroendocrine carcinomas. T stage distribution differed significantly between groups with P = 0.016. Safety data including adverse events were not reported.

Limitations include a relatively small sample size of 17 patients and the retrospective study design. The authors note this is a preliminary study needing further verification in future multi-center large-sample studies to confirm findings. Transrectal ultrasound and contrast-enhanced ultrasound are feasible for preoperative assessment and may be valuable for follow-up after endoscopic resection.

Imagine waking up with a strange lump in your lower intestine. You go to the doctor and they tell you it might be a tumor. Now imagine having a tool that shows exactly how deep that tumor goes before they cut. That is the promise of a new medical technique.

Doctors are finding a way to see these rare growths clearly. This helps them decide if a patient needs a big operation or a smaller one. The difference could mean less pain and a faster recovery for the person.

But here is the problem. Many of these tumors are hard to see on standard scans. They often look like normal tissue or simple polyps. Doctors have struggled to tell them apart without opening the patient up.

This new research changes that picture. It shows how a specific type of ultrasound can reveal the true nature of these growths. The study looked at seventeen patients who had these rare tumors confirmed by a biopsy.

A New Way to See the Problem

The doctors used a probe inside the rectum to get close-up images. They looked at eight low-grade tumors and nine high-grade ones. They compared these images to scans of common rectal cancers.

The low-grade tumors showed up as dark spots with clear edges. Seven of the eight cases showed blood flow signals. This tells the doctor the tissue is alive and growing. The high-grade tumors looked different. They appeared as irregular thickening that spread into nearby tissues.

Think of the ultrasound like a flashlight in a dark room. Standard scans are like a bright light that washes out details. This new method uses contrast dye to highlight the blood vessels inside the tumor.

The dye acts like a switch that turns on the blood flow. It helps the doctor see exactly where the tumor ends and healthy tissue begins. This is crucial because these tumors can be very small but still dangerous.

The study found that the low-grade tumors matched the scan results in most cases. The high-grade tumors were harder to stage perfectly. This difference matters because high-grade tumors grow faster and spread more quickly.

The team compared their ultrasound results to the final surgery reports. They found the scan matched the surgery in about seventy percent of all cases. For the low-grade tumors, the match was even better at eighty-seven percent.

For the high-grade tumors, the match was lower at fifty-six percent. This gap exists because these aggressive tumors invade nearby organs. The scan shows the invasion but sometimes misses the exact depth.

This doesn't mean this treatment is available yet.

The researchers were honest about this limitation. They noted that the small number of patients made the results uncertain. A larger group of people would give a clearer answer.

What This Means For Patients

If you have a rare rectal tumor, this news is hopeful. It means doctors can plan better surgeries. They can avoid cutting out healthy tissue if they know the tumor is small.

You might ask if this test is ready for you. The answer is not yet. It is still a new tool that needs more testing. Doctors will likely use it in specialized centers first.

You should talk to your doctor about your specific situation. They know your history and can tell you if this test fits your needs. Do not wait for a perfect test if your doctor suggests one now.

The study authors say more research is needed. They want to test this method in many hospitals across the country. This will help prove if it works for everyone.

The goal is to make this tool standard care. Right now it is a promising option for experts. It helps them follow patients after removing the tumor to check for return.

This research gives doctors a new map to navigate rare diseases. It brings clarity to a confusing diagnosis. Patients deserve the best tools available to them.

Study Details

Study typeCohort
EvidenceLevel 3
PublishedApr 2026
View Original Abstract ↓
ObjectiveTo evaluate the feasibility of transrectal ultrasound (TRUS) in the sonographic characterization and preoperative assessment of rectal neuroendocrine neoplasms (NENs).MethodsRetrospective analysis was performed on the transrectal ultrasound manifestations and clinical data of 17 patients with pathologically and immunohistochemically confirmed rectal NENs [8 cases of rectal neuroendocrine tumors [NETs, G1/G2] and 9 cases of rectal neuroendocrine carcinomas [NECs, G3]] between June 2020 and June 2025. These TRUS findings were compared with the ultrasound features of 31 contemporaneous cases of middle- and lower-segment rectal cancer.ResultsAll 8 rectal NETs (G1, G2) showed hypoechoic masses in the rectal mucosal and submucosal layers on TRUS, with clear borders in 8 cases, point-stripe blood flow signals in 7 cases, and round-shaped lymph nodes with a short diameter > 5 mm in 3 cases; contrast-enhanced ultrasound (CEUS) was performed in 6 cases, showing inhomogeneous hyperenhancement in 2 cases and homogeneous isoenhancement in 4 cases. Among the 9 rectal NECs (G3), 8 presented with localized irregular thickening of the rectal wall, 7 invaded perirectal tissues or organs, all lesions were hypoechoic or heteroechoic with muscularis propria infiltration, and 4 cases had enlarged local lymph nodes. Compared with rectal cancer, the distribution of T stage (T1 vs. T2–4) differed significantly (P = 0.016), whereas no significant differences were noted in gender, age, distance from the lower margin of the lesion to the intersphincteric sulcus, lesion length, lesion thickness, or N stage (all P > 0.05). The overall concordance rate between ultrasonographic staging and surgical pathological staging was 70.6% (12/17) for all rectal NENs, with 87.5% (7/8) for NETs and 55.6% (5/9) for NECs. A limitation of this retrospective feasibility study is its relatively small sample size (n = 17), which needs further verification in future multi-center large-sample studies.ConclusionsRectal NETs exhibit characteristic TRUS manifestations and require differentiation from polyps, adenocarcinomas, and inflammatory lesions. Transrectal contrast-enhanced ultrasonography (TR-CEUS), though not widely adopted, is feasible for the preoperative assessment of rectal NENs and may be valuable for follow-up after endoscopic resection to monitor recurrence.
Free Newsletter

Clinical research that matters. Delivered to your inbox.

Join thousands of clinicians and researchers. No spam, unsubscribe anytime.