Is There a Role for Intestinal Ultrasound in Polyp Detection?

ABSTRACT

We present a series of pediatric and adult cases in which intestinal ultrasound (IUS) visualized benign and malignant intestinal polyps. These cases demonstrate the potential of IUS as a rapid, noninvasive bedside modality for evaluating abdominal pain. IUS has a role in recognizing structural abnormalities and associated complications such as intraluminal masses and intussusception. Although not a diagnostic standard for polyp detection, IUS can complement endoscopy in selected cases. These findings highlight an emerging, broader application of IUS beyond inflammatory bowel disease assessment.

INTRODUCTION

Abdominal pain is a common indication for gastroenterology referral in children and adults. Intestinal polyps, although uncommon, can be associated with pain through complications such as intussusception. The diagnostic utility of gastroenterologist-performed intestinal ultrasound (IUS) for the detection of such lesions remains undefined. We describe cases highlighting the potential utility of IUS as a noninvasive evaluation of intestinal polyps. In particular, its role in real-time triage of abdominal pain outside dedicated radiology pathways remains poorly described.

CASE REPORT

Case 1

A 3-year-old girl presented with abdominal discomfort and iron deficiency anemia (hemoglobin of 6.8 g/dL, mean corpuscular volume of 62 fL, ferritin of <3 ng/mL, platelets 701 × 10⁹/L). She had no signs of gastrointestinal bleeding; however, stool hemoccult was positive twice. Despite oral iron therapy, ferritin remained low, prompting IUS to assess for bowel inflammation. IUS in all cases in this series was performed by an International Bowel Ultrasound Group–trained gastroenterologist in the outpatient setting. IUS identified an intraluminal mass in the right upper quadrant that was heterogeneous in echotexture with significant vascularity on color doppler flow (Figure 1, panel A). This was accompanied by associated intussusception, as revealed by the “onion peel” (or “doughnut”) sign on axial view and “hay-fork” (or “pseudo-kidney”) sign on longitudinal view (Figure 2, panels A and B). The remainder of the bowel appeared normal. Colonoscopy revealed a 3-centimeter pedunculated polyp at the hepatic flexure, which was removed with hot snare polypectomy. Histopathology confirmed a hamartomatous (juvenile) polyp (Figure 1, panel B).

Figure 1.

IUS and endoscopic correlates of intestinal polyps. (A) IUS appearance of a 2.8-cm heterogenous, vascular hamartomatous polyp in the right upper quadrant with Doppler applied at 6.5 cm/s in case 1. (B) En face view of the hamartomatous polyp identified as the lead point for intussusception in case 1. (C) With color Doppler, mild hyperemia and submucosal prominence in the cecum from case 3. (D) Cecal juvenile lobulated polyp with visible stalk, case 3. (E) IUS appearance of the intraluminal mass at the hepatic flexure with multiple hypoechoic components in case 4. (F) Subcentimeter juvenile polyps correlating with IUS findings at the hepatic flexure in case 4. IUS, intestinal ultrasound.

Figure 2.

Intestinal ultrasound findings in intussusception. (A) Longitudinal view showing the “hay-fork” or “pseudo-kidney” appearance consistent with intussusception in case 1. (B) Concentric “onion peel” of intussuscepted bowel in case 1. (C) Example of a polyp in a pediatric patient, as a possible lead point for intussusception. (D) Longitudinal view of the intussusception showing the “hay-fork” or “pseudo-kidney” appearance, involving the distal ileum in case 2. (E) Axial view showing the concentric “onion peel” or “donut sign” of intussuscepted bowel in case 2. (F) Hypoechoic, intraluminal spindle cell tumor (2.3 × 2.9 × 3.4 cm) identified at the lead point in case 2. Images were acquired using a Samsung RS85 (case 1) and RS80 (case 2) ultrasound systems with a 2–14 MHz convex probe.

Case 2

A 66-year-old man presented with chronic intermittent abdominal pain and diarrhea. He had a history of a recent diagnosis of ileal Crohn's disease on ileocolonoscopy, as well as multiple comorbidities including mechanical aortic valve, complete heart block with pacemaker, Takayasu arteritis, and hepatitis C cirrhosis. He underwent IUS, which showed an area of thickened bowel 4 cm proximal to the ileocecal valve with “onion peel” appearance consistent with intussusception (Figure 2, panel E). Mild increased color Doppler signal was seen in this segment. No upstream dilation was seen, and the remainder of the small bowel and colon was normal. These findings were confirmed with CT imaging findings. In both imaging instances, no associated lesions were seen, and given the history of ileal Crohn's disease, he was empirically treated with corticosteroids to assess for symptomatic improvement, as he was deemed a high-risk candidate for double-balloon enteroscopy. Shortly after his initial imaging, he was admitted with a partial small bowel obstruction. Repeat IUS revealed a 2.3 × 2.9 × 3.4-centimeter hypoechoic, vascular intraluminal mass at the site of intussusception (Figure 2, panel F). Segmental resection and histopathology confirmed a 3.5-centimeter low-grade submucosal spindle cell neoplasm with negative margins and lymph nodes. Adjacent ileum showed active ileitis in keeping with his known ileal Crohn's disease. Symptoms resolved postoperatively, through ileal activity persisted on follow-up imaging.

Case 3

A 6-year-old girl presented with 3 months of fatigue and generalized abdominal pain. She had iron deficiency anemia (hemoglobin 7.7 g/dL, mean corpuscular volume 64 fL, ferritin of 3 ng/mL) and 3 positive fecal occult blood tests, without visible bleeding. Stool calprotectin was elevated (1,810 mcg/g), and other laboratory findings were normal. IUS showed segmental bowel wall thickening (maximal bowel wall thickness 2.8 millimeters) with submucosal prominence and patchy hyperemia from the mid-transverse colon to the hepatic flexure, accompanied by reactive mesenteric lymphadenopathy. The cecum demonstrated submucosal prominence and mild hyperemia, whereas the ileocecal valve and terminal ileum were normal (Figure 1, panel C). Ileocolonoscopy demonstrated multiple pedunculated polyps throughout the colon including rectal, splenic flexure, transverse, hepatic flexure, and the cecal locations (totaling 8 polyps). These were removed with cold snare polypectomy and histopathology confirmed juvenile polyps (Figure 1, panel D), and genetics excluded polyposis syndromes. Symptoms and anemia resolved after polypectomy.

Case 4

A 5-year-old girl presented with intermittent abdominal pain and hematochezia for 1 year. Growth and weight gain were normal. Stool testing was positive for occult blood, and fecal calprotectin was elevated (867 ug/g). Bloodwork was normal. IUS revealed a normal sigmoid, descending and transverse colon except at the hepatic flexure, where a large intraluminal mass with multiple hypoechoic components was visualized (Figure 1, panel E). A second intraluminal mass with a stalk-like branching pattern was visualized in the cecum. The terminal ileum appeared normal. The ileocolonoscopy demonstrated 2 subcentimeter polyps at the hepatic flexure (Figure 1, panel F) and a larger polypoid mass in the cecum, all removed with snare polypectomy. Histopathology confirmed juvenile polyps. The patient's abdominal pain and hematochezia resolved after polypectomy.

DISCUSSION

The diagnostic role of gastroenterologist-performed IUS in detecting and characterizing intestinal polyps has not been well described. This case series illustrates its potential utility as a noninvasive imaging modality for identifying intestinal polyps in both pediatric and adult populations. Studies of transabdominal ultrasound for polyp detection are limited and heterogenous. Detection is most reliable for lesions >1 centimeter in size, whereas small or sessile polyps remain challenging.¹ Of note, IUS is not recommended for the detection of intestinal polyps. Although not utilized in the cases presented in this series, colon preparation or glycerin enemas may enhance visualization but require sedation.^2–4 Graded compression sonography has been shown to enhance polyp detection without the need for colon preparation.⁵ Polyps in the rectum and sigmoid are less readily visualized due to pelvic depth.⁶ In adults, ultrasound can identify polyps >1 centimeter in size with high specificity (99.4%) but modest sensitivity 28.6%.^7,8

In this case series, IUS identified polyps ranging from subcentimeter to 3.5 centimeter. Sonographic features were variable. Based on our cases, features on IUS that may suggest a pedunculated polyp are evidence of a hypoechoic lesion with hyperemia and increased vascularity on color Doppler along the vascular stalk. In other lesions, there was mildly thickened bowel wall that correlated with the location of small polyps on colonoscopy. IUS also identified intussusception, with classically described “onion-peel” and “hay-fork” signs.^9,10

Gastroenterologist-performed IUS offers real-time, radiation-free and noninvasive refinement of the differential diagnosis and may complement endoscopic and cross-sectional imaging, particularly in pediatric or medically complex patients. Our case series demonstrates a proof of principle that IUS in the point-of-care setting can readily identify complications of intraluminal lesions and help determine the urgency of next steps, from endoscopy to surgical referral. As IUS adoption expands in gastroenterology, defining its specificity and sensitivity, as well as limitations in polyp and intraluminal mass detection, will help guide appropriate clinic integration.

DISCLOSURES

Author contributions: M. Dolinger, J. St-Pierre, and A. Kellar provided the case data and patient consents. S. Muralidharan compiled the case data and drafted the manuscript draft. All authors provided further revisions and approved the final version for submission. All authors meet the ICMJE criteria for authorship. A. Kellar is the article guarantor.

Disclosures: S.M., A.K., and MD: None to report. J.S.-P. has served as a speaker for Takeda, as well as received consultation fees from Abbvie, Eli Lilly, Pfizer, and Pendopharm.

Financial disclosure: None to report.

Informed consent was obtained for this case report.

ABBREVIATIONS:

CT

computed tomography

IUS

intestinal ultrasound

RUQ

right upper quadrant