Endoscopic features with linked-color imaging of non–Helicobacter pylori Helicobacter-associated gastritis: a case study

Abstract

Background and Aims

The endoscopic findings of non–Helicobacter pylori Helicobacter (NHPH) are not widely known. Linked-color imaging (LCI) has emerged as a new system for image-enhanced endoscopy (IEE) that enhances color tone and improves visibility. The aim of this case study was to assess how endoscopic findings of NHPH are enhanced with LCI.

Methods

We report the case of a 72-year-old woman in whom an NHPH species was found during EGD using LCI.

Results

The EGD did not reveal any endoscopic findings of diffuse redness, patchy redness, or atrophy. However, erosions, nonuniform redness, and crack-like mucosa were seen in the antrum, as well as LCI-enhanced endoscopic findings. In addition, nodular gastritis and a white marbled appearance were also observed in the antrum. LCI and blue-laser imaging enhanced the endoscopic findings. Floating bacterial bodies with a fine coil-like shape and diameter longer than that of H pylori were pathologically observed in the mucus, suggesting NHPH. A polymerase chain reaction test led to a diagnosis of Helicobacter suis.

Conclusions

Our case demonstrates that IEE is useful in diagnosing NHPH. The detection of NHPH using IEE enabled us to contribute to an improved diagnosis of NHPH.

Video

Video 1

Nodular gastritis, a white marbled appearance, and crack-like mucosa were observed in the antrum. Linked color and blue laser imaging emphasized endoscopic findings.

Introduction

Non–Helicobacter pylori Helicobacter (NHPH) species have been reported in recent years. However, compared to H pylori (HP), the endoscopic findings of NHPH are not widely known, and concerns exist that some cases may be missed when diagnosed endoscopically. Linked-color imaging (LCI) has emerged as a new system for image-enhanced endoscopy (IEE) that enhances color tone and improves visibility. Here, we present the first report of a case of a patient in whom NHPH was found using LCI.

Case Presentation

A 72-year-old woman underwent an EGD during a health examination. The EGD did not reveal endoscopic findings of HP infection, such as diffuse redness, patchy redness, enlarged folds, and atrophy, and showed a regular arrangement of collecting venules (RAC) in the body of the stomach (Fig. 1). Erosions, nonuniform redness, and a crack-like mucosa were seen in the antrum; LCI enhanced the endoscopic findings (Fig. 2). Nodular gastritis and a white marbled appearance were also observed in the antrum; LCI and blue-laser imaging (BLI) also enhanced the endoscopic findings (Fig. 3; Video 1, available online at www.videogie.org). In comparison, RAC was not observed in the lesser curvature of the gastric angle. Serum anti-HP immunoglobulin G was negative (<3.0 mg/mL). A biopsy specimen was taken from the antrum and, according to pathologic findings, the atrophy found was very mild. Additionally, an inflammatory cell infiltration into the lamina propria was mild and consisted of lymphocytes and plasma cells. Floating bacterial bodies, with a fine coil-like shape and diameter longer than that of HP, were observed in the mucus suggesting NHPH. HP was not observed (Fig. 4). A polymerase chain reaction test was performed using a previously described method,¹ and a diagnosis of Helicobacter suis was made. Because this patient was asymptomatic and older, eradication therapy was undesirable, and she was subsequently followed up.

Figure 1.

Endoscopic findings in the body of the stomach using white-light imaging. A, EGD revealed no diffuse redness, patchy redness, or enlarged folds. B, EGD revealed no atrophy. The regular arrangement of collecting venules was observed in the body.

Figure 2.

Endoscopic findings in the antrum and gastric angle using white-light or linked-color imaging. A, White-light imaging (WLI). Erosions and nonuniform redness were seen in the antrum. B, Linked-color imaging (LCI). Erosions and nonuniform redness were emphasized with LCI. C, WLI. A crack-like mucosa was observed in the lesser curvature of the angle. The regular arrangement of collecting venules was not seen. D, LCI. LCI allowed crack-like mucosa to become more defined. E, Close-up observations with WLI. Crack-like mucosa was observed in the antrum. F, Close-up observations with LCI. Crack-like mucosa was enhanced with LCI.

Figure 3.

Endoscopic findings in the antrum using white-light, linked-color, or blue-laser imaging. A, White-light imaging. Nodular gastritis and a white marbled appearance were observed in the antrum. B, Linked-color imaging. Nodular gastritis and a white marbled appearance were emphasized with linked-color imaging. C, Blue-laser imaging. Nodular gastritis and a white marbled appearance were emphasized with blue-laser imaging.

Figure 4.

Pathologic findings of a biopsy specimen. A, A pathologic section revealed atrophy that was very mild (H&E staining, loupe image). B, Inflammatory cell infiltration into the stroma was mild and consisted of lymphocytes and plasma cells. The red-bordered inset of the loupe image (H&E, orig. mag. ×100). C, Floating bacterial bodies were observed in the mucus. These had a fine coil-like shape with a diameter that was larger than that of Helicobacter pylori, suggesting non–H pylori Helicobacter (arrows). The yellow-bordered inset of the loupe image (Giemsa stain).

NHPH is considered to be one of the causes of mucosa-associated lymphoid tissue lymphoma or gastric cancer.^2,3 The incidence of NHPH in the population ranges from 0.1% to 6.2%4, 5, 6, 7, 8, 9; however, the number of reports will likely increase as the HP infection rate in the population declines and NHPH becomes more widely known.

The pathologic characteristics of NHPH are that it is a relatively long and wide bacterium compared with HP, and it has a tightly coiled spiral shape. It is found in the mucus gel and/or on the surface mucus of gastric epithelial cells but does not adhere to them. Inflammatory cell infiltration into the lamina propria is mild.^5,10,11

The endoscopic diagnosis of NHPH is based on characteristic findings, such as a white marbled appearance,¹² nodular gastritis, and crack-like mucosa,¹³ which were emphasized in this case by LCI and BLI. Nodular gastritis is an endoscopic finding of HP infection in young patients.¹⁴ However, when this is observed in an older person without HP, as in this case, this may lead to a suspicion of NHPH.

LCI is an IEE that is characterized by an improvement in the visibility of gastric inflammation. This is because LCI uses a bright light with a color close to that of normal light and because image processing is performed to improve color separation. In 2020, the LCI-FIND trial comparing white-light imaging (WLI) showed that screening endoscopy using LCI is useful for detecting upper GI tumors in cases with a high risk of developing upper GI tumors.¹⁵ In diagnosing HP-infected gastritis, LCI emphasized the diffuse redness of a current HP infection. The accuracy of diagnosing HP infection with LCI was 85.8%, making it more useful than normal light.¹⁶ In a multicenter prospective study, the accuracy of diagnosing HP gastritis was significantly higher with LCI than with normal light.¹⁷ Figure 5 shows representative endoscopic images of an HP-positive case using WLI and LCI, respectively. The background mucosa shows inflammatory findings such as diffuse redness and enlarged folds. The diffuse redness was emphasized as a deep reddish color with LCI compared to WLI.

Figure 5.

Endoscopic findings in the body of the stomach of a patient with Helicobacter pylori via white-light and linked-color imaging. A, White-light imaging. Diffuse redness and enlarged folds were observed in the body of the stomach. B, Linked-color imaging. Diffuse redness was emphasized in a deep reddish color with linked-color imaging.

Based on the Kyoto classification of gastritis, we previously described how the visibility of each endoscopic finding was improved by LCI/BLI-bright compared to WLI.¹⁸ LCI improved the visibility of findings such as diffuse redness, spotty redness, map-like redness, patchy redness, red streaks, intestinal metaplasia, and an atrophic border by emphasizing the color tone. BLI-bright improved the visibility of intestinal metaplasia and was considered effective for white-colored lesions. In this case, we found erosions—areas of nonuniform redness—in the antrum using WLI, and we therefore performed detailed observations using LCI and BLI. LCI enhanced the findings, such as a white marbled appearance, nodular gastritis, and crack-like mucosa, and BLI was considered useful for nodular gastritis, which is white in color. Therefore, LCI or BLI are useful for diagnosing HP infection and assessing the risk of gastric cancer but may also be useful for diagnosing NHPH. Currently, NHPH may not be properly diagnosed by endoscopy. The use of IEE may enhance findings and raise the suspicion of NHPH. If NHPH is suspected, a definitive diagnosis can be obtained more frequently by biopsy. An adjunctive diagnosis using IEE may contribute to the improved diagnosis of NHPH.

Disclosure

Drs Takeda, Asaoka, and Nagahara were supported by a joint clinical research grant from Fujifilm Co, Ltd (2018-028). All other authors disclosed no financial relationships relevant to this publication.

Supplementary data

Video 1

Nodular gastritis, a white marbled appearance, and crack-like mucosa were observed in the antrum. Linked color and blue laser imaging emphasized endoscopic findings.