Diagnostic challenge of gastritis cystica profunda with secondary abscess formation: A case report

Abstract

BACKGROUND

Gastritis cystica profunda (GCP) is a rare submucosal gastric lesion characterized by the extension of cystically dilated gastric mucosal glands into or below the muscularis mucosa, often due to various underlying causes. Typically, asymptomatic or associated with mild symptoms, GCP is most commonly discovered incidentally during surgery or endoscopy. To the best of our knowledge, this is the first documented case of GCP accompanied by acute inflammation and abscess formation.

CASE SUMMARY

A 37-year-old woman presented with upper abdominal pain. Laboratory tests showed elevated inflammatory markers and carbohydrate antigen 19-9 levels. Gastroscopy revealed a submucosal bulge. Based on enhanced computed tomography findings, an ectopic pancreas with cyst was suspected. Clinically, we decided to perform distal gastrectomy. Postoperative pathology confirmed that the patient had GCP complicated by acute inflammation and abscess formation. The patient had an uneventful postoperative recovery.

CONCLUSION

This case provides information on new complications of GCP and emphasizes the diagnostic value of enhanced computed tomography.

Key Words: Gastritis cystica profunda; Ectopic pancreas; Submucosal tumor; Gastric abscess; Endoscopic resection; Case report

Core Tip: Gastritis cystica profunda (GCP) is a rare submucosal lesion of the stomach, and its etiology and pathogenesis remain unclear. It is generally considered benign, and no standardized treatment protocol currently exists. We report a case of GCP complicated by acute inflammation and abscess formation, successfully treated with partial gastrectomy. This case highlights a previously unreported complication of GCP and underscores the diagnostic utility of enhanced computed tomography for GCP.

INTRODUCTION

Gastritis cystica profunda (GCP) is a rare condition first identified and named by Franzin and Novelli[1] in 1981, because of its histological resemblance to colitis cystica profunda. GCP is characterized by pathological cystic dilation of gastric glands located at or below the muscularis mucosa. These glands are typically regular and intact and may be associated with connective tissue proliferation and inflammatory cell infiltration[2]. GCP primarily affects middle-aged and elderly men, most often occurring in the upper third of the stomach. The etiology and pathogenesis remain unclear. GCP accounts for < 1% of gastric submucosal lesions, typically detected incidentally during endoscopic examinations or postoperative pathological analysis, and its incidence may therefore be underestimated. Clinical manifestations can be asymptomatic or present with nonspecific gastrointestinal symptoms, such as abdominal pain, abdominal discomfort, gastrointestinal bleeding, nausea, vomiting, anorexia, and weight loss[3-6]. In the present case, the patient presented with abdominal pain. Notably, postoperative pathology confirmed concurrent acute inflammation and abscess formation. Abscess formation has not been previously reported in GCP, thereby expanding the recognized spectrum of potential complications associated with this disease.

Due to the rare occurrence and nonspecific manifestations of GCP, diagnosis can be challenging. Endoscopic ultrasonography (EUS) and computed tomography (CT) may aid in the differential diagnosis, but these methods are usually insufficient for definitive diagnosis. At present, histopathological examination is considered the gold standard for diagnosis remains pathological examination. Here, we present a rare case of GCP accompanied by acute inflammation and abscess formation, which was preoperatively misdiagnosed as an ectopic pancreas with cysts on CT. We retrospectively analyzed the clinical and pathological data, as well as the gastroscopic and CT findings, to provide insights that may enhance diagnostic accuracy and treatment strategies for this uncommon condition.

CASE PRESENTATION

Chief complaints

A 37-year-old woman presented with upper abdominal pain, described as intermittent and distending.

History of present illness

The pain had started after the patient self-administered one tablet of loxoprofen for back pain 2 days prior to admission.

History of past illness

In 2018, the patient had been informed during an examination at another hospital of a gastric mass that was considered a stromal tumor by endoscopic ultrasound. The patient was lost to follow-up until symptoms recurred in 2025.

Personal and family history

In 2016, the patient underwent a unilateral salpingectomy due to an ectopic pregnancy. She reported no family history of malignant tumors.

Physical examination

Tenderness was noted in the upper abdomen, without rebound tenderness. The abdomen was soft and flat, and no palpable mass was detected.

Laboratory examinations

Laboratory tests upon presentation revealed the following abnormalities: White blood cell count of 15.5 × 10⁹/L [reference range: (3.5-9.5) × 10⁹/L], neutrophil count of 13.6 × 10⁹/L [reference range: (1.8-6.3) × 10⁹/L], and C-reactive protein (wide range) level of 15.6 mg/L (reference range: 0.2-4 mg/L). Additionally, the tumor marker carbohydrate antigen [carbohydrate antigen 19-9 (CA19-9)] level was elevated at 157.54 U/mL (reference range: < 37 U/mL). All other laboratory parameters were within normal limits.

Imaging examinations

White-light gastroscopy revealed congestion and edema of the gastric antral mucosa, with a submucosal bulge approximately 4.0 cm in diameter on the anterior wall (Figure 1A and B). Optical electronic chromoendoscopy demonstrated the micro surface and microvascular structures of the lesion (Figure 1C). The lesion exhibited a soft texture when pressure was applied using a pair of biopsy forceps (Figure 1D). A plain CT scan revealed considerable thickening of the anterior wall of the gastric body and antrum, with the thickest area measuring approximately 3.2 cm (Figure 2A). The lesion had a density lower than that of muscle, with an average CT value of approximately 35 Hounsfield unit. The corresponding gastric cavity was narrowed; however, the gastric wall was soft rather than rigid. Mild exudation was noted around the gastric antrum, along with several small lymph nodes. An enhanced CT scan revealed a smooth, continuous mucosal line with marked enhancement (Figure 2B), patchy submucosal edema, and a multicystic submucosal mass measuring approximately 3.9 cm × 2.5 cm × 2.6 cm on the anterior wall of the gastric antrum (Figure 2C and D). The cyst walls showed marked enhancement. Based on these findings, the CT diagnosis suggested an ectopic pancreas with cysts.

Figure 1 Gastroscopy showing a submucosal bulge in the gastric antrum. A: White-light gastroscopy revealed congestion and edema of the gastric antral mucosa, with a 4-cm submucosal bulge on the anterior wall; B: Close-up view of the lesion; C: Optical electronic chromoendoscopy demonstrated the micro-surface and microvascular structures of the lesion; D: Application of pressure with a pair of biopsy forceps confirmed a soft texture.

Figure 2 Contrast-enhanced computed tomography images. A: Plain computed tomography showed significant thickening of the anterior wall of the gastric body and antrum with low-density areas; B: The mucosal line appeared continuous, with the lesion in the submucosa surrounded by patchy edema; C: In the arterial phase, multiple submucosal cystic lesions of varying sizes were visible in the anterior wall of the gastric antrum, with ring-like enhancement of the cyst walls; D: In the venous phase, the cyst walls exhibited persistent enhancement; in contrast, the cyst contents remained non-enhancing.

FINAL DIAGNOSIS

Microscopically, acute inflammation with abscess formation was observed in the gastric submucosa, with the abscess cavity focally lined by gastric mucosal tissue (Figure 3). This finding was attributed to entrapped and dilated glands with abscess formation. The final pathological diagnosis was GCP.

Figure 3 Routine pathology and immunohistochemistry. A: Hematoxylin and eosin staining, 10 ×. Histology revealed multiple cystic spaces in the submucosa, with cyst walls lined by columnar epithelium, accompanied by neutrophil infiltration and abscess formation; B: Immunostaining, 10 ×. Immunohistochemistry showed a Ki-67 index of approximately 1%.

TREATMENT

Clinically, the elevated CA19-9 level raised concerns about the possibility of a tumor. After discussing the risks, the patient consented to a laparoscopic partial gastrectomy. During surgery, intraoperative exploration revealed a small amount of ascitic fluid and adhesions in the upper abdomen. No external invasion was observed on the gastric serosal surface. A distal gastrectomy was performed successfully, and the patient experienced an uneventful postoperative recovery.

OUTCOME AND FOLLOW-UP

The patient was discharged from the hospital 12 days after the operation. A telephone follow-up was conducted 6 months later, and it was found that the patient had a good recovery.

DISCUSSION

GCP is a rare inflammatory gastric lesion most commonly observed in middle-aged and older men. It predominantly occurs in the gastric body, followed by the cardia, fundus, and antrum[7,8]. Its etiology is generally considered a secondary response to repeated epithelial erosion and regeneration, typically occurring in the context of chronic gastritis. Studies suggest that chronic inflammation, mucosal ischemia, bile reflux, and prior gastric surgery can disrupt the muscularis mucosae, allowing mucosal epithelium to migrate into the submucosa or muscularis propria[1,9,10]. This migration leads to cystic dilation of the glands and subsequent submucosal cyst formation. Cho et al[11] proposed that most heterotopic submucosal glands (HSG) are proliferative lesions caused by oncogenic gene mutations, rather than the commonly assumed inflammatory changes. They analyzed 63 cases of HSG using targeted next-generation sequencing and immunohistochemistry and found that over 50% of the lesions carried activating mutations in the KRAS gene. This finding suggests that genetic alterations may contribute to the development of HSG.

GCP is often asymptomatic but can present with non-specific gastrointestinal symptoms, including abdominal pain, bloating, acid reflux, and vomiting. Severe cases may lead to complications, such as hematemesis, melena, and pyloric obstruction[12,13]. Laboratory findings are typically unremarkable; however, our patient presented with epigastric pain accompanied by acute inflammation, which resulted in elevated white blood cell count, neutrophil count, and C-reactive protein level. Medication may have triggered concurrent acute inflammation. Generally, GCP is not accompanied by elevated tumor markers. However, when it coexists with neoplastic lesions, an increase can occur. In this patient, the lesion was an isolated GCP. Elevated CA19-9 may reflect cyst fluid secretion or systemic inflammation[14].

Gastroscopy typically reveals GCP as a submucosal bulge. However, mucosal-layer biopsies are insufficient for a definitive diagnosis. EUS can reveal submucosal lesions of the digestive tract, observe the layered structure of the gastric wall, and determine the origin of the lesions and their relationship with surrounding tissues, thus playing a crucial role in the diagnosis of GCP. The echotexture of GCP can be homogeneous or heterogeneous, and the echo pattern is classified as hypoechoic, hyperechoic, or mixed echo, which can be summarized into three forms: Heterogeneous echo with mucosal thickening, anechoic cystic cavity in the submucosa, and hypoechoic with small cysts[15]. The typical manifestation is an irregular hypoechoic area originating from the gastric mucosa and gradually extending into the submucosa and even the muscularis propria. However, these findings lack specificity, and EUS localization can be imprecise. Additionally, EUS is an invasive examination that requires anesthesia, which may reduce the willingness of some patients to undergo the examination.

EUS better evaluates layer-by-layer involvement, CT’s advantage lies in assessing adjacent invasion. GCP typically appears on CT as a submucosal cystic or cystic-solid mass with gastric wall thickening and small cysts[16,17]. Key features include cystic components corresponding to glandular dilation, progressive enhancement, and peripheral ring-like enhancement[18]. In some cases, enhanced CT shows a “sandwich-like enhancement” (the surface cyst wall of the lesion is enhanced, the central cystic area is not enhanced, and the underlying muscular layer is enhanced) or a “honeycomb sign” (multiple small cystic enhancements). When the glandular dilation is not obvious or the dilated glands are accompanied by bleeding, it can present as a soft tissue mass with heterogeneous enhancement. In this case, CT revealed a multicystic submucosal mass in the gastric antrum with ring-like enhancement of the cyst walls. Although CT accurately localized the lesion, the preoperative diagnosis was incorrect, likely due to insufficient awareness of GCP. Inflammatory edema of the gastric body and antrum wall was observed, and the lesion was misdiagnosed as an ectopic pancreas with cysts.

The incidence of gastric ectopic pancreas in gastrectomy cases is approximately 0.9%, most commonly occurring in the gastric antrum[19]. Typical CT findings include a submucosal flat solid mass with a long diameter/short diameter ratio greater than 1.4, an endoluminal growth pattern, ill-defined borders, and significantly enhanced overlying mucosa[20]. The lobulation sign, duct sign, and central umbilication sign are considered characteristic, but are only observed in a minority of cases. When the ectopic pancreas undergoes cystic changes, it should be differentiated from GCP, as present in Table 1. Ectopic pancreas with cysts is a rare condition attributed to pseudocyst formation, abnormal ductal dilation, or intraductal papillary mucinous neoplasms, mucinous cystadenoma[21-23]. The cyst wall of ectopic pancreas lesions typically exhibits enhancement patterns consistent with that of pancreatic parenchyma. Careful evaluation of these patterns may aid differentiation. Magnetic resonance imaging has unique advantages in the diagnosis of ectopic pancreas. The acinus is rich in protein and glycogen, and it shows a characteristically high signal in T1 weighted images[24]. T2 weighted images and magnetic resonance cholangiopancreatography are helpful in identifying residual ducts.

Table 1 Comparison of gastritis cystica profunda and ectopic pancreas.

	Gastritis cystica profunda	Ectopic pancreas
Age	Elderly	Middle-aged
Location	Gastric body	Antrum
Morphology	Sphere, hemisphere, diffuse	Flat ovoid, long diameter/short diameter > 1.4
Endoscope	Soft texture, submucosal bulge, polypoid lesion, hypertrophic fold	Toughness, submucosal bulge, umbilicated depression on the surface
Endoscopic ultrasonography	Anechoic, mixed echoic with thickened mucosa, hypoechoic with microcysts	Heterogeneous hypoechoic, mixed cystic and solid, anechoic ductal structure
Computed tomography	Cystic change in submucosa, progression enhancement, peripheral rim-like enhancement	Endoluminal growth, lobulation sign, ill-defined border, prominent enhancement of overlying mucosa

GCP is considered a benign lesion; however, some cases may exhibit dysplasia or malignant transformation. Increasingly, studies suspect precancerous lesions[11,25,26]. Whether GCP progresses to gastric cancer by itself or is influenced by common pathogenic factors remains inconclusive. Itami et al[10] identified GCP as a paracancerous lesion in gastric cancer, because no cancer was found to have originated from HSG. Cho et al[11] found that contrary to the frequent presence of KRAS and GNAS gene mutations in HSG, the atypical hyperplasia and adenocarcinoma do not carry these mutations. Therefore, it is believed that HSG has a limited role in the occurrence of gastric cancer development. However, in their study, 5 out of 63 HSG lesions exhibited dysplastic components, suggesting that although rare, HSGs have the potential to serve as premalignant lesions. In fact, several reports have described cases of gastric adenocarcinoma arising from HSG[25,26]. In this case, the patient had a 7-year history of GCP; however, postoperative pathology revealed no dysplasia or malignancy, further supporting the benign nature of GCP. This is consistent with the immunohistochemical results. Ki-67, a nuclear protein present in the nuclei of proliferating cells, is expressed during the cell proliferation phase and used to evaluate cell proliferation. The Ki-67 index in this GCP specimen was approximately 1%, indicating low proliferative activity of the lesion. The low Ki-67 index (1%) aligns with the absence of KRAS mutations in this case. We believe that although the overall incidence of dysplasia and carcinogenesis in HSG lesions is low, they still have malignant potential. When GCP is suspected, close endoscopic follow-up or further histopathological confirmation is required.

At present, there are no clear guidelines and conventions for the treatment of GCP. Because of the uncertainty of preoperative diagnosis, treatment options for GCP include endoscopic and surgical approaches. When the lesion measures less than 3.0 cm, endoscopic submucosal dissection (ESD) is the preferred treatment approach[14,27]. ESD achieves an enbloc resection rate of over 90% for GCP lesions, with rare complications such as bleeding or perforation[28]. Compared to traditional surgery, ESD offers several advantages: High safety, minimal invasiveness, lower cost, faster recovery, and most importantly, preservation of gastric function with minimal trauma. For lesions measuring 3.0-5.0 cm, laparoscopic surgery is a viable option. Partial gastrectomy can relieve symptoms and provide a curative outcome. However, when the lesion exceeds 5.0 cm, open surgery is generally required due to poor visibility during laparoscopy[27]. In the present case, considering the lesion’s large size, which might prevent complete specimen extraction from the cardia after ESD, laparoscopic partial gastrectomy was chosen with the patient’s informed consent. The patient had an uneventful postoperative recovery.

CONCLUSION

This case highlights abscess formation as a novel GCP complication, necessitating pathological confirmation despite advanced imaging. Although the malignant potential of GCP remains uncertain, active treatment is recommended, with ESD considered a safe and effective therapeutic option.