INTRODUCTION

Gastric adenomyoma is a rare benign pathology characterized by ducts and glands surrounded by smooth muscle stroma^1-5. The ages of presentation are variable, presenting from neonates to the elderly². 52 cases have been described in the literature up to 2017^1,4. The most frequent age of presentation is between the fourth and sixth decades of life^1,4without gender predilection¹and may be associated with annular pancreas, Gardner syndrome with duodenal adenomas and gastric duplication¹. The clinical presentation is variable, and may include nausea, vomiting, epigastric pain, even hematemesis, anemia and melena^1,3,4. Despite being considered a benign disease, cases of malignant transformation have been described in up to 2%⁴. The importance of taking this pathology into account lies above all when the endoscopic findings are inconclusive in the presence of pyloric syndrome that does not show malignant disease or other types of obvious obstructive lesions.

CLINICAL CASE

A 52-year-old male, natural from Iquitos, with no relevant history, goes to the emergency room reporting 3 days of epigastric pain, nausea, vomiting and the inability to eliminate flatus for 2 days; also loses weight of 7kg in 1 month and oral intolerance to solids and liquids; also, increased appetite. Examination shows marked distension of the upper abdomen with tympanism, without peritoneal reaction; A simple abdominal X-ray was performed, showing great dilatation of the gastric chamber with no signs of lower intestinal obstruction or air-fluid levels. It is concluded that the patient presents emesis due to a pyloric syndrome to rule out an infiltrative lesion; hospitalization is indicated to complete studies.

The total abdominal tomography with intravenous contrast evidenced: stomach with distention and food content inside, impresses conditioned by an obstructive process located at the pyloric level that is thickened up to 16mm with diffuse mucosal enhancement of probable inflammatory cause, the adjacent fat shows diffuse striation ; concluding mural thickening at the level of the pyloric region with diffuse mucosal enhancement conditioning gastric obstructive process, consider high suspicion of inflammatory process, the possibility of neoplastic infiltrative process is not discard.

An upper gastrointestinal endoscopy was performed where a linear ulcer with regular edges and a fibrinous bed was described at the level of the gastric angle, which were biopsied, as well as deformed antrum due to healing of the lesser curvature ulcer, pylorus occluded due to healing of the lesser curvature ulcer. Duodenal bulb and second duodenal portion not observed; gastric ulcer was concluded that deforms and occludes pylorus without signs of active bleeding. The pathological anatomy described severe active plasmacytic chronic gastritis with edema and fibrosis of the lamina propria, regenerative epithelium with mild dysplasia, necrotic ulcer fundus with shadow cells.

Preoperative studies describe: Leukocytes 8.03x103/uL, Hemoglobin 12.1g/dL, Platelets 320x103/uL, blood group O positive, Albumin 4.1g/dL, Creatinine 0.69mg/dL, Glucose 94mg/dL, Urea 41.2mg/dL.

After the endoscopic studies and the pathological anatomy reports do not conclude the etiology of the pyloric syndrome, it is decided to perform a Radical Distal Gastrectomy with D2 Lymphadenectomy with reconstruction by Y Roux Gastrojejunostomy due to a pre-pyloric gastric inflammatory process that conditions partial obstruction of the pylorus, where the possibility of a neoplastic infiltrative process is not ruled out. The findings showed a pre-pyloric gastric tumor with lesser curvature of 4x3cm in diameter, hard that occludes and compresses the pylorus, with serosal retraction of the posterior gastric wall that conditions gastric chamber dilatation. No liver or peritoneal lesions or free fluid. After the surgical procedure, the patient evolved favorably and was discharged on the eleventh postoperative day with good oral tolerance.

The pathological anatomy report of the operative piece described: Gastric adenomyoma with multiple ulcerative lesion, fibrosis and serosal retraction with hypertrophic arterial vessels that reach the submucosa (Figure 1) Peri-ulcerative regenerative epithelium and granulation tissue with isolated giant cells of the foreign body type . Chronic follicular gastritis with follicular mantle hyperplasia, free surgical margins - free omentum, free perigastric lymph nodes 0/26 with adenitis and lymphatic congestion.

Figure 1: Microscopy, Hematoxylin Eosin. Groups of glands surrounded by bundles of smooth muscle. a(x10) b(x40) 

DISCUSSION

Gastric adenomyoma is a rare benign lesion composed of ducts and glands surrounded by smooth muscle stroma^1-5. Also known as myoglandular hamartoma, adenomyomatous hamartoma or myoepithelial hamartoma^2,3,5. It is usually found in the antrum and pylorus and, when the adenomyoma is extragastric, it is located in the duodenum and jejunum. For several authors, the location of adenomyomas is gastric (25-38%), duodenum (17-36%) and jejunum (15-21%), and the location in the stomach is: antrum (85%), pylorus (15% )^1,3and exceptionally in the body¹.

Magnus Alsleben was the first to describe this entity in 1903, the product of 5 cases found incidentally in necropsies⁵. Various authors consider this entity to be a hamartoma while others consider it a variant of a heterotopic pancreas^1,2. In some cases it coexists with heterotopic pancreas and in other cases it shows communication between the gastric lumen and the epithelial component of the lesion¹.

In 1909, Heinrich described 3 histological subtypes of heterotopic pancreas, considering the third type as “adenomyoma”, while Matsushita described his echoendoscopic findings and related them to Heinrich's description as follows¹:

Type 1: Exocrine and Endocrine Pancreas (Heterotopic Pancreas); Echo endoscopy shows indistinct margins, heterogeneous appearance and location between the third and fourth layers.

Type 2: Exocrine Pancreas without islets (Heterotopic Pancreas); echo endoscopy shows similar to type 1 but localization only in the third layer.

Type 3: Only ducts (adenomyoma); Echo endoscopy shows a small anechoic nucleus with thickening of the fourth layer.

The ages of presentation are variable, with the youngest patient being a 1-week-old neonate and the oldest being an 81-year-old person²; To date, 52 cases have been described in the literature up to 2017^1,4with the most frequent age of presentation being between the fourth and sixth decade of life^1,4with no gender predilection¹. Associated conditions may include annular pancreas, Gardner syndrome with duodenal adenomas, and gastric duplication¹.

The clinic is diverse, and can range from the asymptomatic which are discovered during a laparoscopy or necropsies^1,3, with the most reported cases being those associated with non-specific symptoms such as nausea, vomiting, epigastric pain, hematemesis, anemia, melena^1,3,4and even reaching intermittent pyloric obstruction³. Likewise, cases of secondary peritonitis due to perforation have been described. Making a preoperative diagnosis is difficult, because most of the symptoms are not specific, in addition to the few cases described in the literature^1,3.

For diagnosis, endoscopy is not usually very effective because it manifests as a submucosal lesion, in addition to not being able to differentiate between hamartoma and leiomyoma, melanoma, lymphoma, carcinoid tumor, Kaposi's sarcoma, GIST or eosinophilic granuloma³. For which, all these injuries must end up in surgical management to ensure a correct diagnosis^2-4.

Despite being considered a benign lesion, the potential for malignant transformation does exist^1-3being less than 2%⁴. The literature has described a case of gastric adenomyosis with malignant transformation of its glandular center². The use of endoscopic technologies for the resection of this type of lesion has not been reported; however, in retrospective studies it has been determined that these lesions have been resected using this technique without further complications^2,4. Most of the reviewed series indicate the open or laparoscopic surgical approach as the ideal management option.

CONCLUSIONS

Gastric adenomyoma is a rare benign pathology, difficult to diagnose clinically, which is usually diagnosed after the study of surgical specimens. It should be considered as a diagnostic presumption when previous studies are inconclusive; likewise, surgical management should not be delayed due to a lack of etiology, since this can generate unnecessary delays that could lead to clinical deterioration in patients.