Gastric adenomyoma is a rare tumor with a benign course. Children may present with nonspecific symptoms but can also exhibit urgencies such as melena and gastric outlet obstruction (GOO). Surgical resection is the cornerstone in its treatment. Histologically, it is composed of epithelial elements surrounded by a smooth stroma. Herein, presents a rare case of gastric adenomyoma in a 12-year-old child to highlight the diagnostic dilemma and the importance of surgical resection and histopathology in management.
A 12-year-old boy presented with complaints of episodic, dull-aching pain in the left upper abdomen for the past 1 month. There was associated history of episodes of nonbilious vomiting with the pain. The child underwent upper gastrointestinal endoscopy elsewhere, where a submucosal bulge in the pyloric region was documented, and an endoscopic biopsy from the site of the bulge was suggestive of a spindle cell neoplasm. He was referred to our center for further management.
On presentation, his general condition was well preserved. On examining the abdomen, no lump or organomegaly was found. Ultrasonography (USG) of the abdomen revealed circumferential thickening in the distal body of the stomach. Subsequently, a contrast-enhanced computed tomography (CECT) scan of abdomen confirmed the presence of a heterogeneously enhancing mass in the anteroinferior wall of the gastric antrum causing luminal obstruction [Figure 1]a. This mass also showed focal fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET scan). Investigations were done to rule out tuberculosis and lymphoma as a possible cause of distal gastric and pyloric thickening.
With a working diagnosis of the gastrointestinal stromal tumor (GIST), an exploratory laparotomy was planned. A circumferentially thickened and bulky pylorus was found with normal duodenum and proximal stomach. The abnormal pylorus was completely excised [Figure 2]a, and a gastroduodenostomy was performed with a transanastomotic tube. The histopathology revealed the expansion of the submucosa and muscularis by smooth muscle cells [Figure 2]b. The presence of Brunner's glands [Figure 2]c, positive staining for periodic acid-Schiff [Figure 2]d and CK7 [Figure 2]e and negative staining for synaptophysin [Figure 2]f were consistent with the diagnosis of gastric adenomyosis. The margins of resection were free.
The patient was asymptomatic after a year of follow-up and a PET scan done (3 months after resection) did not reveal any FDG uptake. Serial long-term follow-up with USG has been planned to rule out local recurrences if any. A gastric adenoma is a rare cause of pediatric GOO. Endoscopic biopsy may miss the diagnosis, and therefore, complete surgical resection should be attempted after ruling out other common causes of GOO. The presence of characteristic histopathological findings should confirm the diagnosis.