Case report of gastric outlet obstruction from metastatic lobular breast carcinoma

BACKGROUND The most common malignancy to cause gastric outlet obstruction is primary gastric adenocarcinoma and it is followed by carcinoma of the pancreas and gallbladder. Herein, we report a case of gastric outlet obstruction secondary to metastatic lobular breast carcinoma. CASE PRESENTATION Fifty-seven year old Caucasian female with recently diagnosed metastatic lobular breast carcinoma to skin was referred to gastroenterology for evaluation of dyspepsia and dysphagia. She has past medical history significant for acid reflux and Clostridium difficile colitis. Computed tomography of her abdomen showed diffused bowel wall thickening without evidence of bowel obstruction. Due to persistent abdominal pain, an upper endoscopy was performed. The upper endoscopy showed gastritis and gastric stenosis in the gastric antrum. These lesions were biopsied and dilated with a balloon dilator. The biopsy of the gastric antrum later showed a metastatic carcinoma of breast origin with typical tumor morphology and immune-phenotype. CONCLUSIONS Differentiating metastatic breast carcinoma from primary gastric adenocarcinoma cannot be done using histological examination alone. Immunohistochemistry is needed to differentiate the two based on staining for estrogen and progesterone receptors. The presence of gross cystic disease fluid protein 15 is also suggestive of metastatic breast carcinoma. The stomach has a significant capacity to distend (up to 2-4 L of food) and malignant gastric outlet obstruction is often undetected clinically until a high-grade obstruction develops. Our case demonstrates valuable teaching point in terms of broadening our differentials for gastric outlet obstruction. When patients present with gastric outlet obstruction, both non-malignant and malignant causes of gastric outlet obstruction should be considered. Once adenocarcinoma has been determined to be the cause of gastric outlet obstruction, further immunohistochemistry is needed to differentiate breast carcinoma from other carcinomas.