Jessemel Estrada, MD1, Jordan Malone, DO1, Ernesto Zamora, MD1, Jose Aguirre, MD2 1University of Texas Medical Branch, Galveston, TX; 2University of Texas Medical Branch, Galveston,, TX
Introduction: The most common etiologies of pyloric stenosis in adults are malignancy and peptic ulcer disease. Metastatic disease from a non-gastrointestinal primary malignancy is rare and even rarer in the absence of a previously diagnosed primary cancer. We present the case of an elderly female who was diagnosed with metastatic invasive lobular adenocarcinoma of the breast via gastric antral biopsy after presenting with symptoms of Gastric Outlet Obstruction. To our knowledge, this is the first reported case of a primary breast cancer metastatic to the stomach first diagnosed via endoscopic gastric biopsy without a previously known breast mass.
Case Description/Methods: A 71-year-old female presented with 2 weeks of early satiety, acid reflux, and vomiting undigested food. Computed tomography (CT) abdomen showed GOO. Esophagogastroduodenoscopy (EGD) showed severe pyloric stenosis and outlet obstruction. The pyloric canal was dilated with improvement in symptoms. Subsequent dilation showed that the pyloric stenosis had notably worsened after 3 weeks with a small area of abnormal mucosa in the gastric antrum that was biopsied. Pathology showed adenocarcinoma with signet-ring cell features, suspicious for metastatic breast cancer. CT thorax showed an enlarged axillary node but no discrete breast mass. Bilateral tomosynthesis and breast ultrasound showed a 6 mm left breast mass. Biopsy of the mass and node confirmed metastatic lobular breast cancer. Positron emission tomography (PET) demonstrated additional metastasis to the left iliac bone and a few concerning lung lesions. She was started on palbociclib and letrozole with plans for palliative gastric surgery. Her procedure has been postponed due to new-onset atrial fibrillation requiring anticoagulation.
Discussion: Breast cancer is the most common cancer in women worldwide with 2.3 million diagnosed cases in 2023. The most common sites of metastasis are the brain, bones, lungs, and liver. Gastric metastasis is rare and more commonly seen with invasive lobular carcinoma as compared to ductal carcinoma. Gastric metastases are more commonly seen in patients with disseminated disease but can infrequently present and mimic a primary gastric tumor. Endoscopic evaluation with biopsy is important in all cases and can serve as comparison when a primary breast tumor has already been recognized. It is more difficult, as in this case, when the endoscopic biopsy serves as the first tissue diagnosis of the primary cancer in the absence of a previously known focal mass.
