Breast carcinoma metastasising to the gastric wall and the peritoneum: what physicians need to know.

Breast cancer is the most common cancer among women in the USA and rarely metastasises to the gastric wall. We present a case of a 69-year-old woman with medical history of stage II-B breast cancer who presented with epigastric abdominal pain and black tarry stools. CT scan of the abdomen showed moderate gastric wall thickening and ascites. The patient underwent an esophagogastroduodenoscopy (EGD) with endoscopic ultrasound (EUS) for a fine-needle biopsy, which was negative for malignancy. Based on her presentation, we kept a high index of suspicion for peritoneal carcinomatosis and malignancy. The patient underwent laparoscopic wedge resection of the gastric wall with biopsies of gastric wall and peritoneum. Both biopsies confirmed the diagnosis of metastatic invasive lobular breast carcinoma. Our case highlights the importance of diagnostic laparoscopy and EUS in the setting of negative EGD biopsy results with a high suspicion of breast cancer metastasis to gastric wall.