Gastric metastasis of invasive lobular breast carcinoma

ABSTRACT

INTRODUCTION: Malignancies metastasizing to the stomach are rare and occur during the late stages of malignancy. Primary malignancies associated with gastric metastases include melanoma, esophagus, lung, renal cell carcinoma and breast. Of patients with metastatic breast cancer, one review reported a 0.3% incidence rate.We report a patient with known metastatic breast cancer to the bone and healing gastric ulcers found to have biopsy-proven breast cancer metastasis to the stomach. CASE DESCRIPTION/METHODS: A 74 year-old female with a past medical history of invasive lobular carcinoma of the breast complicated by bone metastases presented to an outpatient clinic for hospital follow-up. Although originally presenting to the hospital secondary to hematemesis, esophagogastroduodenoscopy (EGD) findings reported a pyloric ulcer with a bleeding vessel requiring epinephrine injections and heater probe cauterization. The ulcer was likely due to nonsteroidal anti-inflammatory drug (NSAID) use. She was discharged with a proton pump inhibitor twice daily with no further bleeding. Follow-up EGD reported ulcer healing;however, antral thickening was noted. Antral biopsies reported poorly differentiated adenocarcinoma with negative staining for cytokeratin 20 and CDX2 whereas estrogen receptor staining reported nuclear positivity in the neoplastic cells with mammaglobin suggesting breast cancer as the primary source. She was continued on palliative chemotherapy with palbociclib, letrozole, and denosumab. Unfortunately, she suffered frequent admissions for recurrent gastrointestinal hemorrhage and eventually passed away due to complications of coronavirus disease 2019. DISCUSSION: Metastases to the stomach are a rare complication of breast cancer. Such etiologies could be considered in breast cancer patients with recurrent gastrointestinal bleeding. Given her history of a gastric ulcer secondary to NSAID use, symptoms of hematemesis was attributed to gastric ulcers. However, gastric mucosal irregularities are not always obvious with metastatic lesions. Furthermore, up to 30% of cases may be missed due to metastatic spread to deep mucosal layers. Given this, in patients with a history of malignancy, suspicion for metastatic lesions should remain high especially if they have gastric mucosal irregularities. These should always be investigated with biopsies to prevent delays in management.