Metastases from lobular breast cancer as an unusual source of GI bleeding.

Abstract

e12557 Background: With the exception of malignant melanoma, metastases to the GI tract are rare, especially as a first presentation of malignancy. We report a series of patients with GI metastases from lobular breast carcinoma as an unusual source of symptomatic GI bleeding. Methods: We conducted an electronic database search to identify solid tumour patients (excluding melanoma) with metastases to the GI tract. We then analysed the database by tumour type. Results: 3 cases of proven metastasis to the GI tract were identified. All had lobular breast cancer metastases. The database contained 240 patients with breast cancer, identifying 63 with infiltrating lobular carcinoma, 2 with micropapillary and 175 with invasive ductal carcinoma The 1st case had had invasive ductal breast carcinoma 6 years previously and presented with fatigue and shortness of breath from anaemia. Colonoscopy revealed a polyp which was removed. Histopathology showed metastatic lobular breast carcinoma. Further investigation then confirmed an occult breast mass with identical pathology. The 2nd case presented with 18 months of abdominal pain, previous colonoscopy was normal. After onset of anaemia and 25kg weight loss, upper GI endoscopy showed a markedly thickened stomach with evidence of recent bleeding and biopsies confirmed metastatic lobular breast carcinoma. The 3rd case presented with abdominal pain, subsequent blood tests showing a raised CA125 with omental and ovarian masses. Surgical debulking showed metastatic lobular breast carcinoma, though no primary breast lesion was detectable with mammography, ultrasound and MRI. 3 years later, investigation of anaemia with colonoscopy showed a caecal polyp with histology confirming lobular breast carcinoma. Conclusions: Despite all common tumour types being represented in the database it is notable that all 3 cases with mucosal GI metastases had lobular breast cancer. Previous evidence suggests a long latent period from initial diagnosis of breast cancer to development of GI metastases however our report suggests it can occur earlier in the illness. Clinicians should consider this as a rare cause of GI bleeding and further research to understand the mechanism of mucosal metastasis in lobular breast cancer is needed.