An increase of CA 19.9 as the first clinical sign of ileocecal valve metastasis from breast cancer.

CASE REPORT: The case of a breast cancer patient with a progressive increase of CA 19.9 that indicated gastrointestinal metastasis is reported. After the observation of an increased CA 19.9 serum value (104.00; n.v. 0.0-37.00) a colonoscopy was performed. This examination showed the presence of an erythematous and granular zone near the ileocecal valve. Histological examination of biopsies taken during the colonoscopy revealed atypical monomorphic cells between the organoid pattern of the colon-type ducts. Immunohistochemical staining was positive for cytokeratin 7 and for estrogen receptors, consistent with metastatic epithelial malignancy. After eleven months, the patient presented with signs of intestinal obstruction, requiring an ileocolic bypass. At definitive histological examination, the tumor exhibited features of mammary metastases.

CONCLUSION: This is the first report in the literature of an ileocecal valve metastasis from breast cancer diagnosed by an increase of CA 19.9, which is a marker of primary colorectal carcinoma.