Inflammatory breast cancer with refractory diarrhea: a case report.

Excessive amounts of vasoactive intestinal polypeptide (VIP) cause a special clinical syndrome characterized by secretory diarrhea, hypokalemia and dehydration. A careful clinical workup of a 62-year-old female admitted for refractory diarrhea revealed a neglected inflammatory right breast ductal carcinoma with VIP hypersecretion without any localized abdominal tumor. Immunohistochemistry of the breast biopsy showed neuroendocrine characteristics with positive staining for VIP, and Octreotide scan showed hyperfixation to the right breast and axilla. Primary therapy of breast cancer with hormones and chemotherapy achieved transitory regression of diarrhea, VIP level decrease, and tumor border reduction. Bilateral modified radical mastectomy and irradiation of the tumor failed to prevent liver and bone dissemination of the disease. Once more, partial response was obtained by octreotide and salvage chemotherapy; however, the patient died from progressive disease 23 months after initial diagnosis. To our best knowledge, this unusual presentation of a breast carcinoma with related VIPoma syndrome is the first reported case in the literature.