Increased serum carbohydrate antigen 19-9 in relapsed ductal breast carcinoma

Increased serum carbohydrate antigen (CA) 19-9 is a quite uncommon manifestation of breast cancer both on early disease and on relapse. A 53-year-old woman with invasive ductal breast carcinoma underwent left-sided mastectomy. Two years later she palpated a subcutaneous mass at the mastectomy scar, arousing suspicion of local relapse. Surgery and histopathology revealed infiltration by breast adenocarcinoma and she was treated with chemotherapy. At that time serum tumor markers, carcinoembryonic antigen (CEA) and CA 15-3 were within normal range. Over the next six months she displayed an increase of serum CEA while serum CA 15-3 remained within normal range. In an attempt to search for a second neoplasm possibly of gastrointestinal (GI) origin, abdominal computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance cholangio-pancreatography (MRCP), endoscopy of the upper GI tract and colonoscopy were performed, as well as measurement of serum CA 19-9. While no indication of a GI neoplasm was detected, she displayed an over 10-fold increase of serum CA 19-9. The patient had also an X-ray mammography and technetium-99m hexakis-2-methoxyisobutylisonitrile ((99m)Tc-MIBI) scintimammography (SM). Whilst mammography was negative for contralateral disease recurrence, SM was suggestive of axillary lymph node involvement. Axillary lymph node dissection confirmed an extensive metastatic infiltration of these nodes by breast adenocarcinoma. Three months later serum CA 19-9 and CEA became normal. The interest of this case lies on the unexpected high serum CA 19-9 values found in a breast relapsed adenocarcinoma and in the important contribution of SM in diagnosing the axillary lymph node metastatic infiltration.