Unusual serum electrophoresis pattern in a woman with pancreatic carcinoma.

A 51-year-old woman presented with progressive severe icterus associated with advanced inoperable pancreatic carcinoma. Biopsy of the liver revealed metastasis of a moderately differentiated adenocarcinoma, possibly of pancreatic origin. Imaging studies did not show any primary tumor in the pancreas but did reveal a deep vein thrombosis of the left lower extremity and a pulmonary embolism. Bone scans revealed metastases. The patient began treatment with chemotherapy (gemcitabine), radiotherapy to alleviate pain, and placement of a percutaneous transhepatic stent in the right biliary system because of progressive icterus. Routine biochemical investigation of the patient’s serum revealed increased total bilirubin (275 mol/L, reference value 22 mol/L), which consisted mainly of direct bilirubin (215 mol/L, reference value 4 mol/ L). The cytosolic liver enzymes alanine aminotransferase (115 U/L) and aspartate aminotransferase (143 U/L) were moderately increased. The serum protein concentration was 68 g/L (reference interval 60–85 g/L), but capillary electrophoresis of serum proteins (CAPILLARYS 2, Sebia) demonstrated a low albumin fraction together with a marked additional peak observed between the and the region (Fig. 1). Results of immunofixation with antibodies against G, M, and A heavy chains and and light chains were negative, indicating that this additional electrophoretic fraction did not indicate the presence of a paraprotein. Agarose gel electrophoresis confirmed the abnormal pattern, ruling out analytical interference caused by atypical ultraviolet absorbance.