HYPERVISCOSITY SYNDROME IN DISSEMINATED BREAST ADENOCARCINOMA

Circulation within the bloodstream of mucin derived from mucin-produci ng adenocarcinomas has been documented infrequently but has been assoc iated with vascular occlusion, organ infarction, and hyperviscosity. T he nature of the mucin and the therapeutic role of plasmapheresis in t his condition has not been reported. A 64-yr-old female, who had under gone a mastectomy 3 yrs previously for an infiltrating mucinous breast adenocarcinoma, presented with-dementia. A blood film showed marked r ouleaux and a bluish background. No abnormal bands were detected on pl asma protein electropheresis. Blood, serum and plasma viscosity were a bove the range of readability of the viscometer. A bone marrow biopsy showed replacement with tumor similar to the original. Repeated plasma phereses substantially reduced viscosity and temporarily improved her mental state. Post mortem revealed numerous infarcts with eosinophilic mucoid material in the lumen of many small vessels. That the offendin g plasma constituent was a sialomucin was suggested by mucin stains of the tumor and peripheral blood, a plasma sialic acid level 10 x norma l and a substantial fall in viscosity after in vitro treatment of plas ma with neuraminidase.