PRIMARY IGG SECRETING PLASMA-CELL TUMOR IN THE GASTROINTESTINAL-TRACTOF A DOG

A mixed-breed dog, evaluated because of a chronic history of diarrhea and intestinal bleeding, was found to have a multilobular mass involvi ng the intestine. Surgical resection of the mass necessitated an ileoc olic anastamosis. On the basis of histologic and electron microscopic appearance and staining characteristics, a tentative diagnosis of inte stinal carcinoid was made. Recovery was uncomplicated; the owners decl ined further diagnostic tests or treatment. Eight weeks later, the dog was reexamined because of signs consistent with hyperviscosity syndro me and hyperproteinemia. At the owner's request, the dog was euthanati zed. At necropsy, extensive metastases to liver and lymph nodes, but n ot to bone, were seen. Reevaluation of the intestinal mass supported c lassifying the tumor as an IgG-secreting extramedullary plasmacytoma. This case underscores the need for additional histologic techniques, e specially when confronted with an unusual manifestation of hyperprotei nemia.