title: Systemic AL amyloidosis associated with multiple myeloma in a horse.
abstract: AL amyloidosis is the most common type of systemic amyloidosis in humans, and it is frequently associated with multiple myeloma. But, AL amyloidosis is very rare in domestic animals. A 16-year-old Quarter horse gelding was diagnosed with systemic AL amyloidosis associated with multiple myeloma. Clinical problems were rapid weight loss, muscle atrophy, soft unformed stool, and ventral edema. Grossly, diffuse gastrointestinal hemorrhage, markedly thickened jejunal mucosa, and splenomegaly were present. Microscopically, diffuse severe amyloid deposits were present in the lamina propria of glandular stomach, duodenum, and jejunum. Much of the spleen and sternal bone marrow was replaced by neoplastic round cells, and multiple foci of amyloid were also present in the spleen and bone marrow. Electron microscopy revealed the neoplastic round cells to be of plasma cell origin, and the amyloid showed a strongly positive immunoreactivity with polyclonal anti-human immunoglobin lambda light-chain antisera. To our knowledge, this is the second report describing systemic AL amyloidosis in domestic animals-associated plasma cell neoplasia and the first associated with multiple myeloma, as is common in humans.
authors.affiliation: Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, PO Box 6023, Columbia, MO 65205, USA. kimdy@missouri.edu
authors.forename: D Y
authors.initials: DY
authors.lastname: Kim
authors.forename: H W
authors.initials: HW
authors.lastname: Taylor
authors.forename: S C
authors.initials: SC
authors.lastname: Eades
authors.forename: D-Y
authors.initials: DY
authors.lastname: Cho
mesh_terms: D000686:Amyloidosis / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D000818:Animals; D001853:Bone Marrow / Q000473:pathology; D017809:Fatal Outcome; D006651:Histocytochemistry / Q000662:veterinary; D006734:Horse Diseases / Q000473:pathology*; D006736:Horses; D007583:Jejunum / Q000473:pathology; D008297:Male; D046529:Microscopy, Electron, Transmission / Q000662:veterinary; D009101:Multiple Myeloma / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D013154:Spleen / Q000473:pathology