Microangiopathic Hemolytic Anemia Associated with Radiation-Induced Hemangiosarcomas

Abstract

A retrospective study of red blood cell parameters in 53 dogs with experimental radiation-induced hemangiosarcoma showed 24 had anemia. Morphologic alterations in red blood cells in peripheral blood films from anemic dogs included signs of regeneration (anisocytosis and polychromasia), hypochromasia, red cell fragmentation and acanthocytosis. The degree and type of red cell changes varied from dog to dog and generally correlated with the principal site of tumor involvement. Blood from dogs with tumors principally involving liver had red cell regeneration, fragmentation and acanthocytosis. Blood from dogs with tumors primarily involving the heart had only red cell fragmentation. Blood films from dogs with skeletal and pulmonary hemangiosarcomas were similar to blood films from dogs with hepatic hemangiosarcoma except that red cell alterations generally were less severe. Scanning and transmission electron micrographic evaluation of neoplastic tissue showed large amounts of fibrin within neoplastic vascular sinuses and disruption and distortion of red blood cells traversing these abnormal vascular beds. The red blood cell fragmentation syndrome associated with radiation-induced hemangiosarcomas therefore was considered to be a microangiopathic hemolytic anemia of localized origin.

Hemangiosarcoma of the third eyelid in a dog

“…In humans, exposure to thorium dioxide, arsenicals or vinyl chloride, are reported to be contributory factors 8,9 . In one study, a radiation‐induced HSA was experimentally produced in 53 dogs 10 . Cutaneous HSAs are found more frequently in dogs with poor pigmentation and light hair and may be associated with ultraviolet light exposure 11 .…”

Erythrocyte and Biochemical Abnormalities as Diagnostic Markers in Dogs With Hemangiosarcoma Related Hemoabdomen

“…Presence of acanthocytes in canine peripheral blood has been associated with various disorders including HSA . Acanthocytosis with HSA is not entirely understood, but is thought to occur because of direct damage to the RBC membrane or abnormal lipid metabolism .…”

Main symptom “chronic blood loss” in two horses with haemangiosarcoma

“…Die häma-tologischen Befunde bei Patienten mit einer disseminierten Tumormanifestation sind, ähnlich denen einer schweren Blutung, charakterisiert durch Anämie, Neutrophilie und Thrombozytopenie (Southwood et al 2000). In den vorliegenden Fällen erwiesen sich zahlreiche Gefäße, wie auch von Rebar et al (1980) (Southwood et al 2000). Im Gegensatz zur auch beim Pferd leicht klinisch zugänglichen kutanen Form des Hämangiosarkoms, erfolgte in zahlreichen anderen Fallbeschreibungen (Johnson et al 1988, Freestone und Williams 1990, Collins et al 1994, Jean et al 1994, Southwood et al 2000, Bausbacher et al 2002, Johns et al 2005) wie bei diesen beiden Stuten, erst post mortem der definitive Nachweis eines disseminierten Hämangiosarkoms.…”