Feline Systemic Reactive Angioendotheliomatosis: Eight Cases and Literature Review

Abstract

Abstract.A rare, multisystemic intravascular proliferative disorder was identified postmortem in eight cats. The majority of these cats died or were euthanized following episodes of dyspnea, lethargy, and anorexia. Microscopic examination revealed occlusive, intraluminal proliferations of spindle cells within small vessels. The heart was consistently involved, and myocardial dysfunction was the probable cause of illness in all cats. Immunohistochemically, the majority of intravascular cells expressed von Willebrand factor, and a smaller number expressed smooth muscle actin, compatible with a dual population of endothelial cells and pericytes, suggesting a reactive rather than a neoplastic process. Four cases of a similar feline vascular disorder from the veterinary literature are reviewed. The histopathology resembles reactive angioendotheliomatosis in humans, a benign cutaneous intravascular endothelial and pericytic proliferative condition. However, in contrast, this feline disease is multisystemic and fatal. We propose the name ''feline systemic reactive angioendotheliomatosis'' for this unique, idiopathic disorder of domestic cats.

Systemic Reactive Angioendotheliomatosis-like Syndrome in a Steer Presumed to be Persistently Infected with Bovine Viral Diarrhea Virus

“…7,9,10,20,22 IHC staining of the intraluminal spindle cells are consistent with proliferation of both endothelial cells and pericytes, as demonstrated for FSRA. 7,9,10,20,22 In addition, the distribution of affected vessels in this steer is similar to that reported in most cases of FSRA, with the heart being most consistently and severely affected.…”

“…11 Systemic reactive angioendotheliomatosis, a rare entity of unknown cause, has recently been described in cats. 10 This disease is characterized by the intravascular proliferation of plump endothelial cells and occasionally surrounding pericytes within multiple organs. Arterioles within the myocardium are the most commonly and severely affected, with lesser but fairly consistent involvement of small vessels within kidneys, spleen, lymph nodes, and intestine.…”

“…7 Vascular lesions similar to those reported in cats with systemic reactive angioendotheliomatosis have not been previously documented in other domestic or laboratory animal species. 10 In this report, we describe unusual intraluminal proliferations involving arterioles in multiple organs of an approximately 2-year-old Corriente steer that was persistently infected (PI) with bovine viral diarrhea virus (BVDV). Distribution and character of the vascular lesions in this steer were strikingly similar to those reported in cats with feline systemic reactive angioendotheliomatosis (FSRA).…”

“…9,10,20 In all but 2 of the reported cases of FSRA, no cause of the vascular lesions could be determined; however, a reactive or hyperplastic process, possibly in response to thrombosis, vasculitis, or an infectious agent, was believed to be more likely than a neoplastic process. 9,10,20,22 One cat with FSRA had hematologic evidence of thrombotic thrombocytopenic purpura (TTP), to which the widespread and advanced vascular lesions were presumably attributed. 7 TTP, a thrombotic microangiopathy of humans, involves the formation of platelet thrombi due to the accumulation of unusually large multimers of vWF as a result of either an acquired or a genetic defect in vWF metalloprotease.…”

Pulmonary Intravascular Hemangiosarcoma in a Cat

“…Although feline intravascular proliferative disorders are extremely rare, some cases of feline systemic reactive angioendotheliomatosis (FSRA) have been described [2]. FSRA are characterized by multisystemic intraluminal endothelial and pericyte proliferation without cellular atypia, and the heart is the most commonly and severely affected.…”