Hematoxylin and eosin stain; magnification, 200. consisted of severe multifocal pyogranulomatous inflammation intermixed with necrosis, fibrin, and broad, infrequently septate, thin-walled fungal hyphae. Immunohistochemistry revealed fungal hyphae characteristic of Mucormycetes (formerly Zygomycetes), and PCR analysis identified the organism asBasidiobolusspp. Dissemination of the fungus beyond the aorta was not noted. Spontaneous aortic aneurysms have been described in nonhuman primates, but this is the first reported case of a ruptured spontaneous aortic aneurysm associated with entomophthoromycetic infection in a sooty mangabey. A mycotic aneurysm is a local, irreversible dilatation of an artery associated with destruction of the vessel wall by infection.41Mycotic aneurysms can result from infection of the arterial wall or can occur due to secondary infection of a previously existing aneurysm.41Despite the use of the term mycotic to denote appearance of fresh fungus vegetations,20,34the majority of these aneurysms are caused by bacteria and only rarely by fungi.13Currently, this term is used broadly to describe any infected aneurysm CiMigenol 3-beta-D-xylopyranoside regardless of Rabbit Polyclonal to APLP2 its etiology.28Aneurysms can be classified as true aneurysms, which involve all layers of the arterial wall, and false aneurysms (hematomas), which form outside the arterial wall due to a leak in the artery.38 Mycotic aneurysms are rare in humans10and can occur in the cerebral or systemic circulation of patients with endocarditis, in whom septic emboli can occlude the vasa vasorum or the entire arterial lumen, damaging or destroying the muscle layer of the vessel.1,35The subsequent CiMigenol 3-beta-D-xylopyranoside intraarterial pressure causes dilatation and aneurysm formation.42Although these aneurysms can vary in size or even disappear during treatment of the underlying etiology, they are always life-threatening, as they develop rapidly and may rupture days, weeks, months, or even years after successful therapy.45,53Mycotic aneurysms can be solitary or multiple and can occur anywhere in the body, including the left ventricle; coronary artery; abdominal aorta; and femoral, superior mesenteric, carotid, iliac, and brachial arteries.9,2730 Rupture of an aortic aneurysm in humans can occur spontaneously due to trauma, increased diastolic pressure or anteroposterior diameter, or chronic obstructive pulmonary disease.9In animals, trauma is a more common than a spontaneous event.38Ruptured mycotic aortic aneurysms associated with bacterial infections have occurred in humans,21,40but those caused by fungi are rare.46A case of a horse with an aneurysm in the aortic arch associated withAspergillusinfection has been reported.38Spontaneous aortic aneurysms have been diagnosed in nonhuman primates including CiMigenol 3-beta-D-xylopyranoside gorillas (Gorillaspp.); squirrel (Saimirispp.), howler (Allouattaspp.), capuchin (Cebusspp.), patas (Erythrocebus patas), African green (Chlorocebus aethiops), and spider (Atellesspp.) monkeys; and pygmy chimpanzees (Pan paniscus).5,7,8,24,25Dissecting aneurysms have been seen in nonhuman primates used as experimental models of atherosclerosis.24Our report describes a unique case of a ruptured spontaneous aortic aneurysm associated with entomophthoromycosis in a sooty mangabey. == Case Report == == History. == This 21-y-old female mangabey was born at the Field Station of the Yerkes National Primate Research Center and was housed in accordance with theGuide for the Care and Use of Laboratory Animals18and Animal Welfare Act Regulations.2,3She had been maintained in a social colony in an indooroutdoor compound since birth and was fed a standard monkey chow diet (Purina LabDiet 5037, PMI, St Louis, MO) with daily approved enrichment. A physical examination and diabetes screening performed 3 mo earlier did not reveal any significant findings. No significant clinical signs were reported, and she had been observed eating and acting normally approximately 1 h prior to being found dead in the indoor housing area. == Pathology. == At necropsy, she weighed 7.25 kg and was in good body condition. A large amount of clotted blood filled the left pleural space around the lung lobes (Figure 1 A). The wall of the thoracic aorta was moderately thickened and focally perforated (diameter, approximately 0.15 cm;Figure 1 B and C). The perforation had smooth edges and clotted blood adhered to the tunica intima and adventitia (Figure 1 B and C). The tunica intima had multiple, firm, pale yellow.