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A 23-year-old Anglo-Arabian mare was presented with tachypnea, dyspnea, and pitting edema of the ventral thoracic subcutis. On necropsy, a tan to red, friable, irregularly shaped mass (23 × 20 × 18 cm) occupied the cranial mediastinum. Histologically, the mass was classified as a liposarcoma and was composed of short interlacing bundles of spindle-shaped to irregularly rounded cells with discrete, variably sized, clear cytoplasmic vacuoles, which were stained with oil red O in frozen sections of formalin-fixed tissue.

This multi-institutional report describes 8 cases of rhabdomyosarcoma in horses. Four neoplasms were in the tongue and other areas of the mouth or head, 2 were in the abdominal wall, and 1 each was in right shoulder muscles and heart. Four rhabdomyosarcomas that were less than 10 cm in diameter were treated by surgical excision or radiation with no recurrence. Two neoplasms greater than 10 cm in diameter in the abdominal wall and the right shoulder were considered inoperable and led to decisions to euthanize the horses. Two neoplasms were incidental findings at necropsy. All the neoplasms were classified as embryonal except for 1 pleomorphic rhabdomyosarcoma. These 8 cases were evaluated with 9 published case reports of equine rhabdomyosarcoma. For all cases, the most common sites were limb muscles (5/17) and tongue (4/17). Metastasis was reported in 4 of the previously published cases; none was found in this study.

Marked renal vascular changes, suggestive of hypertension, were present in adult western gray kangaroos (Macropus fuliginosus) from a single facility over a 14-year period. A subset of these kangaroos also had vague clinical nervous system deficits, including blindness. To characterize the vascular lesions, determine prevalence, and document other changes, case histories and archival tissue sections from 21 adult kangaroos (8 male, 13 female) that died or were euthanatized between 1994 and 2008 were reviewed. Relevant lesions included increased thickness of the renal arteriolar tunica media with smooth muscle hypertrophy and/or hyperplasia, accumulation of extracellular matrix within arterioles, increased vascular tortuosity, and varying degrees of juxtaglomerular hyperplasia. Renal tissue from two more severely affected animals was further examined by transmission electron microscopy, highlighting arteriolar endothelial cell hypertrophy and disruption of the medial architecture. Hypertrophy of arteries and arterioles in other organ systems was also present (3/21), including vessels in the brain and spinal cord of one animal with clinical neurologic signs. Four kangaroos had antemortem retinal detachment, a potential sequel of hypertension in humans and domestic mammals. The cause of these vascular lesions in this mob is uncertain. Lesions were not associated with an infectious disease process, age, underlying renal disease, or thyroid abnormalities. In the absence of other causes, hypertension was a differential. Further investigation into clinical significance and predisposing factors, such as genetics and diet, is warranted.