ABSTRACT. A 7-year-old intact female golden Retriever was referred for evaluation of an intraorbital mass of the left eye. Based on ophthalmoscopy, ultrasonography and magnetic resonance imaging (MRI), the tentative diagnosis was made as an intraocular neoplasia, especially choroidal melanoma. The orbital exenteration of the affected eye was performed. The mass was histologically diagnosed as malignant choroidal melanoma. No signs of recurrence and metastasis were detected by thoracic radiographs, blood examinations and MR images, and the dog was clinically healthy for 23 months after operation. KEY WORDS: canine, choroidal melanoma, magnetic resonance imaging (MRI).J. Vet. Med. Sci. 67(8): 821-823, 2005 Melanomas are the most common primary ocular tumor in dogs, although primary ocular tumors are relatively rare [1]. Most of primary melanomas in dogs arise from the anterior uveal tract such as the iris and ciliary body [1,4,11], and primary choroidal melanoma is less common among primary ocular melanomas [2,9]. Previous studies documented 4% of canine ocular melanomas to be of the choroidal origin and the behavioral and cytologic features were benign [3,11]. Another report on benign choroidal melanoma in a dog showed that the tumor lesion did not change for 7 years, similar to that of human uveal nevus [10]. But the other case of canine choroidal melanoma with metastasis was reported [4]. The present paper describes ophthalmoscopy, magnetic resonance imaging (MRI), histopathology and a 23-month follow up of a choroidal melanoma in a dog.A 7-year-old intact female golden Retriever was referred to Veterinary Medical Center (VMC) at the University of Tokyo for evaluation of an intraorbital mass of the left eye. Two months prior to referral, the owner noticed the blindness of the left eye of the dog and admitted to a practitioner. Opthalmic examinations revealed mydriasis and loss of menace reflex and direct pupilary light reflex in the left eye. Consensual pupilary light reflex was lost in the right eye. Then the patient was referred to another practitioner to examine the cause of the vision loss of the left eye, where the black pigmented and edematous retina around the optic nerve disk were found on ophthalmoscopy and diagnosed as inflammation of the nerve disk. The dog was treated with the taper dose of prednisone with an initial dose of 2 mg/kg/ day. Two weeks later, the dog received ophthalmoscopy and was revealed that the edematous area was reduced but the black-pigmented area was enlarged and rose up toward the vitreous. Ultrasonogram of the affected eye revealed the solid mass lesion which overlaying the optic disk area. Then the dog was referred to VMC for the detail evaluation of the solid mass by MRI.On physical examination, the dog was clinically normal. Complete blood count and blood chemistry revealed no abnormal findings. On ophthalmic examination, the menace reflex and the pupilary light reflex were lost as seen in the practitioners. The intraocular pressure was within the normal range in both ey...

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ABSTRACT. A 3-month-old female tortoise-shell cat showing azotemia died with a marked swollen abdomen. Necropsy revealed a huge perirenal cyst (8.5 × 6.0 × 4.5 cm) on the ventral aspect of the right kidney. The cyst was filled with the pellucid yellow fluid with a smell of urine. The lumen was connected with irregularly dilated renal pelvis by a narrow channel passing through the renal parenchyma. The cyst was lined by epithelial cells and its wall was consisted of collagen fibers and smooth muscle cells as that of the renal pelvis and ureter. Renal parenchyma adjacent to the channel showed interstitial infiltration of the lymphoid cells. The cyst was a diverticulum of the renal pelvis due to an impaired development. KEY WORDS: feline, perirenal cyst, pyelocaliceal diverticulum.J. Vet. Med. Sci. 67(3): 329-331, 2005 Cystic diseases of the kidney in cats are divided into two types as a renal cyst and a perirenal pseudocyst [5]. The former that may occur in association with inherited, developmental, or acquired diseases is recognized in the renal parenchyma and are defined as a fluid-filled sac lined by an epithelium. On the other hand, the latter has been used to describe renomegaly caused by accumulation of fluid between renal parenchyma and the surrounding capsule so that it had no epithelial lining and the cause of the disorder is not known and the morphogenesis has not been yet fully investigated [1,3,5]. The words of capsulogenic renal cyst, capsular cyst and pararenal pseudocyst, capsular hydronephrosis or perirenal cyst have been used as a synonym of perirenal pseudocyst [5]. In the present report, we describe the perirenal cyst which has not been described before.A 3-month-old female tortoise-shell cat, weighing about 920 g showed a marked swollen abdomen, anorexia and dyschezia for the past month. The cause of abdominal enlargement was identified as accumulation of fluid. To lower intra-abdominal pressure, a total of 800 ml of the fluid was removed by aspiration with a syringe four times over a period of 3 weeks, however the abdominal turgidity showed no signs of recovery. A blood test that was performed 5 days before death showed an elevation in values of blood urea nitrogen (BUN; >140 mg/dl) and creatinine (Cr; 7.1 mg/dl). The cat died 40 days after the first admission.Necropsy was performed two hours after death and confirmed asites (about 15 ml) which was pellucid yellow with a smell of urine, formation of a huge fluid-filled cyst (8.5 × 6.0 × 4.5 cm, weighing about 190 g) on the ventral aspect of the right kidney (Fig. 1), a slightly swollen left kidney and hydrothorax. Accumulated fluid in the cyst of the right kidney was similar in content to that of the ascites (BUN; 43.2 mg/dl, Cr; 2.5 mg/dl). The free wall of the cyst was thin and the inside lining was smooth and white. On the other hand, the visceral cyst wall could not be separated from the right kidney. The lumen of the cyst connected with irregularly dilated renal pelvis through a narrow channel (Figs. 2 and 3). The ventral aspect of th...

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