Choroidal neuroendocrine neoplasia in a dog.

OBJECTIVE: To report onset and progression of clinical signs of a neuroendocrine neoplasm (NEN) presumed metastatic to the choroid in a dog. ANIMALS STUDIED: A 7.5-year-old female spayed German shepherd dog mix referred for advanced imaging and evaluation of a subretinal mass in the right eye. PROCEDURES: Procedures performed included general physical and ophthalmic examinations; ocular, orbital, and abdominal ultrasonography; thoracic radiographs; cranial magnetic resonance imaging; serologic testing for infectious agents; analysis of hematologic as well as serum and urine biochemical parameters; echocardiography; electrocardiography; cytologic assessment of lymph nodes; and histopathology and immunohistochemistry of the enucleated globe. RESULTS: Examination and imaging identified a pigmented mass within and expanding the superior choroid. Following enucleation, a choroidal NEN with tumor emboli in scleral blood vessels was diagnosed by histopathologic assessment and confirmed by immunohistochemical labelling. Despite extensive and repeated diagnostic testing over many months, a putative primary site was not identified until 19 months after the initial ocular signs were noted. At that time, a heart-base mass and congestive heart failure were highly suggestive of a chemodectoma. CONCLUSION: This comprehensive report of a NEN presumed metastatic to the choroid in a dog suggests that ocular disease can be a very early and solitary sign of NEN in the dog.

Choroidal melanocytic tumors in dogs: A retrospective study.

OBJECTIVE: To describe clinical features of dogs diagnosed with choroidal melanocytic tumors at a veterinary teaching hospital. ANIMALS STUDIED: Retrospective case series of 13 dogs (14 melanocytic tumors) with choroidal melanocytic tumors. PROCEDURES: Medical records of dogs evaluated by the Cornell University ophthalmology service with a clinical diagnosis of a choroidal melanocytic tumor between 2008 and 2020 were reviewed. A choroidal melanocytic tumor was clinically defined as any well-demarcated, raised pigmented choroidal lesion underlying the retina. Histopathology results were consulted when available. Signalment and clinical features were recorded, including fundoscopic location, histopathologic findings, treatment, and outcome. RESULTS: Choroidal melanocytic tumors were identified in 14 eyes of 13 dogs. The mean (±standard deviation) of dogs was 8.6 (±3.5) years. Seven different breeds were represented, with Labrador/Labrador mix being the most common. Ten of the 14 melanocytic tumors were diagnosed incidentally. Four dogs presented for vision loss and ocular discomfort, and diagnosis was made on histopathology examination following enucleation. Pulmonary metastasis was suspected in one dog with an incidentally found choroidal melanocytic tumor OD. Fundoscopic location was available for 8 melanocytic tumors, with 6 (75%) located in the tapetal fundus. Histopathologic diagnosis was melanocytoma for 3 and malignant melanoma in 1 globe, with optic nerve head invasion in 50%. Local recurrence was not seen in any orbit following enucleation. CONCLUSION: Choroidal melanocytic tumors are uncommon in dogs. Metastasis appears to be rare and was only suspected in one dog, but intraocular tumor growth can lead to retinal detachment, glaucoma, and necessitate enucleation.

A case of primary choroidal malignant melanoma in a cat.

This report describes the clinical presentation, diagnosis, histological lesions, and prognosis of a primary choroidal malignant melanoma in a 15-year-old cat. The animal was presented for unilateral blindness. On ocular examination, a raised pigmented mass protruding from the posterior pole into the vitreous body was observed by diffuse transillumination and indirect ophthalmoscopy. Ocular ultrasound and computer tomography (CT) scan confirmed localization of the tumor to the posterior segment. The diagnosis of primary choroidal melanoma was confirmed by histopathology after enucleation. To our knowledge, this is the first reported case of a feline malignant melanoma with a primary choroidal localization without iris involvement.

Oculocardiac reflex in a dog caused by a choroidal melanoma with orbital extension.

A 7 yr old mixed-breed dog was presented with a choroidal melanoma of the left eye that had penetrated the sclera, producing an orbital mass. Bradycardia was detected on auscultation. The bradycardia resolved after exenteration of the orbit and was therefore presumed to be associated with the oculocardiac reflex.

Epibulbar melanoma in a foal.

A case of epibulbar melanoma in a 6-month-old, gelded, chestnut Hanoverian foal is reported. The location and clinical appearance upon initial presentation led to the tentative diagnosis of staphyloma or a congenital mass of unknown origin. An attempt was made to surgically excise the mass under general anesthesia, but due to its infiltrative nature and intraoperative appearance, most, but not all was removed without compromising the integrity of the globe. Histopathological evaluation revealed a multinodular to packeted, poorly demarcated, unencapsulated, infiltrative exophytic melanocytic neoplasm composed of bundles and nests of plump spindloid to polygonal heavily pigmented epithelioid neoplastic cells interspersed with pigment-laden macrophages within a fine fibrovascular stroma. Upon examination after enucleation, neoplastic cells were found to infiltrate into the lateral cornea, sclera and the choroid. This is a unique case of an epibulbar melanoma with choroidal invasion in a foal. Based on the sudden onset and rapid growth as well as the histological evidence of invasion, well-differentiated features, heavy pigmentation, and no apparent mitoses, this neoplasm was considered to be a low-grade malignant melanoma. At 14 months after excision there is no evidence of recurrence.

Choroidal melanoma in a dog.

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.

Canine choroidal melanoma with metastases.

A 3-year-old-female, spayed Golden Retriever was examined for a unilateral retinal detachment with exophthalmos. Ultrasonographically, a mass was detected with intra- and extraocular extension. The orbit was exenterated and the dog recovered uneventfully. Histopathologic diagnosis was a primary choroidal melanoma with orbital extension, however, the behavioral and cytologic features were benign. Routine examinations postsurgically were nonremarkable. Twenty-one months after surgery the dog was euthanized for respiratory collapse with radiographic signs of metastasis. Necropsy revealed black lesions in the lung and liver. Histopathologic diagnosis was metastatic melanoma with morphology and behavior identical to the primary choroidal melanoma. This is the first definitive case of a canine choroidal melanoma with metastasis.

Choroidal melanoma in a dog.

A 7-year-old male Great Dane dog was presented with blindness and a hemorrhagic retinal detachment in the right eye. Ocular ultrasonography revealed a conical-shaped mass in the posterior segment that protruded into the vitreous cavity. Histologic examination of the enucleated eye revealed a heavily-pigmented melanocytoma arising from the choroid lateral to the optic disc.

Choroidal melanoma in a dog.

B-scan ultrasonography of the right eye of a 6-year-old sexually intact female mixed-breed dog revealed complete retinal detachment and a semiconical solid mass of tissue that projected from the area of the optic disc into the vitreal space subretinally. Microscopic examination of an ultrasound guided fine-needle aspirate of the mass revealed a moderate number of mildly pleomorphic melanocytes. Histologic examination of the excised globe revealed a large, heavily pigmented intraocular neoplastic mass in the choroid around the optic nerve, bulging into the subretinal space. The histologic diagnosis was benign choroidal melanoma, with invasion into the intraocular portion of the optic nerve. In dogs, tumors of melanocytic origin are the most common primary ocular neoplasm, but primary choroidal melanocytic neoplasms are the rarest of this type.

Choroidal melanomas in dogs.

The clinical and morphological features of intraocular melanocytic masses that originated in the choroid of five dogs were compared. Two of the cases had been reported previously and the authors have examined the pathological material. Histologically, the choroidal melanocytic tumors had several features in common and appeared to be entities distinct from melanocytic tumors of the anterior uveal tract or the epibulbar region. The tumors were well-delineated with tapered edges. They occurred in the posterior quadrant and two tumors had infiltrated the optic nerve. The tumors contained plump, strap-like polyhedral cells, with minimal nuclear anaplasia and no mitotic figures. The retina overlying the tumor mass was detached, and the retinal pigment epithelium in this area was swollen and contained intracytoplasmic autofluorescent lipopigment. In two cases, the basement membrane of the retinal epithelium was disrupted by the tumor and pigmented cells infiltrated into the retina, the subretinal space, and the posterior chamber. In one case, retinal detachment was complete and accompanied by intraocular hemorrhage. Melanocytic tumors of the canine choroid have features in common with choroidal nevus and melanocytoma in human eyes.

Benign melanoma of the choroid in a beagle: ophthalmological, light and electron microscopical investigations.

A pigmented choroidal tumor was diagnosed in a 13-month-old male beagle. The tumor was observed ophthalmoscopically over a period of seven years. Light and electron microscopical features are those of a benign melanocytic tumor with marked histological similarities to uveal nevus in man.

Squamous cell carcinoma in a cat with intraocular and orbital metastases.

A well-differentiated squamous cell carcinoma metastasized to the choroid and retrobulbar tissues surrounding the optic nerve sheath in the left eye of a 15-year-old white female domestic cat. The tumor originated either in the external auditory meatus or in the middle ear and extensively infiltrated the neighboring soft tissue and bone.