Immunohistochemical properties of ocular adenomas, adenocarcinomas and medulloepitheliomas

Malignant ocular teratoid medulloepithelioma in two cats

Medulloepithelioma is a type of rare primitive neuroectodermal tumour. Most medulloepitheliomas are intraocular and they have been most frequently reported in horses and dogs. A single feline case has been reported but the teratoid form has not been previously reported in cats. Two cats presented with rapidly expanding intraocular masses and ophthalmic examination revealed vascularized uveal tumours extending into the anterior chamber and vitreous chamber. Following enucleation, histopathological examination of each case revealed a focally extensive infiltrative neoplasm that replaced the uveal tract, with retinal detachment and scleral vascular invasion. Rosettes, medullary tubes and heterotopic tissue were present. During follow-up periods of 3.4 and 8.8 years, no evidence of orbital recurrence or metastasis was found in either cat. To the best of our knowledge, these are the first case reports of teratoid medulloepithelioma in cats. Although the risk of metastasis cannot be excluded, as in other species, these findings support enucleation as a curative intervention.

Pleomorphic iridociliary adenocarcinoma with metastasis to the cervical lymph node in a chinchilla (Chinchilla lanigera)

A tumor had formed in the right eye of a 14-year-old male chinchilla. The black-and-white-colored tumor occupied the entire eye except for the lens and had invaded extensively inside the orbit. Histologically, round, spindle- to polygonal-shaped tumor cells had proliferated in a solid-sheet arrangement. The tumor cells exhibited polymorphic nuclei ranging from round- to polygonal-shaped, as well as abundant cytoplasm, which occasionally contained melanin granules. In some areas, several cells were surrounded by the basal lamina. Additionally, the tumor showed cervical lymph-node metastasis. Upon immunostaining, the tumor cells were positive for epithelial markers (cytokeratin AE1/AE3, 8/18, and 20), S100, and vimentin. Consequently, we diagnosed primary pleomorphic iridociliary adenocarcinoma with lymph-node metastasis. This is the first report of iridociliary adenocarcinoma in chinchillas.

Intraocular sarcoma associated with lens capsule rupture and persistent hyperplastic primary vitreous in a dog

This case report describes the clinical findings and ocular pathology in an adult Golden Retriever diagnosed with an intraocular sarcoma. Nineteen s prior to diagnosis with a lens capsule rupture and intraocular sarcoma, the dog was diagnosed with persistent hyperplastic primary vitreous and uveitis based on clinical signs and the ultrasonographic appearance of the eye. Two years after enucleation, there was no evidence of metastatic spread of the sarcoma. The immunohistochemical characteristics of the tumor as well as the limitations and supportive evidence used in attempting to identify the histogenesis of the tumor are outlined.

Metastatic Iridociliary Adenocarcinoma in a Labrador Retriever

An enucleated left eye from a 15-year-old female spayed Labrador Retriever was received by the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) for histopathologic evaluation. Routine histologic preparation included staining with hematoxylin and eosin, and with alcian blue periodic acid-Schiff (PAS). At necropsy 9 months later, all grossly abnormal tissues (ipsilateral orbit and lung) were submitted to the COPLOW for histopathologic evaluation. Histopathologic evaluation of the globe revealed extensive invasion of the uvea and sclera by a pleomorphic cell population that formed disorganized cords and exhibited PAS-positive basement membrane material. Necropsy revealed a morphologically similar tumor in the ipsilateral orbit and lung. On immunohistochemical examination, the intraocular tumor stained diffusely immunopositive for vimentin, S-100, and neuron-specific enolase and multifocally, sparsely immunopositive for cytokeratin AE1/AE3. The orbital and thoracic tumors stained positively for vimentin but negatively for cytokeratin AE1/AE3. There are few reports of canine metastatic iridociliary adenocarcinoma in the literature; this is the first with immunohistochemical analysis.

Iridociliary adenocarcinoma with oncocytic change in a dog

An intraocular mass lesion was found in the left eyeball in a spayed female Pembroke Welsh Corgi dog. The surgically resected left eyeball was pathologically examined. Histologically, the mass lesion consisted of proliferation of the atypical cuboidal or columnar epithelial cells, arranging in papillary, tubular or solid form. In addition, some neoplastic cells showed oncocytic change characterized as large oval cells with numerous eosinophilic intracytoplasmic granules. Cytoplasm of the oncocytic cells showed dark blue granules by phosphotungstic acid-hematoxylin stain. Immunohistochemically, the oncocytic cells were intensely positive for cytochrome C. Based on these findings, the ocular mass was diagnosed as iridociliary adenocarcinoma with oncocytic change. The findings indicate that the oncocytic changes of the neoplastic epithelial cells might be caused by mitochondrial accumulation.

Ocular glioneuroma with medulloepitheliomatous differentiation in a goldfish (Carassius auratus)

An intraocular mass in the left eye causing chronic severe exophthalmia in an adult female goldfish ( Carassius auratus) is described. The fish shared an aquarium with another goldfish found dead with gross and microscopic lesions consistent with mycobacteriosis. Histological examination of the left eye, histochemical (periodic acid–Schiff [PAS], Alcian blue, Ziehl–Neelsen) and immunohistochemical tests (glial fibrillary acidic protein, human neuronal protein, vimentin, and cytokeratin AE1/AE3) were carried out on the intraocular mass. Neoplastic cells forming an unencapsulated highly cellular proliferation partially covered by an intact corneal epithelium were stained with Alcian blue, which demonstrated an abundant hyaluronic acid–rich extracellular matrix. Multifocally, there were cyst-like dilatations bordered by neuroepithelial cells, which were PAS-positive. The complex neoplastic proliferation was composed of glial-like cells, neuronal-like cells (immunoreactive to glial fibrillary acidic protein and human neuronal protein, respectively) and neuroepithelium, which suggested a retinal origin.

Benign intraocular teratoid medulloepithelioma causing glaucoma in an 11-year-old Arabian mare

CASE DESCRIPTION

An 11-year-old Arabian mare was presented for investigation of a visible, pale-colored intraocular mass in the right eye.

CLINICAL FINDINGS

An intraocular mass was detected clinically and ultrasonographically as originating from the superior temporal quadrant of the ciliary body and iris and causing secondary glaucoma. The echodense mass was occupying the majority of the vitreous chamber and extended into the anterior chamber. The left eye appeared normal.

TREATMENT AND OUTCOME

Enucleation was recommended for therapeutic and diagnostic purposes. No adjuvant treatment was given. Histopathological examination demonstrated a benign intraocular teratoid medulloepithelioma located at the ciliary body. Immunohistochemical studies showed that neoplastic cells were positive for vimentin, S-100 protein, neuron-specific enolase (NSE), and nestin and negative for glial fibrillary acidic protein (GFAP). Electron microscopy revealed abundant cellular matrix and blood vessels surrounding tumor cells, which had indented, round to oval nuclei. There were also apoptotic bodies and cells containing melanosomes of variable shape and size. Eight years later, the horse has had no recurrence and maintains normal vision in the left eye.

CLINICAL RELEVANCE

This is the first report of a benign teratoid intraocular medulloepithelioma in an adult horse and the ultrastructural and immunohistochemical characterization of a teratoid medulloepithelioma in this species.

Immunohistochemical Characteristics of Normal Canine Eyes

Immunohistochemistry is widely utilized in diagnostic laboratories to study neoplastic and nonneoplastic diseases. Knowledge of the immunohistochemical characteristics of normal tissue is essential for interpretation of immunoreactivity in pathologic conditions. In this study, immunohistochemistry was performed with a broad panel of diagnostically relevant antibodies on 4 normal canine globes—namely, vimentin, pan-cytokeratin (AE1/AE3), cytokeratin 7, cytokeratin 8/18, cytokeratin 20, α–smooth muscle actin, muscle specific actin, desmin, Melan-A, microphthalmia transcription factor, S-100, glial fibrillary acidic protein, triple neurofilaments, neuron-specific enolase, chromogranin A, synaptophysin, laminin and CD31. Results include cytokeratin immunoreactivity limited to the conjunctival epithelium, corneal epithelium, and retinal pigment epithelium; distinct patterns of immunopositivity of muscle markers; and widespread immunoreactivity for vimentin and most neural/neuroendocrine markers. These findings in normal eyes provide the basis for interpretation of ocular immunohistochemistry in dogs. Published immunophenotypes of primary ocular neoplasms are also reviewed.

Bilateral intraocular malignant neuroectodermal tumors in a telescope goldfish (Carassius auratus)

Abstract A 5-year-old male telescope goldfish (Carassius auratus) developed buphthalmia of the left eye. An enucleation was performed and a diagnosis of a neuroectodermal tumor was made on histological examination. Although the fish initially recovered, it was killed 49 days postsurgery due to a severe decline in its condition. On histological evaluation of postmortem tissue samples, it was determined that the fish also had a neuroectodermal tumor of the right eye with local invasion of the brain. On immunohistochemistry, the neoplastic cells were positive for S-100. To the authors' knowledge, this is the first published case of naturally occurring bilateral intraocular neuroectodermal tumors in a fish.

Metastatic intraocular chondrosarcoma in a dog

Chondrosarcoma accounts for about 10% of all canine bone tumors and is the second most common primary bone tumor in dogs. In veterinary medicine, chondrosarcomas are classified as skeletal and extraskeletal. Extraskeletal chondrosarcomas are mesenchymal neoplasms of soft tissues and visceral organs that produce neoplastic chondrocytes in a fibrillary matrix. There is no involvement of bone or periosteal tissues in extraskeletal chondrosarcomas. The aim of this report is to describe the first case of a metastatic intraocular extraskeletal chondrosarcoma in a dog.