Clinical and pathologic evaluation of chorioretinal lesions in wild owl species.

OBJECTIVE: Investigate histopathology and spectral-domain optical coherence tomography (OCT) imaging of wild owls with chorioretinitis and identify any potential correlation with an infectious etiology. MATERIALS AND METHODS: Ophthalmic examination and retinal OCT imaging were performed on fifteen great horned (Strix varia) and barred (Bubo virginianus) owls (30 eyes) with chorioretinitis and five owls with normal eyes (10 eyes). Testing to investigate the presence of potential infectious diseases included a complete blood count, biochemistry, protein electrophoresis, West Nile virus (WNV) plaque reduction neutralization test, Toxoplasma gondii modified direct agglutination test, WNV RT-PCR, and Avian Influenza RT-PCR. A necropsy was performed on all owls, including ocular histopathology. RESULTS: Fundus lesions included retinal detachment (7/15 owls), depigmented lesions (12/15), pigment clumping (8/15), and retinal tear (4/15). All birds were negative for WNV and Avian Influenza on RT-PCR. Of the owls with chorioretinitis, 3/15 were seropositive for WNV and 7/15 for T. gondii. Optical coherence tomography of 25/30 affected eyes revealed outer retinal lesions (19/25 eyes), retinal detachment (16/25), and retinal tears (3/25). Histopathological examination revealed outer nuclear layer atrophy (19/30 eyes), retinal detachment (18/30), retinal tears (7/30), suprachoroidal hemorrhage (12/30), scleral rupture (3/30), and ossicle fracture (3/30). CONCLUSIONS: Although 20% of birds were seropositive for WNV and 46.6% for T. gondii, histopathologic findings supported that the posterior segment lesions in the study group were likely due to blunt ocular trauma rather than an infectious etiology. The results of OCT imaging and histopathology documented retinal changes most consistent with blunt ocular trauma.

Ocular porcupine quilling in dogs: Gross, clinical and histopathologic findings in 17 cases (1986-2018).

The objectives of this retrospective study were to evaluate the histopathologic changes associated with porcupine ocular quill injuries in dogs, to discuss the various methods of quill detection when quills are not grossly visible, and to discuss the pathogenesis of delayed ocular quill injuries in dogs. Seventeen globes sustaining ocular quilling injuries from 17 dogs (1986-2018) were identified in the COPLOW archives and the gross and histologic changes tabulated and compared. All cases were dogs, with one whole globe submitted from each patient. Sixteen of 17 cases had known or suspected porcupine encounters in the weeks or years preceding enucleation. Histopathologic findings included retinal detachment, hyphema, cataract, granulomatous to pyogranulomatous inflammation (uveitis, endophthalmitis, panophthalmitis), lens capsule rupture, suppurative phakitis, scleral perforation, stromal keratitis, breaks in Descemet's membrane, preiridal fibrovascular membrane, anterior and posterior synechia, Schnabel's cavernous atrophy, and periorbital fibrosis. Quill-associated ocular trauma can have a significant deleterious effect on vision and result in enucleation. The time from initial quilling to the manifestation of ocular signs may be prolonged (weeks to years). Any dog presenting for ocular signs with a history of a previous porcupine encounter should be carefully checked for quill migration into the globe as the source of ocular disease. Quills may not be visible grossly, and ancillary imaging techniques can be utilized with various rates of success.

Atypical free-floating iridociliary pigmented epithelial cysts and secondary glaucoma in a caiman (Caiman latirostris).

We describe a case of chronic ocular trauma that resulted in fixed and free-floating, pigmented epithelial iridociliary cysts, inflammation, and secondary glaucoma in a caiman (Caiman latirostris). A 20- to 25-year-old male caiman was presented with phthisis bulbi in the right eye, and congested episcleral vessels, corneal leukoma, disorganized anterior chamber, multifocal anterior synechia, and elevated intraocular pressure in the left eye. Ocular ultrasound of the left eye revealed round structures dispersed in the anterior and posterior chambers and vitreous cavity. Bilateral enucleation was performed, and gross pathology of the left eye revealed multiple pigmented cysts attached to the iris and posterior corneal surface causing marked distortion of the anterior uvea, and free-floating in the vitreous cavity. Histopathology demonstrated heavily pigmented cystic structures of iridociliary epithelium origin carpeting the anterior segment surfaces and causing obstruction of the iridocorneal angles, leading to secondary glaucoma. To the authors' knowledge, this is the first report of iridociliary cysts in wildlife species.

Ocular anatomy and correlation with histopathologic findings in two common octopuses (Octopus vulgaris) and one giant Pacific octopus (Enteroctopus dofleini) diagnosed with inflammatory phakitis and retinitis.

PURPOSE: Review octopus ocular anatomy and describe the histopathologic findings in three octopuses diagnosed with phakitis and retinitis. ANIMALS: Two common octopuses (Octopus vulgaris) and one giant Pacific octopus (Enteroctopus dofleini) with a history of ophthalmic disease. METHODS: A literature search was performed for the ocular anatomy section. Both eyes from all three octopuses, and two control eyes, were submitted for histopathologic evaluation. Hematoxylin and eosin stain was used for standard histopathologic evaluation; GMS stain was used to screen for fungi, gram stain for bacteria; and Fite's acid fast stain for acid fast bacteria. RESULTS: Anatomically, the anterior chamber of the octopus has direct contact with ambient water due to an opening in the dorsal aspect of a pseudocornea. The octopus lens is divided into anterior and posterior segments. The anterior half is exposed to the environment through the opening into the anterior chamber. Neither part of the lens has a lens capsule. The retina is everted, unlike the inverted vertebrate retina, and consists of just two layers. Histopathology revealed inflammatory phakitis and retinitis of varying severity in all six eyes of the study animals. No intraocular infectious organisms were recognized but one common octopus eye had clusters of coccidian parasites, identified as Aggregata sp., in extraocular tissues and blood vessels. CONCLUSION: We describe inflammatory phakitis and retinitis in two species of octopuses. The underlying cause for the severe intraocular response may be direct intraocular infection, water quality, an ocular manifestation of a systemic disease, or natural senescence.

The relative importance of phylogeny and habitat in determining the presence and prominence of a granula iridica in hooved mammals.

PURPOSE: To investigate the relationship between phylogeny and amount of shade in a species' habitat regarding the presence or absence of an iridal granula iridica (GI) in a large sample of Artiodactyl and Perissodactyl clades and using online resources. METHODS: The Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) archives were searched for glass slide material from Artiodactyl (even-toed) and Perissodactyl (odd-toed) ungulates. The slides were examined, and the presence or absence of the GI was noted. The phylogenetic tree of the ungulate species was inferred using TimeTree (http://www.timetree.org), and the habitat data are derived from Animal Diversity Web (https://animaldiversity.org/). We assessed the probability of the presence of GI occurring given the amount of shade in a species' environment using phylogenetic logistic regression. RESULTS: Forty-eight artiodactyl species were able to be evaluated and tabulated. Nine perissodactyl species were able to be evaluated. The phylogenetic logistic regression showed that the probability of GI presence was lower in artiodactyl species that inhabited shaded environments (ßshaded  = -1.774). Arctiodacyl species inhabiting a nonshaded environment were slightly more probable to have the GI present (ßnonshaded  = 0.023), with species inhabitating ambiguously shaded environments having a high probability of GI presence (ßambiguous  = 2.214). CONCLUSIONS: Our results suggest that the GI may be a common morphological feature to shade the pupil in nonshaded environments, and, in its absence, increase the amount of light reaching the retina to improve vision in shaded environments for hooved mammals. Further research on the functional optics of the GI and studies that include additional ungulate species would further elucidate phylogenetic and ecological factors influencing the occurrence of GI in hooved mammals.

A clinicopathological study of 17 cases of ocular surface xanthogranuloma in dogs.

OBJECTIVE: To evaluate the clinical, histopathological, and immunohistochemical features of 17 cases of ocular surface xanthogranuloma (OSX) in dogs. METHODS: Archived records from the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) were searched for cases of canine OSX. Cases were evaluated for lipid-laden macrophages and Touton giant cells. Seventeen cases matching those criteria were identified (1993-2018). Clinical and epidemiological data were collected from the submission forms and additional follow-up survey. RESULTS: Ocular surface xanthogranuloma in dogs presented as small bland nodules. OSX commonly occurred at the limbus (8/17) or cornea (4/17). Three of 17 affected animals were less than 1-year-old and the average age was 6.9 years (range 0.7-14 years). Fourteen of 17 cases did not report any lipid or metabolic abnormalities. Histologically, lesions were composed mainly of dense sheets of vacuolated lipid-laden macrophages and Touton giant cells with scant additional inflammatory cells and an intact overlying epithelium. No recurrence was noted in cases where complete surgical resection was achieved, and medical treatment either pre or post-resection led to only partial resolution. CONCLUSIONS: Xanthogranulomas are histiocytic lesions characterized by abundant lipid-laden macrophages. The authors use the term, ocular surface xanthogranuloma, to describe nodules with rigidly defined cellular characteristics. Although these lesions share characteristics with human limbal xanthogranulomas, further investigation is needed to suggest the different subsets that have been reported in the medical literature. Complete surgical excision is the most effective treatment for OSX in dogs, and intralesional triamcinolone and topical steroids can be useful adjunctive therapies to surgery.

Clinical and histopathological classification of feline intraocular lymphoma.

This retrospective study aimed to describe and classify cats with intraocular lymphoma, determine the proportion of cases with presumed solitary ocular lymphoma (PSOL) compared with ocular manifestations of multicentric disease and assess the clinical outcomes of these patients. One hundred seventy-two cases identified through biopsy submissions were reviewed histologically; 163 of these cases were subtyped according to the WHO classification system. Cases were categorized as having PSOL or ocular lymphoma with suspected systemic involvement (SSI) based on submission forms and follow-up data. The majority of cases exhibited concurrent uveitis (75%) and secondary glaucoma (58%). Diffuse large B-cell lymphoma was the most common subtype (n = 86; 53%), followed by peripheral T-cell lymphoma (n = 44; 27%). Other subtypes included anaplastic large T- (n = 8; 5%) and B-cell (n = 4; 2.5%) lymphomas, and 15 cases (9%) were negative for all immunohistochemical markers. In sixty-nine cases (40%), adequate clinical data and sufficient survival data were obtained to distinguish PSOL from SSI. PSOL comprised the majority of cases (64%), while 36% had SSI. When covarying for age at diagnosis, the median survival time was significantly higher (P = 0.003) for cases of PSOL (154 days) versus those with SSI (69 days); hazards ratio of 0.47 for PSOL (95% CI: 0.241-0.937). The subtype of lymphoma did not affect survival time. Cats with PSOL represent a greater proportion of the disease population, and this subset of cats with intraocular lymphoma has a better clinical outcome.

Management of corneal epithelial defects in a population of mature chuck-will's-widows (Antrostomus carolinensis) in South Florida.

PURPOSE: To describe ocular clinical findings, gross/histopathologic findings, and treatment regimens in a series of migratory chuck-will's-widows (Antrostomus carolinensis) (CWW) with corneal epithelial defects. METHODS: Seven CWW were presented to the South Florida Wildlife Center (SFWC). Four presented with bilateral (OU) corneal ulceration; two developed corneal ulceration OU; one had no ocular lesions. Treatment protocols for patients with corneal ulcers included the following: medical therapy only or medical therapy combined with an additional procedure. Four patients including the bird with no ocular lesions were euthanized, and one patient died. Their globes were submitted for histopathology. Two patients were released. RESULTS: Clinical findings prior to enucleation included superficial corneal ulceration with redundant epithelium persisting weeks to >1 month. On histopathology, epithelium in nonulcerated globes was remarkably thin; this was considered normal. Common histopathologic findings of ulcerated globes revealed epithelial and conjunctival attenuation with an acellular superficial stromal layer and hypercellular mid-stromal layer. One globe healed with medical therapy and cotton tip applicator debridement. Four globes healed by combination of medical therapy, equine amnion, nictitating membrane (NM) flap, and temporary tarsorrhaphy. No globes healed with diamond burr debridement or grid keratotomy. CONCLUSIONS: Factors that may be contributing to these corneal epithelial defects include, but are not limited to, normally thin epithelium, exposure keratopathy, neurotrophic disease, epithelial turnover and inadequate stem cell recruitment, inherited/genetic causes, and unidentified infectious agents (eg, viral etiologies). Of the 12 eyes treated, one healed with medical therapy/cotton tip applicator debridement, and four healed with medical therapy/equine amnion/nictitating membrane flap/temporary tarsorrhaphy.

A Transient Developmental Background Finding in the Retina Observed in Neonatal Dogs in Juvenile Toxicology Studies.

In a juvenile toxicology program, an unexpected finding of vacuolation of inner nuclear, ganglion cell, and nerve fiber layers of the retina was observed microscopically in routine Davidson's fixed and hematoxylin and eosin-stained tissue sections of eyes in beagle dogs at approximately 5 weeks of age. There was no necrosis or degeneration of the affected cells and no associated inflammation. Fluorescein angiography revealed no vascular leakage. Optical coherence tomography (OCT) indicated swollen cells in the same layers of the retina as observed at light microscopic examination. Transmission electron microscopy revealed that the retinal vacuolation likely was consistent with intracellular swelling of amacrine, horizontal, and/or bipolar cells of the inner nuclear layer as affected cells had an expanded cytoplasm but contained normal nucleus and organelles. As assessed by animal behavior and full-field electroretinography, the retinal vacuolation appeared to have no impact on visual function. Retinal vacuolation was seen in approximately 40% of dogs at 5 weeks of age using OCT and/or light microscopic examination. Because the change was transient and age related, did not result in degenerative retinal changes, and was not present in dogs older than 5 weeks of age, it was considered a background developmental observation in beagle dogs.

Feline Neovascular Vitreoretinopathy and Anterior Segment Dysgenesis With Concurrent Glaucoma in Domestic Cats.

Feline neovascular vitreoretinopathy (FNV) is a newly recognized rare condition affecting kittens and young domestic cats. This study investigated the clinical and pathologic findings in 22 cats with FNV. In affected cats, ophthalmoscopy of the fundus (when visible) revealed avascular peripheral retinae and epiretinal vascular membranes. Frequent nonspecific clinical findings were buphthalmos ( n = 21), medically uncontrollable glaucoma ( n = 22), and lenticular abnormalities ( n = 13). Anterior segment dysgenesis (ASD) was detected clinically in affected cats ( n = 6). The fellow eye was affected in 11 of 18 cats to a variable degree or appeared clinically normal in 7 of 18 cats. The globes were examined histologically and using immunohistochemistry for vimentin, glial fibrillary acidic protein (GFAP), synaptophysin, neurofilament, laminin, factor VIII-related antigen (FVIII-RA), and smooth muscle actin (SMA). Histologically, diagnostic features included laminin-positive epiretinal vascular membranes affecting the central retina, with an avascular peripheral retina and gliosis. Enucleated globes exhibited multiple additional abnormalities, including corneal disease ( n = 15), anterior segment dysgenesis ( n = 21), lymphoplasmacytic anterior uveitis ( n = 19), peripheral anterior synechiae ( n = 20), retinal degeneration ( n = 22), and retinal detachment ( n = 19). Gliotic retinae labeled strongly for GFAP and vimentin with reduced expression of synaptophysin and neurofilament, consistent with degeneration or lack of differentiation. While an avascular peripheral retina and epiretinal fibrovascular membranes are also salient features of retinopathy of prematurity, there is no evidence to support hyperoxic damage in cats with FNV. The cause remains unknown.

Canine, feline, and equine corneal vascular neoplasia: A retrospective study (2007-2015).

Corneal vascular neoplasms (hemangioma and hemangiosarcoma) are rare in all species. Reported cases are single case reports in a single species. Archived cases of corneal hemangioma and hemangiosarcoma from dogs, cats, and horses were obtained from the Comparative Ocular Pathology Lab of Wisconsin (COPLOW, Madison, WI), tabulated, and examined. This retrospective study describes the breeds, ages, tumor types, and characteristics of vascular neoplasms that appeared to be primarily corneal in location, in feline, canine, and equine patients, with gross and histologic images. There is a discussion of predisposing factors and speculated association with chronic ocular surface disease.

Iridociliary cysts masquerading as neoplasia in cats: a morphologic review of 14 cases.

OBJECTIVE: To report 14 neoplasia-free feline eyes enucleated for suspected intraocular neoplasia containing only iridociliary cysts. To analyze clinical findings that may have led veterinarians to suspect neoplasia in these globes. PROCEDURES: The archives at the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) were searched to identify neoplasia-free feline globes enucleated for suspected neoplasia. Clinical data were obtained from medical records, veterinarian surveys, and COPLOW submission forms. All samples were examined grossly and histologically. RESULTS: All eyes were free of neoplasia and contained one or more iridociliary cysts. Nine of 14 globes were enucleated by or based on the recommendation of a board-certified veterinary ophthalmologist. In eight of 14 cases, the submitting clinician listed melanoma as the only suspected diagnosis; in six of 14 cases, 'tumor' or 'mass' was listed. Clinical examination revealed a darkly pigmented intraocular mass in 11 of 14 cases. The mass was clinically perceived to be within the iris in seven of 14 cases. When examined histologically, 11 of 14 eyes contained multiple cysts, 13 of 14 contained multiloculated cysts, eight of 14 had a hyperplastic iris pigmented epithelium or cysts with thick black walls, and five of 14 had cysts prolapsed into the anterior chamber. CONCLUSIONS: Although most iridociliary cysts in cats are easily diagnosed on clinical examination, a subset may be mistaken for neoplasia. In cases of suspected iris melanoma, iridociliary cysts should be considered as a differential diagnosis, especially if a mass appears to emanate from behind the iris, dyscoria is present, or if similar changes are noted in the contralateral eye.

Ocular anatomy of the black pacu (Colossoma macropomum): gross, histologic, and diagnostic imaging.

OBJECTIVE: To describe the ocular anatomy of the black pacu (Colossoma macropomum), a freshwater teleost fish of the Amazon River basin, including an unusual choroid laden with adipose tissue. PROCEDURES: Three adult black pacu were anesthetized and examined clinically and with ocular ultrasonography, then euthanized. Three fish were euthanized and their heads imaged immediately postmortem using computed tomography. One fish was euthanized and its exenterated eyes imaged by high-resolution magnetic resonance imaging. The exenterated eyes of all seven fish were fixed in formalin; eyes from three fish were examined grossly and histologically. Additionally, archived histologic sections from two smaller black pacu specimens were examined. RESULTS: Findings were consistent among the ocular imaging modalities used. Intrinsic to the sclera were circumferential ossicles and scleral cartilage. The lens was spherical and protruded through the ovoid pupil with an aphakic space inferiorly when the accommodative mechanism was relaxed under anesthesia. Both a small falciform process and epiretinal vasculature were present in the posterior segment. The retina was cone-rich, and processes of the retinal pigment epithelium enveloped the photoreceptor outer segments. Remarkably, the choroid occupied one-third of the anteroposterior length of the globe; histology confirmed that the bulk of the choroid was composed of adipose tissue. CONCLUSIONS: The eye of the pacu overall is typical of teleosts but has the notable and consistent finding of a substantive store of choroidal fat of unknown function.

Lipoidal corneal degeneration in aged falcons.

OBJECTIVE: To present a case series of idiopathic lipoidal corneal degeneration in falcons. ANIMALS STUDIED: Five falcons including three peregrine falcons (Falco peregrinus), one prairie falcon (Falco mexicanus), and one red-naped shaheen (Falco peregrinus babylonicus) were observed to develop slowly progressive corneal opacification that began at the temporal limbus and extended centripetally across the cornea over a period of years. Four of the birds were over 20 years old. PROCEDURES: All animals underwent complete ophthalmic examinations. A red-naped shaheen underwent ocular imaging via spectral-domain optical coherence tomography. Two peregrine falcons were euthanized due to declining health, and their eyes were examined histologically. RESULTS: The opacities were pale and granular, with frequent vascularization associated perilimbally. Diffuse neutral lipid was observed in stromal cells throughout the corneal stroma of both clear and opaque areas of the cornea, sparing only the acellular anterior limiting lamina. Clusters of cholesterol crystals surrounded by macrophages were present in the mid-stroma. Fibrosis was evident in a subepithelial location, which separated the epithelium from the anterior limiting lamina. Ultrastructurally, diffuse vacuolization of the keratocytes was observed. No other ophthalmic or systemic abnormalities were noted. CONCLUSIONS: Results suggest that lipid degeneration occurs rarely in captive falcons of advanced age. The underlying cause is unclear. Though unsubstantiated, possible contributing factors include dyslipoproteinemia, corneal trauma, diet, and age-related alterations in corneal metabolism. The initiation of pathology at the temporal limbus, as well as slow progression, suggests that exposure contributes to the onset and progression of this unique keratopathy.

Canine and feline retinal lymphoma: a retrospective review of 12 cases.

This retrospective study identified 12 cases (6 canine and 6 feline) of ocular lymphoma with extensive retinal involvement and relative sparing of other ocular tissues. Our objectives were to describe the morphologic and immunohistochemical features of retinal lymphoma, assess the degree of correlation to the human counterpart, assign subtypes based on the veterinary-adapted WHO classification system, and promote accurate reporting of retinal involvement in cases of intraocular lymphoma. Our findings suggest that a distinct retinal tropism is quite rare, representing approximately 1% of all cases of canine and feline ocular lymphoma. No breed or sex predispositions were identified. The mean age of the affected animal was 7 years (range 4-10) and 11 years (range 6-19) for dogs and cats, respectively. Nine cases (5 canine and 4 feline) were classified as diffuse large B-cell lymphoma (DLBCL) subtype. The remaining cases were classified as peripheral T-cell lymphoma (PTCL).

The consequences of avian ocular trauma: histopathological evidence and implications of acute and chronic disease.

OBJECTIVE: To present a description and categorization of the histopathological lesions in avian ocular trauma. ANIMAL STUDIED: Seventy-five birds diagnosed with ocular trauma at to the Comparative Ocular Pathology Laboratory of Wisconsin. PROCEDURES: Histological slides were reviewed, and the type of trauma was classified by cause into either (i) blunt trauma or (ii) penetrating trauma and by duration into (i) acute or (ii) chronic. RESULTS: Blunt trauma was the most common source of trauma, and the most frequent lesions were observed in the retina (91%), with 71% of retinas having a tear or detachment and 46% of retinas showing chronic degenerative changes. Damage to the iris/ciliary body was present in 77% of cases. Corneal (17%) and lens (31%) lesions were relatively low. Acute traumatic events had a higher prevalence of readily identifiable discrete retinal tears/detachments (64%). Nearly all cases of chronic trauma exhibited chronic retinal lesions (93.7%), as well as a greater percentage of cartilage/bone lesions (71.4%), irido/cyclodialysis (51.9%), lenticular lesions (72.7%), and corneal damage (83.3%). However, the incidence of iridocyclodialysis was roughly equivalent for acute and chronic blunt trauma. CONCLUSIONS: Ocular trauma can lead to profound acute and chronic lesions within the eye. Here, we provide insight into understanding ocular damage caused by trauma, which may help future studies suggest new therapeutic options and provide insight regarding the releasability of avian wildlife.

Glaucoma with Descemet's membrane detachment in five horses.

PURPOSE: To describe the clinical and histopathologic features of glaucoma associated with Descemet's membrane (DM) detachment in five horses without prior history of intraocular surgery. ANIMALS STUDIED: Three Appaloosa horses and two Thoroughbreds were included in this study. The affected horses ranged in age from 16 to 27 years and presented with severe diffuse corneal edema. PROCEDURE: Five eyes were enucleated due to intraocular hypertension and/or chronic corneal ulceration. The enucleated globes were evaluated by the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW). Each globe was routinely processed for histopathology and analyzed by light microscopy. A histologic diagnosis of glaucoma was reached by demonstrating a loss of optic nerve axonal tissue by measuring neurofilament-immunopositive axons with automated image analysis software. RESULTS: All five horses presented with unilateral severe diffuse corneal edema that had developed between 2 and 16 weeks prior to enucleation. Intraocular pressures for the affected eyes were between 9 and 87 mmHg prior to enucleation. Descemet's membrane detachment was identified histopathologically in all five globes (5/5, 100%). All five eyes had an avascular spindle cell proliferation filling the space between the displaced peripheral DM and the corneal stroma. Neurofilament immunostaining revealed axonal loss consistent with glaucoma. CONCLUSION: Equine glaucoma may be associated with Descemet's membrane detachment. This detachment and glaucoma is a possible differential diagnosis for severe equine corneal edema. In this case series, an eye with a DM detachment had a poor prognosis for retention.

Short posterior ciliary artery anatomy in normal and acutely glaucomatous dogs.

OBJECTIVE: To quantify the total number and luminal areas of the short posterior ciliary arteries (SPCA) surrounding the canine optic nerve at the level of the sclera/lamina cribrosa in normal dogs and compare this data to dogs with a history of acute (≤7 days) glaucoma. PROCEDURES: Twelve normal globes were obtained through Harlan Laboratories, the UW-Madison School of Veterinary Medicine necropsy service and via enucleation submissions to the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW). Ten globes with a history of acute glaucoma were obtained from submissions to the COPLOW. Optic nerves were cross-sectioned in 20 micron steps, and five distinct levels were identified: the retinal nerve fiber layer; the retinal pigmented epithelium and neural canal opening; the choroid/pre-lamina; the sclera/lamina cribrosa; and the retro-lamina. At the level of the sclera/lamina cribrosa, SPCA profiles were counted and the luminal area was measured using Cell Sens software. Normal and glaucomatous globes were compared using ANOVA. RESULTS: Statistically significant smaller luminal areas and fewer numbers of arteries were recorded between normal and glaucomatous globes. CONCLUSIONS: The glaucomatous eyes in this study have SPCA with decreased lumina, suggestive of a vascular pathology present at the early stages of clinical glaucoma. Smaller lumina may be a contributing factor to the ischemia, necrosis, and the eventual full-thickness retinal atrophy often seen in glaucomatous dogs.

Third eyelid gland neoplasms of dogs and cats: a retrospective histopathologic study of 145 cases.

PURPOSE: To describe the various types of primary neoplasms affecting the third eyelid (TEL) gland of dogs and cats. METHODS: A retrospective search of the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) database was performed. Veterinary ophthalmologists, primary care veterinarians, and, when appropriate, owners were contacted for patient follow-up information. Patient data points collected included species, age, sex, breed, laterality, tumor type, surgical margins, recurrence, metastasis, and length of follow-up. RESULTS: A total of 127 canine and 18 feline cases met the inclusion criteria. The most common canine TEL gland tumor was adenocarcinoma (n = 108; 85.0%) followed by adenoma (n = 18; 14.2%) and squamous cell carcinoma (SCC) (n = 1; 0.8%). For canine cases with follow-up information available (n = 62), 8.1% had confirmed or suspected metastasis and 11.3% had confirmed or suspected local recurrence of disease. The most common feline TEL gland tumor was adenocarcinoma (n = 15; 83.3%) followed by SCC (n = 3; 16.7%). For feline cases with follow-up information available (n = 9), 40.0% had confirmed or suspected metastasis and 30.0% had confirmed or suspected local recurrence of disease. CONCLUSIONS: This study determined that adenocarcinoma was the most common third eyelid gland tumor in both dogs and cats. The overall survival times were less, and metastatic occurrence and recurrence rates appeared to be higher for feline tumors as compared to those diagnosed in dogs. This is the first report of SCC originating from glandular ductular epithelium.

Suspected malignant transformation of B lymphocytes in the equine cornea from immune-mediated keratitis.

OBJECTIVE: To describe clinical, in vivo confocal microscopic, histopathologic, polymerase chain reaction assay for antigen receptor rearrangement (PARR) and immunohistochemical features of a horse with suspected malignant transformation of corneal B lymphocytes in immune-mediated keratitis (IMMK) and to also report surgical management and adjunctive treatment including topical and radiation therapies. CASE DESCRIPTION: A 15-year-old Oldenburg gelding was examined for presumptive progressive stromal IMMK of the right eye which became refractory to medical management. Corneal in vivo confocal microscopy revealed a marked infiltration of neovascularization, leukocytes, and dendritic cells. Superficial keratectomy was performed. Histopathologic and immunohistopathologic abnormalities of the cornea were restricted to the anterior and mid-stroma and included sheets of medium-size atypical lymphocytes which stained positively for CD79a and CD20 and also demonstrated clonal rearrangements of immunoglobulin heavy chain 2 (IGH2) and 3 (IGH3) confirming B-cell lymphoma. Complete physical examination, complete blood count, serum chemistry, thoracic radiographs, and thoracic ultrasound were performed. No evidence of systemic metastasis was found. Adjunctive local therapy included topical dexamethasone, mitomycin C, and radiation therapy using electronic surface brachytherapy. Follow-up at 16 months revealed a lack of corneal infiltrate and progressive clearing of corneal fibrosis and superficial pigment. CONCLUSIONS: This case represents a unique presentation of primary corneal lymphoma in the horse. Tumor development was associated with chronic IMMK and chronic topical anti-inflammatory therapy. Surgical excision with adjunctive therapy using mitomycin C and electronic surface brachytherapy was well tolerated and considered curative. Future immunohistochemistry and PARR will be important in characterizing the IMMK syndrome and its variations.