Presumed primary ocular lymphangiosarcoma with metastasis in a miniature horse.

A 7-year-old, 153.0-kg American Miniature mare presented for evaluation of keratoconjunctivitis of the right eye (OD). A superior palpebral conjunctival mass and stromal keratitis were diagnosed. The incisional biopsy diagnosis was a presumptive corneal hemangiosarcoma. Transpalpebral enucleation was performed, and histopathologic evaluation confirmed angiosarcoma of the conjunctiva, cornea, and extraocular muscles. The horse developed progressive epistaxis and orbital swelling following surgery. A systemic workup was performed 3 months after enucleation, revealing regrowth within the orbit and marked cranial cervical lymphomegaly, suggestive of metastasis. Humane euthanasia was performed, and necropsy confirmed a locally invasive periorbital tumor with metastasis to the submandibular tissue, submandibular lymph node, and thoracic inlet. Histopathologic evaluation of necropsy specimens revealed polygonal to spindle neoplastic cells lining neoplastic vascular channels lacking erythrocytes. Immunohistochemically, the neoplastic cells labeled strongly positive for PROX-1, vimentin, CD-31, VEGF, weakly positive for factor VIII-related antigen, and negative for collagen IV. Based on the clinical, histological, and immunohistochemical features of this tumor, a primary ocular lymphangiosarcoma with metastasis was diagnosed.

Equine orbital fractures: a review of 18 cases (2006-2013).

OBJECTIVE: To review the clinical features, treatments, complications, and outcomes of horses with traumatic orbital fractures. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Eighteen horses with confirmed orbital fractures. PROCEDURES: Medical records of horses presenting with orbital fractures between 2006 and 2013 were reviewed. Signalment, etiology of fracture, clinical signs, fracture descriptions, diagnostic imaging, treatments, complications, and outcomes were evaluated. RESULTS: Eighteen horses presented with orbital fractures resulting from rearing in a confined space (n = 5), being kicked (4), colliding with a stationary object (3), and unknown trauma (6). Radiography and computed tomography were effective at classifying fractures and evaluating sinus/nasal involvement. Epistaxis/sinusitis were associated with fractures of the zygomatic process of the temporal bone (n = 3) and comminuted fractures of multiple bones (5). Seventeen fractures required treatment, with fifteen receiving a combination of medical and surgical therapy. Surgery included reduction of large bony fragments (n = 8), removal of small fragments (12), stabilization with a wire implant (1), and sinus trephination and lavage (5). Factors contributing to a favorable outcome included: globe retention (n = 16), vision (14), comfort (15), cosmesis (9), and return to previous function (13). CONCLUSIONS: Horses sustaining orbital fractures treated promptly with medical and surgical therapy have a favorable prognosis for return to function and cosmesis. Fractures affecting the zygomatic process of the frontal bone are unlikely to involve the sinus/nasal cavities. Epistaxis and sinusitis warrant more aggressive therapy and decrease functional and cosmetic outcome.

Treatment of immune-mediated keratitis in horses with episcleral silicone matrix cyclosporine delivery devices.

PURPOSE: To describe the use of episcleral silicone matrix cyclosporine (ESMC) drug delivery devices in horses with immune-mediated keratitis (IMMK) with evaluation of tolerability and efficacy in long-term control of inflammation. METHODS: Retrospective study. ESMC implants (1.2 cm length, 30% wt/wt cyclosporine (CsA) in silicone; with approximately 2 µg/day steady-state release for at least 400 days) were used. RESULTS: Nineteen horses (20 eyes) received two or more ESMC implants for superficial stromal (n = 9), midstromal (n = 3), or endothelial (n = 5) IMMK. Three additional horses received two or more ESMC implants for pigmentary keratouveitis (PK). Nine eyes of eight horses with superficial and five eyes of five horses with endothelial IMMK were well controlled after placement of ESMC implants (mean follow-up 176.8 and 207.2 days, respectively). Horses with midstromal IMMK and PK were not controlled with ESMC implants alone, but instead required frequent use of other medications or surgery to control the disease. The mean duration of disease prior to ESMC implantation of horses with midstromal IMMK was 495 ± 203.9 days, compared with 121.6 ± 92.7 days with superficial IMMK. ESMC implants were well tolerated by all horses without documented loss of the device. CONCLUSIONS: Results from this preliminary retrospective study suggest that the ESMC implants were well tolerated and associated with treatment success with superficial and endothelial IMMK, especially if placed early in the disease process. Further study is needed to determine the duration of efficacy, number of implants required, and better therapies for chronic midstromal IMMK and pigmentary keratouveitis.