A case of lipogranulomatous conjunctivitis in a horse

Objective

To describe a case of lipogranulomatous conjunctivitis in a horse.

Animal Studied

A client-owned 12-year-old Standardbred gelding presenting with chronic conjunctivitis and palpebral masses.

Methods

Complete ophthalmic examination, surgical excision, histopathology, and bacterial culture of biopsy samples were performed.

Results

Upper and lower eyelids of both eyes were affected, with multiple yellow-to-white nodules on the palpebral conjunctiva, adjacent to the eyelid margin. Nodule removal was achieved via partial tarsal plate excision. Histopathological examination revealed granulomatous inflammation and large droplets of presumed free lipid in the conjunctival lamina propria. The animal was diagnosed with lipogranulomatous conjunctivitis. No postoperative ocular discomfort was observed for months; however, 3 years later, new conjunctival nodules were noticed, requiring a second surgical procedure on three of the eyelids. Transient entropion in the left lower eyelid was observed 2 months after the second surgery, and no recurrence of conjunctival nodules was observed after 18 months of follow-up.

Conclusion

To our knowledge, this is the first report of lipogranulomatous conjunctivitis in horses.     

Bilateral leiomyoma in the testes of a horse

A 19‐year‐old Hackney pony was referred to a veterinary teaching hospital for further investigation of left‐sided scrotal enlargement. Both testes were normally positioned within the scrotum and there was no pain on palpation. Ultrasonography revealed multiple masses of soft tissue echogenicity, located adjacent to the testicular parenchyma. They were hyperechoic when compared to the testicular parenchyma and affected both testes. Surgical excision was performed by closed castration. Gross examination revealed firm, white, nodular masses of varying size on the surface of both testes. The cut surface of individual masses had a dense, whorling, fibrous and somewhat shiny appearance. The histopathological diagnosis was bilateral, multicentric, well differentiated leiomyoma of the tunica albuginea. The smooth muscle origin was confirmed by immunohistochemical staining with an anti‐human monoclonal antibody reactive to smooth muscle actin. This is the first report of a bilateral, multicentric, leiomyoma in the testes of a horse confirmed by histopathology and immunohistochemistry. This case highlights that neoplasia should be considered as a differential for bilateral testicular enlargement.     

Equine conjunctival pseudotumors

Five horses presented with unilateral pink, smooth, nonulcerated conjunctival masses with histologic features characteristic of inflammatory pseudotumors, i.e. proliferative inflammatory lesions clinically resembling true neoplasia. Although causes for the inflammatory lesions were not determined, based on the presence histologically of mononuclear (predominantly lymphocytic) inflammatory cell infiltrates and the absence of infectious agents, parasites or foreign bodies, an immune-mediated pathogenesis was suspected. Affected horses ranged from 5 to 8 years of age with no apparent breed or sex predilection. Conjunctival lesions were nodular in two cases and relatively flat and more diffuse in three cases. Third eyelid lesions were present in three cases and two affected eyes had corneal involvement. Based on findings from these five cases, the prognosis for equine conjunctival pseudotumors appears to be good when lesions are treated by partial or complete surgical excision, local administration of anti-inflammatory agents, or a combination of surgery and anti-inflammatory therapy.     

Focal nodular hyperplasia in the livers of cynomolgus macaques (macaca fascicularis)

Two cases of spontaneous focal hepatic hyperplasia were observed in young female cynomolgus macaques (Macaca fascicularis). Grossly, a single raised nodule was observed in the left hepatic lobe. Histopathologically, the nodule compressed surrounding normal tissue; however, the hepatic cords within the nodule continued to those in the nor mal area except in part. Extensive fibrosis and absence of a normal hepatic triad were observed in the nodule. Thin fibrous septa radiating from the dense central stellate scarring and distended vessels were apparent in one animal. Hepatocytes in the nodule lacked cellular atypia, showed frequent PAS-positive eosinophilic inclusions in the cytoplasm and showed higher positive ratios for PCNA. The present cases resembled focal nodular hyperplasia reported in humans and a chimpanzee.     

Intravascular papillary endothelial hyperplasia of the conjunctiva in a horse

Objective Vascular tumors of the conjunctiva in the horse are rare. We present a unique case of an intravascular papillary endothelial hyperplasia of the conjunctiva. Animal studied Horse. Procedures Case report. A 6‐year‐old‐mare presented with a red mass in the conjunctiva of the left eye. After complete ophthalmologic examination the lesion was excised. The tissue was processed for light microscopy and studied histopathologically. Results Pathologic examination revealed a nonencapsulated vascular lesion composed of confluent vascular spaces filled by multiple papillary structures composed of a central collagenous core lined by hyperplastic endothelial cells. There was neither atypical endothelial cell nor mitotic activity. Conclusions Intravascular papillary endothelial hyperplasia is a benign proliferative lesion that should be differentiated from malignant vascular tumors.     

Laryngeal neuroendocrine tumour in a horse

A 13‐year‐old Quarter Horse mare was presented to the Ontario Veterinary College Teaching Hospital with chronic progressive respiratory noise and exercise intolerance. Severe respiratory stridor associated with a laryngeal mass was seen on upper airway endoscopy. Ultrasonography revealed an intra‐cartilagenous mass and allowed for a guided biopsy. Histological analysis of the mass characterised a neuroendocrine tumour and the mare was subjected to euthanasia due to the poor prognosis. Ultrasound examination was paramount in making the diagnosis and facilitating the biopsy. To our knowledge, neuroendocrine tumours have not previously been reported in the equine larynx.     

Retrobulbar dermoid cyst in a horse: a case report

A 4-year-old Andalusian horse was presented for examination following a 3-month history of exophthalmos of the right eye and a soft swelling of the right supraorbital fossa noted after blunt head trauma. Ultrasonographic examination of the swelling showed an anecogenic mass of 5 cm in diameter involving the retrobulbar space. Centesis of the mass through the supraorbital fossa was performed and yielded a serous fluid with 7.2 g/dL of total protein and density of 1040. No cells were seen in the sample. A tentative diagnosis of cyst was made. The cyst was surgically removed and the definitive histologic diagnosis was retrobulbar dermoid cyst. No recurrence has developed 18 months following the complete removal of the cyst capsule. To the authors' knowledge, there are no previous reports of retrobulbar dermoid cysts in horses. Localization, causes and success of surgical treatment of dermoid cysts are discussed.     

Bilateral third eyelid ectopic cilia in an adult horse

A 15‐year‐old Cob mare presented with a 4‐month history of chronic epiphora and intermittent blepharospasm in the right eye. On ophthalmic examination, two translucent aberrant hairs were identified at the third eyelid margin corresponding to an area of corneal fibrosis and neovascularization. Partial excision of the third eyelid was performed, and histopathology confirmed ectopic hair follicles. Two weeks later, clinical signs recurred in the same eye. Examination revealed another pair of aberrant hairs on the bulbar surface of the third eyelid near its leading edge. This portion of the third eyelid was also excised, and histopathology confirmed two additional ectopic hair follicles. Eight months later, the horse developed similar clinical signs in the left eye. Ophthalmic examination showed a single aberrant translucent hair at the third eyelid margin associated with focal fibrosis and neovascularization of the ventromedial cornea. Partial excision of the third eyelid was performed, and histopathology confirmed an ectopic hair follicle within the third eyelid conjunctiva. Excision was curative at 4 years postoperatively with no further recurrence in either eye.     

Successful treatment of a splenic abscess secondary to migrant metallic wires in a horse

This case report discusses a successful partial splenectomy for treatment of a splenic abscess in a horse. A 2-year-old Thoroughbred colt was hospitalised 5 weeks after an episode of severe colic that was followed by gradual weight loss and anorexia, pyrexia for 5 days and dehydration on the day of referral. A large splenic abscess was identified ultrasonographically. Following initial medical treatment, an exploratory laparotomy was performed. Multiple adhesions were released and a partial splenectomy conducted to remove the abscess. Migrant metallic wires penetrating from the small intestine into the splenic parenchyma were found to be the cause for the adhesions and the abscess. This paper summarises the potential advantages of utilising a partial vs. a total splenectomy and highlights the potential complications of these surgical procedure in equines.     

Periocular neurofibrosarcoma in a horse

A periocular neurofibrosarcoma was debulked and treated with intralesional cisplatin in a 5-year-old Thoroughbred mare. The horse presented with a 1-year history of a large slowly progressing subcutaneous mass over the right supraorbital process. The mass was surgically debulked, and intralesional cisplatin (1.0 mg/cm3) was injected in 3 doses at 2 weeks, 5 weeks, and 8 weeks postoperatively. No recurrence was noted over a 15-month follow-up period. Histopathology of the mass indicated neurofibrosarcoma.     

Oral doxycycline, niacinamide and prednisolone used to treat bilateral nodular granulomatous conjunctivitis of the third eyelid in an Australian Kelpie dog

A 5-year-old, female neutered, Australian Kelpie presented with a 2-month history of dramatic bilateral erythematous thickening of the third eyelids. Ophthalmic examination demonstrated raised, pink to red, irregular thickening of the entire palpebral surface of both third eyelids. There were no other ocular abnormalities. A surgical biopsy was taken from each third eyelid. Histopathologic examination revealed sheets of macrophages, plasma cells, lymphocytes, and occasional fibroblasts and neutrophils infiltrating the third eyelid stroma. A diagnosis of chronic granulomatous conjunctivitis was made. Grossly and histopathologically this case closely resembles previously described cases of nodular granulomatous conjunctivitis involving the third eyelids of Collie dogs. This report describes an unusual case of nodular granulomatous conjunctivitis isolated to the third eyelids in an Australian Kelpie. Resolution of the condition was achieved with a combination of oral doxycycline, niacinamide and prednisolone.     

Trunk deformation in the trotting horse

Reasons for performing study: Estimates of the position of the centres of mass (CM) of body segments are usually extrapolated relative to bony landmarks as determined in cadaver studies. This extrapolation assumes that segments are rigid bodies. Since the trunk represents a large percentage of the total body mass in horses, violation of the rigid body assumption by the trunk segment has important consequences for studying the biomechanics of equine locomotion. Objectives: To assess the magnitude of error in CM position due to deformability of the trunk segment and the timing of these errors during the trotting stride. The hypothesis was that shape changes during a stride are repeatable and predictable. Methods: Forty skin markers were attached in a grid pattern on the trunks of 6 adult horses, with an additional marker attached to each hoof. The markers were tracked using an 8 camera motion analysis system. Each horse was tested at 10 different velocities during trotting. The CM of the trunk was calculated under the assumption of a rigid body, based on 5 spine markers and from the volume encompassed by the 40 markers. The difference between the 2 calculation methods quantifies the effect of trunk deformation on the position of the CM. Results: The trunk changed shape during locomotion in a repeatable manner resulting in cyclic changes in CM position. Amplitudes of the CM displacement due to trunk deformation were equal in magnitude in the transverse and longitudinal directions. In the vertical direction, the CM moved only at half the amplitude. Magnitudes were strongly horse‐dependent. Conclusions and potential relevance: Shape changes in the equine trunk segment in the horizontal plane should be taken into account when modelling locomotion of horses. Amplitudes are horse dependent, complicating the development of correction routines.     

Surgical correction of aberrant conjunctival overgrowth in a rabbit: a case report

A dwarf rabbit presented with unilateral aberrant conjunctival growth. Allgoewer’s U-suture therapy was initially used to correct the overgrowth. Centrifugal incisions extending up to the limbus were made on the hypertrophic conjunctiva. Transpalpebral limbal fixation was performed next. When the symptoms recurred 3 weeks later, a second operation was performed using the Lembert suture method instead. The overgrowing membrane was excised radically just posterior to the limbus. The conjunctiva was then sutured using the Lembert pattern. The rabbit recovered with no further complications.     

Atypical thymoma in a horse: Diagnostic approach and application of an alternative histological classification system

Thymoma is a rare condition in horses. This case of a 24-year-old Warmblood gelding that was presented with oedema and signs of vascular congestion of the left forelimb caused by a thoracic mass is described. The diagnostic work-up included blood chemistry, cytology of pleural effusion, ultrasonography, radiography and the visualisation and collection of a tissue sample by thoracoscopy. Finally, post-mortem findings and histopathology revealed thymic epithelial neoplasia with histomorphologic features previously unreported in horses. The unique mixture of spindle-shaped and epithelioid tumour cells in combination with clear features of malignancy suggested the application of the Moran and Suster histological classification system for thymomas in humans (Moran and Suster, 2008, Curr. Treat. Options Oncol., 9, 288), which has not been reported in an equine case before and fits well to the present case.     

Bilateral Polydactyly in a foal

The following case report describes the diagnosis and surgery of bilateral polydactyly of unknown origin in a colt. A 7-month-old Berber colt was referred for cosmetic and curative excision of supernumerary digits. Radiographic examination revealed bilateral polydactyly and well-developed first carpal bones. Surgery consisted of an osteotomy of both second metacarpal bones combined with an amputation of the supernumerary digits. The follow-up at 18 months after surgery revealed a sound horse with an excellent cosmetic outcome.     

Standing low-field magnetic resonance imaging as a diagnostic modality for solar keratoma in a horse

A 22-year-old Friesian gelding was presented with a history of chronic, nonresolving lameness localised to the right front foot. Radiographs showed a smoothly marginated circular lucent area with a rim of increased opacity adjacent to the solar canal of the distal phalanx. The magnetic resonance imaging (MRI) revealed a reversed V-shaped smoothly demarcated space-occupying mass causing invagination of the solar laminae towards the solar canal arch and deformity of the adjacent surface of the distal phalanx. The mass was removed surgically and submitted for histopathology, which revealed a keratoma and periosteal fibrosis. Six weeks post-surgery the horse returned to the previous work level and 8 months follow-up showed no recurrence of keratoma. This report highlights the usefulness of MRI as a diagnostic modality for solar keratoma.     

Recurrent adnexal lymphoma in a horse

Lymphoma is a relatively uncommon neoplasm in the horse; however, it is considered the most common neoplasia of the equine haemolymphatic system. Limited reports of adnexal lymphoma have been documented in the literature, with no known reports of recurrence nearly a decade after mass excision. The objective is to describe a case of recurrent adnexal lymphoma in a 20-year-old Quarter Horse gelding presented to the Ophthalmology service at the University of Florida Veterinary Hospital (UFVH) for evaluation of a solitary subconjunctival mass of the right eye (OD). A focal, pink, fleshy mass associated with the dorsomedial bulbar conjunctiva was noted. An excisional biopsy was performed. Histopathology revealed lymphoma with clean margins. The client declined staging and further therapy at the initial visit. Approximately 8 years later, the horse began to exhibit intermittent mild to moderate diffuse swelling of the conjunctiva OD. Six months after onset, the swelling worsened acutely and was accompanied by severe swelling of the left conjunctiva (OS). The horse then returned to UFVH and was diagnosed with diffuse, bilateral conjunctival lymphoma. Humane euthanasia was elected. T cell lymphoma was confirmed with immunohistochemistry performed post-mortem. At necropsy, neoplastic tissue was observed throughout the adnexal and ocular tissues of both eyes and in the submandibular lymph nodes. Adnexal lymphoma is an uncommon neoplasm in the horse. To the authors’ knowledge, this is the first documentation of a nodular adnexal lymphoma that involved an 8-year period without recurrence followed by development of diffuse, bilateral disease. Typically, surgical excision of the nodular form of lymphoma involving the extraocular tissues yields an improved prognosis compared with the diffuse form of the disease. Further investigation is necessary to determine if nodular forms of adnexal lymphoma represent early stages of diffuse extraocular or systemic disease.     

Partial gastrectomy and total splenectomy for the treatment of a gastric mass in a horse

A 9-year-old cob mare with a history of recurrent colic presented during an acute colic episode. Ultrasonography revealed a mass emanating from the greater curvature of the stomach and was tightly adhered to the cranial edge of the spleen. Partial gastrectomy and total splenectomy were performed via a midline celiotomy incision. The mass was subsequently confirmed to be granulomatous inflammation, postulated to be secondary to a penetrating injury to the stomach. Post-operatively, the mare had episodes of recurrent colic that were successfully managed with optimisation of the horse's diet and feeding regime. At 10 months’ post-operatively the mare was managed on full turn out, with no evidence of colic and had returned to the previous level of ridden work. The horse then presented 14 months post-operatively with severe colic due to a large colon impaction and displacement and was euthanased. This is the first report to describe successful partial gastrectomy as a treatment option for a gastric mass in the horse.     

Periocular sarcoid in a horse

A periocular nodular sarcoid of the right upper and lower eyelids was diagnosed in an 11-year-old Thoroughbred mare. Computed tomography scan revealed the extent of the tumor. The mass was surgically debulked under general anesthesia, and the affected periocular region was injected intralesionally with Bacillus of Calmette and Guerin (BCG). An emulsion of cell wall fractions was used, which has been modified to reduce the toxic and allergic effect, but retain the antitumor activity. In total, five injections were performed at 2-week intervals. At follow-up 7 months after the last BCG injection, the tumor was completely resolved. Two years after the last treatment, the horse remains tumor-free.