Ocular and multicentric lymphoma in a young racehorse

A 6-year-old thoroughbred gelding was presented with a history of blepharospasm and opacity in the OS of 1 weeks' duration. Ophthalmic examination findings were consistent with acute uveitis in the OS, and traditional treatment was initiated with systemic antibiotics and anti-inflammatory drugs, topical mydriatics, and corticosteroids. During the total treatment period of 4 weeks response to treatment was weak and the horse developed further problems such as cellulitis of the right hind limb with fever and eventually weight loss and dependent edema. Blood work was indicative of liver disease. Abdominal sonography revealed severe splenomegaly and slight hepatomegaly, and a liver biopsy confirmed malignant T-cell lymphoma. The horse was euthanized due to deteriorating general condition and subsequently underwent postmortem examination. Necropsy and histologic examination revealed a multicentric lymphoma with involvement of spleen, mesenteric lymph nodes, and OU.
The findings in this case demonstrate that the differential diagnosis of intraocular and systemic lymphoma should be considered in any horse presenting with anterior uveitis, especially when uveitis is unresponsive to treatment and when additional systemic signs of illness such as lethargy, fever, weight loss, or dependent edema arise.
Cytological examination of aqueous humor may provide a rapid diagnosis of intraocular lymphoma in eyes with clinical uveitis.     

POLYARTHROPATHY AND ANTERIOR UVEITIS AS PARANEOPLASTIC SYNDROMES IN A GUINEA PIG WITH DISSEMINATED LYMPHOMA

A 4-year-old, intact male guinea pig was presented for evaluation of ocular pain and forelimb lameness. Initial examination confirmed that the ocular pain was associated with bilateral anterior uveitis and that the lameness was attributed to a bilateral carpal and metacarpal polyarthropathy. Carpal joint taps revealed nonseptic marked mixed inflammation later confirmed as a nonerosive immune-mediated polyarthropathy. Treatment with topical steroid ophthalmic ointment resulted in rapid resolution of the uveitis; the arthropathy was initially managed with pain medication and anti-inflammatories, then later with doxycycline and cyclosporine. Over the course of 7 days, the joint swelling and pain improved slightly, but the patient developed severe exophthalmos of the right eye. An ocular ultrasound examination revealed a space occupying mass in the retrobulbar space and results of a fine needle aspirate of the mass was diagnosed as lymphoma. Treatment with prednisone was set to be initiated after a 3-day wash-out period of meloxicam, but the patient was euthanized before the initiation of chemotherapy. Necropsy results confirmed the lymphoma had infiltrated the right eye, kidneys, adrenal glands, thyroid glands, lungs, liver, spleen, testicular interstitium, urinary bladder, pancreas, mesentery, lymph nodes, and meninges. This is an unusual presentation of apparent paraneoplastic uveitis and immune-mediated polyarthropathy in a guinea pig.     

Management of bilateral uveitis in a Toxoplasma gondii-seropositive cat with histopathologic evidence of fungal panuveitis

A 5-year-old, neutered male Domestic Short-haired cat was referred with a 5-month history of anterior uveitis and cataract in the right eye. Clinical examination confirmed anterior uveitis and immature cataract in the right eye and chorioretinitis in the left eye. Ocular ultrasound showed a retinal detachment in the right eye. Diagnostic testing revealed elevated serum titers for Toxoplasma gondii. Anterior uveitis in the right eye and chorioretinitis in the left eye progressed, resulting in blindness despite a 21-day course of clindamycin and aggressive topical medical management of uveitis. The right eye was enucleated and histopathologic evaluation of the globe revealed panuveitis and multiple organisms morphologically consistent with Histoplasma capsulatum. Systemic treatment with itraconazole was initiated. Vision returned after 3 months of treatment and complete resolution of the retinal hemorrhages with formation of a flat chorioretinal scar was noted after 6 months of therapy. Itraconazole was discontinued 7 months after starting therapy, at which time the funduscopic appearance of the chorioretinal scar had remained static for 1 month. The cat has remained visual without evidence of disease progression for 6 months following discontinuation of itraconazole.     

PRIMARY INTRAOCULAR OSTEOSARCOMA WITH PULMONARY METASTASIS IN A GUINEA PIG (CAVIA PORCELLUS)

A 3-year-old male guinea pig (Cavia porcellus) presented to the UNAM Exotic Pet and Wildlife Teaching Hospital. Clinical signs included hyphema, buphthalmos, goniosynechiae, anterior uveitis, and hypopyon of the ventral iridocorneal angle of the right eye. The right globe was enucleated and submitted for histopathology and the histopathologic findings were consistent with osteosarcoma. Thoracic radiographs did not reveal evidence of other primary tumors or metastasis. Four months later, the patient had pleural friction rub sounds upon auscultation of the lung fields and prescapular lymphadenomegaly. Radiographic evaluation revealed a radiopaque mineral-dense structure in the right caudal pulmonary lobe, suggestive of osteosarcoma metastasis. The presumptive diagnosis was confirmed at necropsy. This is the first report of a primary intraocular osteosarcoma in a guinea pig.     

CASE REPORT: Amelanotic uveal cyst in a Yorkshire terrier dog

The diagnostic challenge presented by an amelanotic uveal cyst with an atypical appearance in a 9‐year‐old Yorkshire terrier dog is reported. The dog was presented with a peculiar cystic neoformation adherent to the edge of the pupil of the right eye. The cyst wall was attached to the pupillary margin and it was bean‐shaped, measuring approximately 4.5 × 2.5 mm. It was white in colour with several red striations and a small brown spot in the middle, which conferred on it a peculiar appearance. The cyst could not be transilluminated and partially impaired vision. Apart from that, the ophthalmic exam revealed no other abnormalities and the eye showed no signs of inflammation. Ocular ultrasound revealed the cystic nature of the neoformation. During paracentesis of the anterior chamber, the cyst was deflated and both the cyst wall and fluid were aspirated. The tissue obtained was sent for a histological examination and was considered as corresponding to a uveal cyst. The dog improved from the post‐operative uveitis without any complication and after 24 months of follow‐up showed no recurrences.     

Congenital ocular anomalies and ventricular septal defect in a dromedary camel (Camelus dromedarius).

A 5-wk-old female dromedary camel (Camelus dromedarius) was clinically diagnosed with bilateral corneal dermoids, incomplete congenital cataracts, a left persistent hyaloid artery (PHA), and a ventricular septal defect (VSD). The corneal dermoids were removed by lamellar keratectomy, and vision improved in the left eye. Thirteen months after dermoid surgery, the calf was presented for enlargement of the right eye. Glaucoma was confirmed in the right eye, and corneal fibrosis and cataract were noted in the left eye. Persistence of the VSD was confirmed by cardiac ultrasonography. The calf was euthanized, and necropsy findings confirmed VSD. Histopathologic examination revealed bilateral corneal thinning and fibrosis, cataracts with retrolental fibroplasia, and retinal dysplasia. Additional changes in the right globe were anterior segment dysgenesis, ruptured lens capsule, chronic phacoclastic uveitis, and retinal separation. The PHA was confirmed in the left eye.     

Thymoma in a dog with a part of granular cell proliferation and concurrent lymphoma cells

A 12-year-old male Shiba dog showed anemia and the swelling of systemic lymph nodes. X-ray and post mortal examinations revealed a anterior mediastinal mass. Histologically, the tumor mass consisted of four different elements; cord-like proliferation of cuboidal epithelial cells, tubular or cystic structures lined with ciliated epithelial cells, proliferation of large round-shaped epithelial cells with PAS-slightly positive granular cytoplasm, and diffuse proliferation of neoplastic lymphocytes. Epithelial cells in cord-like or cystic structures were strongly positive for cytokeratin. Granular or foamy cells were negative for all markers examined and had myelin-like bodies in the cytoplasm by electron microscopy. The neoplastic lymphocytes in the tumor mass were considered being derived from concurrent multicentric lymphoma. Based on these findings, the present case was diagnosed as thymoma with a part of granular cell proliferation and concurrent lymphoma cells.     

Bicavitary effusion in a horse with multicentric lymphoma

A 14-year-old Quarter Horse gelding presented for a 2-week history of increased respiratory rate, fever and weight loss. The referring veterinarian performed an ultrasonographic examination on the farm and considered a differential diagnosis of pleuritis and pleuropneumonia. On presentation, transtracheal wash showed suppurative septic inflammation with bacteria within macrophages. Thoracic ultrasonography showed increased hypoechoic fluid in the pleural and peritoneal cavities. Cytologic analysis of pleural and peritoneal fluids revealed lymphorrhagic effusion with atypical lymphocytes, suggestive of a lymphatic flow obstruction or lymphoma. Treatment consisted of drainage of the pleural fluid, anti-inflammatory agents, fluid therapy and antimicrobial therapy. Continued fluid accumulation in the thoracic cavity, tachypnoea, lack of response to pain medication and progressive lethargy resulted in the horse being subjected to euthanasia. At necropsy, bicavitary effusion was confirmed and histopathological diagnosis of multicentric lymphoma was made. Horses presenting with pleural effusion should also be evaluated for peritoneal effusion, as bicavitary effusion may indicate noninflammatory conditions such as neoplasia.     

Unicentric extranodal lymphoma of the upper eyelid conjunctiva in a dog

A case of conjunctival lymphoma in a 4-year-old Siberian husky is reported. A large red mass protruding from the conjunctiva of the upper eyelid of the right eye was present. Irritation, blepharospasm and epiphora were revealed on initial ophthalmic examination. After anti-inflammatory treatment, surgery was performed. Histologically, the mass consisted of large polygonal cells with a high nucleus to cytoplasm ratio, moderate amounts of slightly eosinophilic cytoplasm, pleomorphic nuclei with vesicular chromatin and prominent multiple nucleoli. Mitotic figures were frequent. Approximately 70% of the neoplastic cells were CD3 positive and CD79alpha negative. On the basis of histologic and immunohistochemical findings, a diagnosis of intermediate-grade, diffuse large-cell lymphoma with T-cell immunophenotype was made. The surgical area healed uneventfully and, although chemotherapy was not received, after 12 months the dog exhibited no recurrence. To the authors' knowledge, this is the first report of unicentric extranodal conjunctival lymphoma in a dog.     

Intermediate syndrome of chlorpyriphos toxicity (Polaris) in a caracal (Caracal caracal)

A 5-yr-old spayed female caracal (Caracal caracal) was presented with complaints of acute onset of mental dullness, ataxia, and ventroflexion of 24-hr duration. The animal's garden territory was sprayed a day earlier with an organophosphate (OP) insecticide (chlorpyriphos-methyl). The caracal was treated for OP toxicosis and mildly improved. It was discharged a day later at the owner's request, although clinical signs did not resolve. During the following week, the caracal was confined to prevent further toxin exposure but did not improve and was presented 8 days later with similar clinical signs. Serum butyril-cholinesterase activity was markedly low. The relatively long interval from OP exposure, along with the duration of clinical signs, suggested an intermediate syndrome of OP toxicity. The caracal was treated symptomatically and progressively improved. It was discharged after 8 days of hospitalization and made full recovery 30 days later. This is the first report of OP toxicity in a caracal, suspected to progress to an intermediate syndrome of OP poisoning.     

Ophthalmomyiasis interna anterior associated with Cuterebra spp in a cat

An 8-year-old domestic shorthair cat was examined for severe anterior uveitis of the right eye that was unresponsive to aggressive treatment with anti-inflammatory drugs and for a possible intraocular parasite or foreign body trapped within a large fibrin clot in the anterior chamber. Surgical exploration of a presumed entry site on the caudal aspect of the third eyelid led to keratotomy and removal of a larval parasite later identified as a first instar Cuterebra spp. Aggressive treatment with anti-inflammatory drugs was continued after surgery, and intraocular pressure was monitored closely to ensure that the cat did not develop glaucoma. Two weeks after surgery, the cat had vision in the affected eye, with resolving uveitis and a normal fundus. Six weeks after surgery, the uveitis continued to resolve; however, the cat did not have vision in the affected eye, and examination of the fundus revealed retinal atrophy. In contrast to the condition in humans, a Cuterebra spp larval infection within the eye of cats may cause not only an intense, acute inflammatory reaction, but also retinal degeneration and blindness despite prompt surgical removal.     

Monitoring of large B-cell lymphoma and T-zone lymphoma in a dog via flow cytometry

A 12-y-old, castrated male Pomeranian dog was presented because of mandibular lymph node (LN) enlargement. Physical examination and a complete blood count revealed generalized lymphadenopathy and moderate lymphocytosis. Fine-needle aspirate cytology revealed expansion of medium lymphocytes in the right mandibular LN and expansion of large lymphocytes in the left popliteal LN. Flow cytometry identified 2 aberrant lymphocyte populations in both LNs, namely a CD5+CD45− T-cell population, and a large CD21+ B-cell population. Flow cytometry of the peripheral blood revealed an identical population of aberrant CD45− T cells. The patient was diagnosed with concurrent T-zone lymphoma and leukemia, and B-cell lymphoma. Multi-agent chemotherapy was instituted, and serial clinical and flow cytometric analysis revealed complete remission of the neoplastic B cells, but persistence of the neoplastic T cells and persistent lymphadenopathy. This case affirms the diagnostic value of flow cytometry and reveals a unique limitation of the RECIST criteria.     

Ocular manifestations of a metastatic pulmonary adenocarcinoma in a cat

A primary pulmonary bronchogenic adenocarcinoma originating from an intramediastinal accessory lung was diagnosed in a 14.5-year-old cat. The cat had been admitted because of a cloudy right eye. Physical examination revealed a thin cat with severe iritis, aqueous flare, and a fibrin clot in the anterior chamber of the right eye. Right fundic examination revealed bullous retinal detachment superior to the optic disc. Euthanasia and necropsy were requested when FeLV test results were positive. Metastatic neoplastic cells similar to those of the primary tumor were detected in the choroid, ciliary body, and ciliary processes of the right eye. Ciliary and iridic stromal necrosis attributable to neoplastic embolization of uveal vessels had led to severe uveitis. Foci of metastasis were also in the heart, kidney, and cerebral meninges.     

PCR for antigen receptor rearrangement (PARR) clonality testing in a horse with a solitary retropharyngeal lymphoma

A 19-year-old Quarter Horse gelding was evaluated for respiratory distress and a rapidly enlarging retropharyngeal mass. Initial evaluation revealed severe respiratory distress, and a large, firm mass, visibly appreciable as 12 × 12 cm, in the left retropharyngeal and perilaryngeal region, with surrounding left and right retropharyngeal swelling. No significant abnormalities were present on complete blood count and serum biochemistry analyses. Endoscopy revealed severe pharyngeal collapse restricting airflow without gross abnormalities of the pharyngeal mucosa other than inflammation and irritation. A multilobular retropharyngeal mass, diffusely heterogeneous in echogenicity, was present adjacent to, but not occluding, the carotid artery as assessed by ultrasonography. Initial needle aspirate suggested lymphoma. Tissue biopsy and histopathology confirmed a round cell tumour. A temporary tracheotomy was performed to provide respiratory relief, and the horse was managed on oral antibiotics and anti-inflammatory medications while awaiting histopathological results. The decision was made to humanely euthanise the horse after biopsy results indicated lymphoma. Definitive diagnosis of T cell rich, large B cell lymphoma was made by combination of cytology, immunohistochemistry and molecular clonality PCR (PARR) testing. Lymphoma should be considered in horses with focal masses of the retropharyngeal region. Although treatment was not pursued, PARR testing was successful in this case and may be helpful for accurate characterisation of lymphoma in horses to more precisely determine prognosis and the most effective treatment plans, as it has been in human patients and small animals.     

Extranodal conjunctival Hodgkin's-like lymphoma in a cat

A seven-year-old female spayed Domestic Short-haired cat was brought for examination following a four-month history of conjunctivitis in the right eye. The superior palpebral conjunctiva was diffusely swollen and firm, displacing the right globe ventrally and preventing full closure of the eyelids. The right popliteal lymph node was enlarged as were several other peripheral lymph nodes. An incisional biopsy of the conjunctival swelling revealed a lymphoid neoplasm, the cellular make up of which suggested features of feline Hodgkin's-like lymphoma. Although the neoplasm was poorly responsive to standard chemotherapeutic protocols for lymphoma, radiation therapy rapidly reduced its size. Three years following the initial diagnosis, there has been no recurrence of the conjunctival neoplasm. To the authors' knowledge, there are no previous reports of extranodal or adnexal (conjunctiva, eyelid, orbit) Hodgkin's-like lymphoma in the veterinary literature.     

Anterior chamber to frontal sinus shunt for the diversion of aqueous humor: a pilot study in four normal dogs

Silicone tubing was used to divert aqueous humor from the anterior chamber of the right eye to the rostral compartment of the right frontal sinus in four clinically normal mixed-breed dogs. Biomicroscopic examination, and pneumoapplanation tonometry and tonography, completed for up to 18 weeks postoperatively, confirmed gonioimplant function in all four cases. The dogs were euthanized at 6, 8, 16 and 18 weeks postoperatively. Gonioimplant patency was further confirmed by postmortem examination of the globes, implants and frontal sinuses. Gross and light microscopic examinations revealed iridal attachments to the implant ( n  = 4), mild anterior uveitis ( n  = 3), anterior subcapsular cataracts ( n  = 4), and focal corneal ( n  = 3) and scleral ( n  = 3) scarring in the operated globes. Light microscopic examination of frontal sinus specimens revealed mild lymphocytic proliferation and fibrosis immediately adjacent to the implant entrance site. There were no bacteria detected on aerobic or anaerobic cultures of the frontal sinuses or light microscopic examination of the globes or frontal sinuses. Results indicate that the frontal sinus shunting of aqueous humor is a safe and effective means of extraorbital aqueous diversion with potential applicability in the management of glaucoma.     

Diagnosis and treatment of a primary splenic lymphoma in a mule

The case reported here describes a transthoracic approach for removal of a splenic lymphoma from a 5‐year‐old mule. Nine months prior to presentation at Iowa State University College of Veterinary Medicine (ISUCVM), abdominal ultrasound was performed as part of a work‐up to investigate the cause of lethargy, anorexia and anaemia. Ultrasound examination identified a haemoabdomen and multiple splenic masses. Transabdominal biopsies were collected for histopathological evaluation and lymphoma diagnosed. Based on a number of clinical and laboratory examinations there was a lack of support for multicentric involvement and all results suggested solitary splenic involvement. Surgical removal of the spleen was accomplished via a transthoracic approach without complications. Histopathology of the splenic masses revealed a B cell lymphoma. Bone marrow was collected during surgery and submitted for cytology and was found to contain a normal lymphoid population with no evidence of neoplastic cells. The mule was discharged from the hospital 11 days after surgery.