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.     

Bilateral nodular lymphocytic conjunctivitis in a horse

A Russian jumper horse presented because of an ocular perilimbal conjunctival mass and, on clinical examination, two bilateral conjunctival masses were found, of different size and conformation. Attempts at complete excision of the left eye mass and excisional biopsy of the right eye mass were performed. The left eye mass recurred rapidly, but resolved completely after topical corticosteroid therapy. The two lesions had similar histopathologic features, characterized by focal, chronic, primarily lymphocytic conjunctivitis with follicular lymphoid hyperplasia. Special histopathologic staining techniques (Gomori methenamine silver and acid fast stains) and immunohistochemistry (for CD3, BLA36 and lysozyme) failed to reveal any etiologic agents and indicated an inflammatory lesion composed of a heterogeneous population of lymphocytes and macrophages (nodular lymphocytic conjunctivitis). The lesions were indistinguishable, clinically and behaviorally, from what has been reported as 'conjunctival pseudotumor' in the horse. Equine conjunctival pseudotumor/nodular lymphocytic conjunctivitis has been reported to be unilateral and have a good prognosis after partial or complete surgical excision. This is the first reported case of bilateral nodular lymphocytic conjunctivitis in a horse and for which surgical excision alone was not curative.     

Subconjunctival nodule due to Setaria equina erratic migration in a horse: First case report

An 18‐month‐old Arabian‐English filly resident in southwest France was referred for evaluation of a conjunctival mass in the right eye (OD). A pink, solid, and mobile nodular formation, measuring approximately 1.2 × 0.8 cm was found under the superior nasal bulbar conjunctiva during an ophthalmic examination that was otherwise normal. The mass was surgically removed using a standing procedure. Cytological examination of fine‐needle aspirates from the mass revealed a mixed eosinophilic‐lymphocytic inflammation. Histological examination confirmed the dense and diffuse eosinophilic‐lymphocytic infiltrate of the mass, and it revealed several cross sections of a parasitic nematode. The morphometric diagnosis identified an immature form of a filarial worm, and molecular analysis of the mitochondrial cytochrome c oxydase subunit 1 (cox1) and 12S rRNA gene sequences led to further identification of the specimen as Setaria equina. Microfilaremia was not observed on fresh blood smears. There have been no signs of local recurrence after 18 months, nor any evidence of intraocular involvement. To the authors’ knowledge, this is the first documented case of subconjunctival setariasis due to S equina in a horse.     

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.     

Neodymium:yttrium-aluminum-garnet laser-assisted excision of progressive ethmoid hematomas in horses: 20 cases (1986-1996)

OBJECTIVE: To describe a technique of contact neodymium:yttrium-aluminum-garnet (Nd:YAG) laser-assisted excision of progressive ethmoid hematoma (PEH) in horses, to determine the recurrence rate of clinical signs of PEH in horses with follow-up time of a minimum of 12 months, and to compare this result with reported results achieved by using conventional techniques. DESIGN: Retrospective study. ANIMALS: 21 horses with 26 PEH. PROCEDURE: Medical records of all horses with PEH treated by Nd:YAG laser excision from December 1986 through August 1996 were analyzed. Twenty-one horses underwent unilateral (18 surgeries) or bilateral (14) frontonasal bone flap with excision of the mass, using an Nd:YAG laser. One horse with bilateral PEH underwent a unilateral bone flap twice, 1 year apart. RESULTS: 1 horse died. Four of 20 horses with followup times of 12 months or longer had recurrence of PEH. The PEH recurrence rate was 20% (5/25 PEH). Three of 6 horses with bilateral lesions had recurrence of PEH. Recurrence rate for horses that had bilateral PEH (3/6 horses) was greater than for horses with unilateral PEH (1/14 horses). CLINICAL IMPLICATIONS: Treatment of PEH by Nd:YAG laser excision through a frontonasal bone flap results in a recurrence rate comparable with that reported for conventional techniques. Horses with bilateral lesions are more likely to have a recurrence of PEH.     

Primary lacrimal gland adenocarcinoma of the third eyelid in a horse

A 5-year-old Draft Horse gelding presented for evaluation of a large, fleshy, ulcerated third eyelid mass OD of 3 weeks duration. Complete ophthalmic examination, ocular ultrasound and skull radiographs revealed a large soft-tissue mass involving the entire third eyelid OD and extending into the ventral right orbit to the level of the globe equator. No other abnormalities were noted on physical or ophthalmic examination. Surgical removal via exenteration was performed 3 months after initial presentation. A lacrimal adenocarcinoma of the third eyelid was diagnosed based on histopathology. Concurrent asymptomatic intra-ductal and intra-acinar Demodex caballi parasites were found in the eyelid sebaceous glands, likely as an incidental finding. No tumor recurrence or metastasis has occurred 12 months after excision. To the author's knowledge, this case is the first reported primary lacrimal adenocarcinoma in a horse. Complete surgical excision was curative.     

Conjunctival malignant melanoma in a horse

A case of malignant melanoma originating from the conjunctiva of a horse is reported. The tumor exhibited locally aggressive behavior as evidenced clinically by recurrence following two treatment episodes including surgical excision on each occasion and one application of cryotherapy. The orbit was subsequently exenterated and histologically malignant conjunctival melanoma was confirmed. Histopathologic features included variable pigmentation with amelanotic sites demonstrating marked cellular and nuclear pleomorphism with high numbers of mitotic figures. Cords of neoplastic cells invaded the sclera and cornea. Following exenteration, the horse exhibited no recurrence of the tumor for five years before being lost to follow-up. To our knowledge, this is the first report of primary malignant conjunctival melanoma in a horse.     

Surgical management of orbital nodular granulomatous episcleritis in a dog

A 27 kg, 6‐year‐old, male castrated German shorthaired pointer presented to the University of Missouri, Veterinary Teaching Hospital with the complaint of progressive exophthalmia of 2 years duration optical density (OD). Lack of retropulsion OD was noted on physical examination. Anterior segment examination OU and fundic examination OS did not reveal any abnormalities. Examination of the fundus OD revealed focal scleral indentation of the inferior nasal globe. The indentation changed location with globe movement OD. MRI and CT scan revealed a well‐circumscribed, approximately 2 cm in diameter mass located caudal and ventral to the affected globe that appeared to communicate with the nictitating membrane with absence of any bony involvement. A modified lateral orbitotomy was recommended and performed to remove the orbital mass and nictitating membrane en‐bloc. Histopathology and immunohistochemistry of the mass confirmed a diagnosis of nodular granulomatous episcleritis (NGE). Postoperatively, the dog developed absolute keratoconjunctivitis sicca (KCS). Examples of primary episcleral inflammation in the dog include diffuse episcleritis, NGE, nodular fasciitis, fibrous histiocytoma, proliferative conjunctivitis/keratoconjunctivitis, pseudotumor, and Collie granuloma. The etiology of these episcleral inflammations is presumed to be immune mediated. To our knowledge, this is the first report of NGE affecting the orbital region of a dog. Development of absolute KCS resulting from excision of the nictitating membrane is also supported by this case.     

Treatment of hemangiopericytoma in a dog, using surgical excision, radiation, and a thoracic pedicle skin graft

A dog with hemangiopericytoma of the left forelimb underwent surgical excision followed by radiation therapy and thoracic pedicle skin grafting. Recurrence of the neoplasm was not observed 3.5 years after surgery. Hemangiopericytoma is an uncommon neoplasm that seldom metastasizes but has a high recurrence rate. In this dog, complete surgical excision was not possible because of the location and invasiveness of the neoplasm. The combination of surgery, radiotherapy, and skin grafting was a viable alternative to limb amputation.     

Use of a neodymium:yttrium-aluminum-garnet laser to remove exuberant granulation tissue from the esophagus of a horse

Use of a neodymium:yttrium-aluminum-garnet laser to remove exuberant granulation tissue from the esophagus of a horse A 4-year-old Quarter Horse mare was evaluated because of recurrent esophageal obstruction. Endoscopic examination revealed a proliferative mass in the esophagus approximately 55 cm aborad to the nares. Histologic examination of biopsy specimens revealed diffuse suppurative esophagitis and granulation tissue with no evidence of neoplasia. The mass was excisedand ablated transendoscopically with a neodymium:yttrium-aluminum-garnet laser. During a follow-up examination 2 weeks after the final laser procedure, the mass was no longer apparent, and the esophagus appeared healed. Six months after the final examination, there had been no recurrence of the mass. In this horse, transendoscopic laser excision was efficacious and avoided problems associated with an esophagotomy.     

Hemangiopericytoma in the eyelid of a horse

Hemangiopericytoma (HP) is a well-recognized neoplasm arising from vascular pericytes that has been reported only in the dog and man. In this study, we describe a 14-year-old female Arabian horse that was presented for surgical excision of a 2-cm-diameter expansile subcuticular mass in the right lower eyelid. Histologically, the mass consisted of loosely arranged interlacing streams and storiform bundles of spindle cells that often formed distinct whorls around a central capillary and bundles of collagen (Antoni A-like pattern). Immunohistochemical analysis revealed strong diffuse cytoplasmic immunoreactivity for vimentin and focal immunoreactivity for smooth muscle actin, whereas neoplastic cells did not stain for Factor VIII-related antigen, Glial fibrillary acidic protein (GFAP), or S100. On the basis of histomorphology and immunohistochemical reactivity, the present tumor was diagnosed as HP. To our knowledge, this is the first report describing a HP in a horse.     

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.     

Multicentric T‐cell lymphoma presenting as inferior palpebral swelling in a Standardbred mare

A 6‐year‐old Standardbred mare that presented with bilateral palpebral swelling and a left corneal ulcer was diagnosed with a multicentric T‐cell lymphoma. Other clinical findings included submandibular lymphadenopathy and oedema, pharyngeal oedema and rhinitis. Prior to euthanasia the horse developed keratomalacia, the onset of which was coincidental with the use of high doses of topical and systemic corticosteroids. Although an unusual presentation, palpebral swelling should be considered as a clinical sign of lymphoma.     

Unilateral orbital lacrimal gland abscess in a horse

A 20-year-old Thoroughbred gelding presented for evaluation of a periorbital dorsal swelling of the left eye that had been intermittently present for 3 months. Upon ocular examination, a firm, non-painful swelling was identified under the upper eyelid in the region of the orbital lacrimal gland, and was noted to extend anteriorly from underneath the dorsal orbital rim. Ultrasonographic examination revealed a mixed echogenic mass along the dorsal orbital rim that followed the contour of the globe. CT scan showed a moderately contrast enhancing mass that was contiguous with the eyelid. Differential diagnoses included neoplasia, inflammatory lesions such as a granuloma, foreign body or abscess. Surgical exploration and excision of the mass revealed a lobular structure with a purulent center. Histopathology identified the mass as the orbital lacrimal gland with concurrent severe dacryoadenitis. Culture of the purulent center of the mass revealed beta-hemolytic Staphylococcus aureus. The patient was maintained on supportive care and antibiotic treatment based on sensitivity postoperatively. No recurrence was reported 40 months later. This paper aims to identify bacterial dacryoadenitis as a cause for unilateral periorbital swelling in the horse. Differential diagnoses for this presentation, as well as successful surgical management are discussed. To the author's knowledge, this is the first case of bacterial dacryoadenitis and subsequent abscessation of the orbital lacrimal gland in the horse.     

Adrenal myelolipoma in a dog

Abdominal ultrasound examination in an 11-year-old, intact, female Labrador dog with hepatic disease revealed a nodular swelling of the left adrenal gland. Hyperadrenocorticism was suspected, but endocrine tests were negative. At the owner's request, an adrenalectomy was performed. Grossly, a nodular mass protruded from the external surface of the left adrenal gland and in cut section was hemorrhagic and effaced the cortical and medullary regions. Histologic examination revealed a cortical neoplasm with medullary involvement. The mass was composed of well-differentiated adipose cells, megakaryocytes, hematopoietic cells, and macrophages containing hemosiderin deposits. A diagnosis of cortical adrenal myelolipoma was made.     

Diagnostic imaging,surgical treatment and histopathological findings of a vascular hamartoma in a 2‐year‐old horse

We describe a case of a 2‐year‐old mare that presented with a large firm swelling on the lateral aspect of the right tarsus. Diagnostic ultrasound demonstrated a fluid filled cavernous mass that was not clearly demarcated from the surrounding subcutaneous tissue. Contrast radiography with intralesional injection of contrast medium showed accumulation of the medium in the caverns of the mass and in the saphenous vein. Contrast enhanced computed tomography demonstrated 2 vascular meshes, one deep and one more superficially, closely associated with the mass. Surgical excision of the mass was performed and a vascular hamartoma was diagnosed based on histopathology. The horse showed no signs of recurrence 7 months after surgery.     

Use of intralesional cisplatin to successfully treat distal limb haemangiosarcoma in a foal

A 4-month old, 200 kg, grey warmblood colt presented for a firm, non painful mass on the distal medial aspect of the left third metatarsus. Excisional biopsy revealed a diagnosis of haemangiosarcoma. Equine haemangiosarcoma is uncommon and only limited reports of successful treatment are available. The prognosis for survival is therefore considered to be poor. After two separate incidences of recurrence with incomplete excision of the tumour, intralesional treatment with cisplatin without excision or debulking was performed on three separate occasions. Intralesional cisplatin injection was performed at monthly intervals for three treatments. Four years post treatment with cisplatin, the horse remained in remission. This case report describes the diagnostic and treatment challenges for successful treatment of a primary haemangiosarcoma on the distal limb of a warmblood foal using intralesional cisplatin chemotherapy.     

Effects of treatment with and without adjuvant radiation therapy on recurrence of ocular and adnexal squamous cell carcinoma in horses: 157 cases (1985-2002)

OBJECTIVE: To determine the effects of treatment with and without adjuvant radiation therapy on recurrence of ocular and adnexal squamous cell carcinoma (SCC) at specific anatomic locations in horses. DESIGN: Retrospective study. ANIMALS: 91 horses. PROCEDURES: Medical records of horses with histologically confirmed ocular and adnexal SCC evaluated from 1985 to 2002 were reviewed. Sex, breed, age, type of treatment, location, and recurrence of SCC were recorded. Two treatment groups determined by recurrence of SCCs treated with and without adjuvant radiation therapy were established. RESULTS: The anatomic site with the highest recurrence rate was the limbus (junction of the cornea and sclera) or bulbar conjunctiva (477%), independent of treatment group. There was a significant difference in recurrence rates of ocular and adnexal SCCs between the 2 treatment groups, independent of anatomic location. Recurrence rates of SCCs treated with and without adjuvant radiation therapy were 11.9% and 44.1%, respectively. Recurrence rates for SCCs of the eyelid, limbus or bulbar conjunctiva, and cornea treated with adjuvant radiation therapy were significantly different from those for SCCs treated without adjuvant radiation therapy. The most frequently represented anatomic site for ocular and adnexal SCCs was the eyelid (28.7%). Coat color, breed, and the interaction of age and breed had a significant effect on tumor recurrence regardless of treatment type and anatomic location. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that ocular and adnexal SCCs treated with adjuvant radiation therapy had a significantly lower recurrence rate, compared with SCCs treated without adjuvant radiation therapy, independent of anatomic location.     

Adjuvant Electrochemotherapy Increases Local Control in a Recurring Equine Anal Melanoma

A 25-year-old gelding sport horse was referred for the treatment of recurring bilateral anal amelanotic melanoma. On physical examination, the horse presented bilateral poorly delimited perianal masses that recurred 2 months after surgical excision. The owner elected the lesions to be treated with surgery combined with electrochemotherapy using the drug cisplatin. The two masses were removed, and the surgical bed was treated with electrochemotherapy. A second session was performed 3 weeks later. The horse remained disease-free for 5 months and then experienced a marginal recurrence in one side. The nodule was re-treated, and the horse remained disease-free for 2 additional months, when it died of abdominal metastases. Electrochemotherapy can be added to the current strategies to palliate recurrent melanomas in horses.