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.

Renal transitional cell carcinoma with bilateral ocular metastasis in a cat.

Case summary A 4-year-old, spayed female, domestic shorthair cat was presented for evaluation due to a 4 day history of inappetence and lethargy. Physical examination revealed mild dehydration and blindness of the left eye. Abnormal imaging findings included a well-margined soft tissue mass with irregular central cavity located in the dorsal aspect of the caudal lung lobe. Cytological examination of the mass revealed chronic inflammation with hemorrhage. Tests for parasitic and fungal diseases were negative. Ophthalmic examination 17 days after the cat was initially presented revealed severe diffuse pathology of both retinas. Left renomegaly was noted 22 days after the initial presentation, and cytological examination of samples obtained from the right vitreous, left kidney and the pulmonary mass yielded atypical epithelial cells exhibiting malignant changes. Post-mortem examination following euthanasia revealed renal transitional cell carcinoma with metastasis to both eyes, lungs and skeletal muscle. Immunohistochemical evaluation of the neoplastic cells in the eye revealed moderate cytoplasmic reactivity for CK7. CK20 immunohistochemistry was negative. Relevance and novel information To the best of our knowledge, this is the first report of renal transitional cell carcinoma with ocular metastasis in a cat. In addition, this report describes immunohistochemistry results of transitional cell carcinoma in a cat using CK7 and CK20.

Fungal polymerase chain reaction testing in equine ulcerative keratitis.

OBJECTIVE: To assess the diagnostic utility of fungal polymerase chain reaction (PCR) in forty-three horses with naturally acquired corneal ulcers presenting to a private practice. METHODS: Routine evaluation of cytologic, histologic, and microbiologic samples was performed. Two PCR approaches were compared - generic and specific fungal nested PCR followed by sequencing and quantitative PCR (qPCR). PCRs were applied to pure control fungal cultures, corneal tissue from ulcerated eyes and in a subset of 9 horses, to swabs from contralateral normal eyes. RESULTS: The expected fungus was identified by nested PCR and qPCR in all control fungal cultures. In all fungal culture-positive affected eyes (10/43), one or more fungi were identified by nested PCR and 4/10 were positive by qPCR. In 6/10 animals, the same fungus was identified by nested PCR and culture. Of these 6, only three were positive by qPCR. Fungal agents were identified by morphology in 8/10 horses. Diagnosis of fungal keratitis was reserved for only those cases in which the same fungus could be identified by PCR, culture, and morphology (5 horses). In 33/43 culture-negative affected eyes and in 6/9 unaffected eyes, one or more fungi were identified by nested PCR in 26 samples and by qPCR in 2 samples. Apart from Aspergillus spp, similar fungi were identified in affected and control eyes. Most eyes harbored mixed bacterial and fungal agents. CONCLUSIONS: Nested PCR results confirmed all cytologically positive cases of fungal keratitis. Nested PCR identified a greater spectrum of agents than either culture or qPCR.

Complications from residual adnexal structures following enucleation in three dogs.

CASE DESCRIPTION: A 3-year-old neutered male Lhasa Apso (dog 1) was evaluated because of chronic swelling at an 8-month-old enucleation site, a 10-year-old spayed female Japanese Chin (dog 2) was evaluated because of chronic swelling at a 6-year-old enucleation site and chronic discharge from a 1-year-old enucleation site, and a 7-year-old spayed female Yorkshire Terrier (dog 3) was evaluated because of chronic discharge from a 3-month-old enucleation site. CLINICAL FINDINGS: In all dogs, surgical exploration revealed substantial retention of adnexal remnants within the original enucleation sites. Diagnoses of subcutaneous membrana nictitans inclusion cyst, orbital pneumatosis, and conjunctival mucocele were made in dogs 1, 2, and 3, respectively. TREATMENT AND OUTCOME: Following cyst excision, dog 1 received a short course of treatment with amoxicillin-clavulanic acid and deracoxib. There was no recurrence of clinical signs over a 2-month follow-up period. For dog 2, conjunctival tissue was excised, and the opening of the lower nasolacrimal canaliculus was cauterized. The patient received postoperative administration of deracoxib as well as orbifloxacin and clindamycin pending bacterial culture results, which were negative. There was no recurrence of clinical signs over an 8-month follow-up period. For dog 3, adnexal remnants were excised. The patient received postoperative administration of amoxicillin-clavulanic acid and meloxicam. There was no recurrence of clinical signs over a 6-month follow-up period. CLINICAL RELEVANCE: Findings in the dogs of this report highlight the need for complete removal of the ocular adnexa to minimize the risk of complications of enucleation in the long-term follow-up period.