Current Therapeutics and Future Perspectives to Ocular Melanocytic Neoplasms in Dogs and Cats

Adjuvant electrochemotherapy of malignant ocular melanoma in a dog

Melanocytoma and malignant melanoma are the most typical eye tumors in dogs and cats. Due to the presence of melanin, the general appearance is often highly pigmented in a nodular formation with well-defined borders. Electrochemotherapy (ECT) is a therapy combining reversible electroporation and anti-neoplastic drugs to enhance their cytotoxic effects through increasing cellular uptake by the electroporated tumor cells. In this article, the use of adjuvant ECT for the treatment of canine ocular melanoma is reported. The pre-surgical exams (blood count, renal and liver functions, echocardiogram, and electrocardiogram) were within the normal range, as were the chest radiography and abdominal ultrasound without signs of metastases. On the day of the surgery, an excisional biopsy of the tumor was performed without safety margins by keratectomy associated with conjunctivectomy and adjuvant ECT in the surgical site and peri-tumoral region. The animal was followed for approximately 7 months and remained without evidence of tumor recurrence. A complete resolution of corneal opacification was also observed. To our knowledge, this is the first report of the use of ECT in an ocular neoplasm. From a comparative oncology perspective, this report opens the way for future therapeutic approaches in superficial ocular cancers in veterinary and human medicine.

Iridial melanocytoma in a ferruginous hawk (Buteo regalis): A case report and review of avian melanocytic neoplasia

A 21-year-old, suspected female captive ferruginous hawk (Buteo regalis) was followed for 3 years due to an iridial mass of the left eye (OS) that progressively increased in size. Enucleation of OS was eventually recommended due to the iridial mass taking up approximately 75% of the anterior chamber, and the bird seemed less active. A complete physical examination, complete blood cell count, biochemistry, and survey radiographs were performed pre-surgery with no findings indicating metastasis. A subconjunctival enucleation was performed and the globe was submitted for histopathology through the Comparative Ocular Pathology Lab of Wisconsin. The histopathologic evaluation determined the mass to be consistent with an iris melanocytoma, which has not been previously reported in this species. The patient recovered well from surgery and has remained comfortable and active for 117 days post-surgery. This case report aimed to review the current available information on avian ocular neoplasms as well as describe the clinical presentation, medical management and surgical procedure, and long-term follow-up for this patient to enhance clinical understanding of the behavior of iris melanocytic tumors in avian species.

Mucocutaneous subdermal plexus flap for complete excision of a malignant dermal and conjunctival melanoma in a dog

PURPOSE

To perform a reconstructive blepharoplasty to obtain complete surgical excision of a darkly pigmented raised conjunctival-eyelid mass of the lower eyelid in a dog.

ANIMAL STUDIED

A 7-year-old, female-spayed, Yorkshire Terrier was evaluated for a slowly progressive, dark brown-to-black raised mass of the lower left eyelid. Sampling of the mass via fine-needle aspirate or incisional biopsy was declined, and an excision of the mass with the goal to obtain complete margins and maintain normal eyelid function with cosmesis was elected.

PROCEDURES

The lower palpebral conjunctival-eyelid pigmented mass was excised en bloc and the lower eyelid was reconstructed with a mucocutaneous subdermal plexus flap.

RESULTS

Histopathology revealed a malignant dermal and conjunctivalmelanoma excised with complete margins (1-2 mm). Short-term complications included corneal ulceration and eschar formation, which resolved completely at the 1-month follow-up. Long-term complications included mild trichiasis with epiphora and porphyrin staining. Tumor recurrence was not observed during an 8-month follow-up period.

CONCLUSIONS

The en bloc excision with mucocutaneous subdermal plexus flap was successful in obtaining complete surgical margins for a malignant conjunctival-eyelid melanoma. An excellent functional and cosmetic outcome was achieved without tumor recurrence during an 8-month follow-up period. A mucocutaneous subdermal plexus flap can be considered as a surgical option for malignant melanoma of the lower eyelid.

Bulbus Destruction by Choroidal Melanocytoma in a Dog: A 3-Year History

A 3-year-old male Slovak Hound with retinal detachment was presented. The causative intraocular mass was detected by ultrasonography, and the course of the disease was monitored over a 3-year period. Enucleation was performed due to secondary glaucoma. A benign choroidal melanocytoma was diagnosed by histopathology. To our knowledge, this is the first report that describes the disease over such a long period of time. The mild course of the disease questions enucleation of eyes with no or minor symptoms. Conventional treatment may be a suitable alternative to surgery for dogs with high anesthesia risks.