Journal of Veterinary and Applied Sciences

Abstract
Conjunctival malignant melanomas are rare but potentially devastating tumours that have the tendency to recur after surgical excision. This case report is on a conjunctival malignant melanoma in a 10-year old Boerboel dog with history of recurrence after two consecutive surgical excisions. The dog was presented at the Veterinary Teaching Hospital, University of Nigeria Nsukka, Nigeria with a large, ulcerated and pigmented growth that almost completely obliterated the left eye. Comprehensive physical examination was done and blood sample was collected from the dog for haematology. The haematological parameters were evaluated following standard procedures. The dog was anaesthetized with a combination of Atropine Sulphate (0.04mg/kg), Xylazine, (0.75mg/10kg) and Ketamine (10mg/kg). The neoplastic mass was surgically excised alongside contiguous conjunctival tissues. The excised mass was sliced and fixed in 10% neutral-buffered formalin and processed for histopathology. Results of the haematological evaluation showed that the red blood cell (RBC) count of the dog was lower than the reference value for the species, while the mean corpuscular volume, total white blood cell (WBC), neutrophil and lymphocyte counts were above the reference values for dogs. Grossly, the excised neoplastic mass weighed 56.8 g, and was spherical, nodular, pigmented and firm. Microscopically, sections of the excised neoplastic tissue showed bizarre melanocytes with each cell possessing one or more prominent nucleoli. There were marked anisocytosis and anisokaryosis, numerous mitotic figures/40× fields, and moderate deposition of melanin pigment. Conjunctival malignant melanoma was diagnosed based on the high mitotic index. Normal vision with the affected left eye was restored by day 10 post-surgery, within which period Penicillin-Streptomycin (1ml/25kg), Paracetamol (15mg/kg) and Vincristine (0.7mg/m²) therapies were administered. Recurrence was again reported 3 months post-surgical excision in spite of treatment with vincristine. Exenteration would have been recommended, but the case was lost to follow-up.

Keywords: Malignant melanoma; Conjunctiva; Boerboel dog; Haematology; Mitotic figures; Conjunctivectomy.

How to cite this article:
Anyogu DC, Eze CA, Ezema A, Okereke N, Nnaji TO and Udegbunam SO (2023). Conjunctival malignant melanoma in a 10-year old Boerboel dog: A Case Report. Journal of Veterinary and Applied Sciences, 13(2): 224 – 232.

*Correspondence: E-mail: davinson.anyogu@unn.edu.ng Phone: +2347036841871