Mast cell tumors (MCTs) are hematopoietic neoplasms composed of mast cells. It is highly common in dogs and is extremely important in the veterinary oncology field. It represents the third most common tumor subtype, and is the most common malignant skin tumor in dogs, corresponding to 11% of skin cancer cases. The objective of this critical review was to present the report of the 2nd Consensus meeting on the Diagnosis, Prognosis, and Treatment of Canine Cutaneous and Subcutaneous Mast Cell Tumors, which was organized by the Brazilian Association of Veterinary Oncology (ABROVET) in August 2021. The most recent information on cutaneous and subcutaneous mast cell tumors in dogs is presented and discussed.

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Canine cutaneous squamous cell carcinoma (cSCC) is the most common skin cancer in dogs, and, due to its low metastatic rate, local treatments, such as electrochemotherapy (ECT), promote disease control or even complete remission (CR). This study aimed to evaluate the gene and protein expression of Bcl-2 and Bcl-2 associated X protein (BAX), the proliferative index and clinical parameters in dogs with cSCC subjected to ECT. A prospective nonrandomized clinical study was performed using dogs with naturally occurring cSCC that was treated with ECT. Eighteen lesions from 11 dogs were selected. The tumor size at day 0 (D0) had no impact on survival or prognosis (P > 0.05). Tumor samples had a lower proliferative index after ECT (D21) than before ECT (P = 0.031). The survival of subjects with Ki67 values lower and higher than the Ki67 median value were not significantly different (P > 0.05). Regarding apoptotic markers, there were no significant differences in the gene and protein expression levels of BAX or Bcl-2 at D0 and D21 (P > 0.05) or in the overall survival of subjects with different levels of apoptotic markers. In conclusion, there was no change in BAX or Bcl-2 gene and protein expression in response to ECT at the time points evaluated, but ECT was able to reduce tumor volume and cellular proliferation in cSCC.

Fibropapillomatosis continues to be an important cause of morbidity and mortality in sea turtles, particularly in Chelonia mydas. Turtles with this debilitating herpesvirus disease usually present with multiple, large, and ulcerated cutaneous masses that compromise both locomotion and feeding. There are very few available therapeutic strategies, with surgical excision being the most common. However, this surgical excision is associated with a high rate of local disease recurrence and secondary infections. Electrochemotherapy has been used for the treatment of epithelial neoplasm in several animal species. This technique is based on a combination of chemotherapy, usually with bleomycin or cisplatin, and electroporation. It consists of a series of short, high-voltage electric pulses that lead to increased membrane permeability and more efficient transport of antineoplastic drugs through the cellular membrane. Here, two C. mydas fibropapillomas were treated with a standard electrochemotherapy protocol using intralesional bleomycin sulfate injections followed by the application of electric pulses. Two sessions were performed, with a 33-day interval between sessions. Complete regression of lesions occurred without side effects or complications in each animal. There was no sign of local recurrence, even 1 yr after the end of treatment. Electrochemotherapy may be an effective therapeutic alternative for sea turtles with fibropapillomas.

Background Ungual warts are considered the most common benign nail tumour, and they are caused by the human papillomavirus. Despite the numerous treatments reported in the medical literature, ungual warts are considered frustrating, with high relapse rates and a potential risk of nail dystrophy. Bleomycin is a therapeutic option showing a good safety profile and high cure rates. Objective To evaluate the efficacy of electrochemotherapy using intralesional bleomycin for the treatment of ungual warts in comparison with intralesional bleomycin alone and describe the side‐effects related to the use of both techniques. Methods This was a prospective, randomized, double‐blind, controlled clinical trial. Forty‐four 18‐ to 60‐year‐old female and male patients with ungual warts of only one finger were included. The patients were divided into two treatment groups: GA – intralesional bleomycin; and GB – electroporation and intralesional bleomycin. Following a single application, the patients were followed up for 180 days. Results The patients’ mean age was 36 years for GA and 37 years for GB. Most patients were female (68%). Of 22 patients in GA completing the study, 11 (50%) achieved the cure, while 18 (85.7%) of 21 patients completing the study in GB showed cure. A significant association of patients with or without cure after the GA and GB treatments (P = 0.022) was observed. None of the patients in either group had systemic side‐effects. Independent of the technique used, all the participants considered the adverse effects tolerable. Conclusion The intralesional use of bleomycin associated with electroporation for the treatment of ungual warts (both periungual and subungual) showed a statistically superior cure when compared with intralesional bleomycin alone. Side‐effects were more frequently observed in the electrochemotherapy with bleomycin group than in the bleomycin monotherapy group.