Abstract
Case Description—A 5-year-old female yellow-bellied slider (Trachemys scripta scripta) was referred for evaluation of a 2-month nonhealing ulcerated mass on the dorsal aspect of the neck.
Clinical Findings—The turtle was quiet, alert, and responsive, with a 2 × 1.5-cm ulcerated lesion on the neck. Signs of discomfort were observed during manipulation of the neck; no other abnormalities were detected during physical evaluation.
Treatment and Outcome—Following total body radiography and hematologic and serum biochemical analysis, the turtle was anesthetized and the mass was surgically removed. The excised tissue was submitted for histologic evaluation. A histopathologic diagnosis of squamous cell carcinoma (SCC) was made. Further surgical revision was not an option because of the extensive nature of the lesion; therefore, the tumor bed was treated with electrochemotherapy (ECT). Two sessions of ECT were performed with a 2-week interval between treatments. Electrochemotherapy involved intratumoral administration of bleomycin followed by trains of biphasic electric pulses. The treatment was well tolerated, and the turtle was disease free after 12 months.
Clinical Relevance—ECT resulted in good local control of SCC and should be considered as a possible postsurgical adjuvant treatment in reptiles with cutaneous tumors.
A 5-year-old female yellow-bellied slider (Trachemys scripta scripta) was referred for evaluation of a nonhealing ulcerated proliferation on the dorsal aspect of the neck. The referring veterinarian had treated the lesion by topical administration of antimicrobials on the suspicion of an infection. The turtle was quiet, alert, and responsive and had a body weight of 274 g (0.6 lb) with a partially healed ulcerated lesion on the dorsal aspect of the neck (Figure 1). Because of the extensive nature and location of the lesion, it was removed en bloc rather than by performing a biopsy. The turtle was evaluated for general health with a CBC, serum biochemical profile, and urinalysis. Blood samples were obtained by venipuncture of the right jugular vein, in accordance with recommendations in the literature for reptiles.1,2 White blood cells were counted on a hemocytometer.2 The WBC differential count was determined by microscopic examination of a blood smear that was stained with modified Romanowsky stain.3,a Total body radiography was performed. On hematologic evaluation, mild anemia (PCV, 24%; reference range, 25 to 33%) and leukocytosis (WBC count, 40 × 103 WBCs/μL; reference range, 3.5 × 103 WBCs/μL to 25 × 103 WBCs/μL) that included heterophilia (heterophil count, 32 × 103 heterophils/μL; reference range, 0.95 × 103 heterophils/L to 14 × 103 heterophils/μL) and eosinophilia (eosinophil count, 6.4 × 103 eosinophils/μL; reference range, 0.17 × 103 eosinophils/μL to 5.90 × 103 eosinophils/μL) was found. No abnormal findings were found on urinalysis or whole-body radiography.
Diagnostic images of a 5-year-old female yellow-bellied slider (Trachemys scripta scripta) referred for evaluation of a 2-month nonhealing ulcerated mass on the dorsal aspect of the neck. A—Photograph of the dorsal aspect of the neck. Notice the 2 almost confluent ulcerating proliferative masses (diameter, approx 1.3 cm). B—Photomicrograph of a section of the lesion. Notice the areas of invasive growth with disruption of the basement membrane and extension into the underlying tissue (asterisks). H&E stain; bar = 100 μm. C—Photograph demonstrating application of caliper electrodes to the proliferative mass. Electric pulses are delivered through the caliper electrodes that are connected to an electroporator as a means of making the lesional cell membranes permeable for local treatment with bleomycin. D—Photograph of the dorsal aspect of the neck at the 1-year follow-up examination.
Citation: Journal of the American Veterinary Medical Association 246, 4; 10.2460/javma.246.4.455
The turtle was anesthetized with propofolb (10 mg/kg [4.5 mg/lb], IV), which was administered through the supravertebral sinus.4 The mass was excised to the margins and was submitted for histologic evaluation. Histologic sections of the mass were stained with H&E and Van Gieson stain. The turtle was hospitalized for 24 hours and received fluid therapy and antimicrobial treatment with enrofloxacinc (5 mg/kg [2.3 mg/lb], intracoelomic route, q 24 h).
The turtle was discharged from the hospital. The owner was instructed to continue administration of enrofloxacin for 9 days after discharge. Meloxicam (0.5 mg/kg [0.23 mg/lb], PO, for 3 days) was prescribed for analgesia.
A histopathologic diagnosis of incompletely excised well-differentiated SCC was made. Histologic findings were characterized by squamous differentiation and invasive growth with disruption of the basement membrane (Figure 1). Options available to increase the chances of local tumor control included surgical revision, radiation therapy (modifying protocols available for use in reptiles),5 photodynamic therapy,6 laser therapy,7 or ECT.8,9 The owner elected ECT. The surgical scar and a 1-cm margin of unaffected tissue were injected with bleomycind at a concentration of 1 mg/mL (total volume, 1 mL). Five minutes after the injection of bleomycin, trains of 8 biphasic pulses at the voltage of 1,200 V/cm (frequency, 1 Hz) lasting 100 microseconds (ie, biphasic pulse, 50 plus 50 microseconds) with eight 300-microsecond interpulses (total treatment time per cm, 3.2 milliseconds) were administered with a clinical electroporatore certified for veterinary use. The procedure was performed with the turtle under general anesthesia with propofol as previously described.4 The turtle did not develop any adverse effects to treatment and was discharged from the hospital. No abnormalities were found on a CBC that was performed at 1 week after the first ECT procedure. A second ECT procedure was performed 2 weeks after the first treatment. The turtle underwent recheck physical examination monthly for 3 months and then every 3 months, with total body radiographs obtained to check for possible metastatic spread. After 1 year, the turtle remained disease free with a good quality of life.
Discussion
Electrochemotherapy consists of intratumoral injections of chemotherapy (eg, cisplatin or bleomycin) followed by local delivery of electric pulses to potentiate drug uptake. The electric currents are applied in biphasic pulses and induce clustering of the transmembrane proteins, thus increasing drug delivery. Treatments are delivered in 1 or 2 weekly sessions.
Electrochemotherapy, a combination of high-voltage electric pulses and administration of an anticancer drug, has been demonstrated to be highly effective for the treatment of cutaneous and subcutaneous tumors regardless of histologic origin. Unique properties of ECT (eg, high specificity for targeting cancer cells, high degree of localization of treatment effect, and capacity for preserving the innate immune response and the structure of the extracellular matrix) are facilitating its clinical use. In the present report, bleomycin was chosen as the drug of choice for ECT because the procedure greatly increases its uptake into cancer cells; the dose of bleomycin was calculated according to published guidelines for ECT.8,9
Cutaneous SCC has been described in snakes, lizards, and turtles.10–12,f Cutaneous SCC has been more frequently reported in monitor lizards, especially in the skin of the face.f In snakes, cutaneous SCC is most commonly found in the cloacal region, originating from scent glands, hemipenis, or skin of the cloacal region. Cutaneous SCC is occasionally seen in turtles, and these tumors are well differentiated, are locally invasive, and invoke a scirrhous response; metastasis is generally rare.12 These tumor characteristics are consistent with those described for the turtle of the present report, which developed a single nonhealing ulcerated lesion that persisted for several months on the dorsal aspect of neck; histopathologic findings included a well-differentiated SCC. The extensive nature of the lesion prevented wide excision, resulting in incomplete tumor removal. Because of limited knowledge on the systemic administration of chemotherapeutics in chelonians, the turtle in the present report underwent local treatment with intratumoral injection of bleomycin. To further potentiate its efficacy, trains of electric pulses were administered to aid in making the lesional cells permeable for local treatment with bleomycin.9 Electrochemotherapy allowed for extended tumor control without adverse effects and with a good cosmetic appearance. Electrochemotherapy has proved to be an effective therapeutic strategy in veterinary oncology on different tumor types and animal species.8 In the turtle of the present report, ECT was effective without toxic effects. The short duration of the train of pulses administered also accounted for the limited morbidity observed in the turtle of the present report. In conclusion, ECT may be a reliable strategy for use in exotic animals as a postsurgical adjuvant treatment.
ABBREVIATIONS
| ECT | Electrochemotherapy |
| SCC | Squamous cell carcinoma |
MCG Quick Stain, Bio-Optika SpA, Milan, Italy.
Bleomicina Solfato, Sanofi Aventis, Milan, Italy.
Baytril injectable solution 5%, Bayer, Milan, Italy.
Propofol Kabi, Fresenius Kabi, Verona, Italy.
Onkodisruptor, Biopulse Srl, Naples, Italy.
Garner MM. Trends in reptilian neoplasia: a diagnostician's perspective (abstr), in Proceedings. 55th Annu Meet Am Coll Vet Pathol 39th Annu Meet Am Soc Clinic Pathol 2004;P1226.
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