Surgery and electrochemotherapy for the treatment of cutaneous squamous cell carcinoma in a yellow-bellied slider (Trachemys scripta scripta)

• Autores: Andrea Lanza
• Localización: JAVMA: Journal of the American Veterinary Medical Association, ISSN-e 0003-1488, Vol. 246, Nº. 4, 2015, págs. 455-457
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • 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.

    View larger version(92K) Figure 1— 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.

    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.