Exérese tumoral seguida de blefaroplastia no tratamento de carcinoma de células escamosas em pálpebra inferior de equino / Tumoral resection followed by blepharoplasty in squamous cell carcinoma treatment in the lower eyelid of a horse

Background: Equines are routinely subjected to enucleation due to palpebral tumors. Blepharoplasties in horses, especially in the lower eyelid, are rarely performed due to the difficulty of sliding once the tissue around the eyes presents low mobility. Defects involving more than 50% of the lower eyelid is considered challenging after tumor removal. Squamous cell carcinoma (SCC) is the second most reported neoplasm in horses, being very common in regions of the lower eyelid, third eyelid, sclera and or cornea. The aim of this study is to present the Destro VY skin advancement flap as a blepharoplasty technique performed after surgical excision of a SCC, with total commitment of the lower eyelid, completely covering the right eye of a mare. Case: A 8-year-old mare Paint Horse, weighing 420 kg, was referred for evaluation of tumor tissue of 6.0 x 4.0 x 2.0 cm, with nodular and ulcerated appearance, involving the right lower eyelid, in its total extension and completely covering the eye, without adhering to it. Considering the initial suspicion of SCC, the treatment strategy performed was surgical eyelid excision and maintenance of the eye, followed by blepharoplasty as an attempt to reconstruct the eyelid. Under general inhalation anesthesia, the animal was placed in left lateral recumbency, when the surgical region was prepared and local anesthetic block was performed. After antisepsis, a skin incision was made circumscribing the tumor, respecting a margin of 10 mm apart and excision of all visible tumor tissue was performed followed by intralesional ozone therapy. Blepharoplasty was performed to cover the portions of the exposed lacrimal and zygomatic bones, as well as correction of the eyelid aesthetics. For this, Destro VY skin advancement flap was performed for reconstruction of the lower eyelid. An incision of approximately 7 cm in Vshaped skin was performed, and the subcutaneous tissue under the V was dissected, maintaining a central pedicle, responsible for the vascularization of the flap, which was slid, approximately 20 mm, towards the eye. After obtaining the desired skin approximation, Y-suture was performed, covering the exposed bone and reconstructing the lower eyelid. In the postoperative period, local instillation of mitomycin eye drops and systemic meloxicam administration were instituted. The mare had her vision restored, presenting satisfactory morpho functional and aesthetic results and no tumor recurrence during 1-year of follow-up. Discussion: The repair of lower eyelid imperfections is challenging, especially when they have large defects, and there are no reports of performing the Destro VY skin advancement flap technique in horses for lower eyelid reconstruction. In this case, the importance of the blepharoplasty technique is emphasized, avoiding enucleation, preserving horse's vision and aesthetics. In addition, aiming to avoid tumor recurrence, especially if surgical safety margins can not be achieved, other complementary treatments should be associated, including intralesional ozone therapy, mitomycin, an antineoplastic chemotherapy drug, and meloxicam, a COX-2 selective, non-steroidal anti-inflammatory drug, as performed in this study. It is concluded that the use of the Destro VY skin advancement flap technique for reconstruction of the external lamella in cases of SCC in the lower eyelid of horses is a feasible technique, which preserves the animal's vision, as well as aesthetics. The safety margin in the surgical excision of the SCC and the association of complementary therapies in the resolution of the condition are important points also to be considered.

Hemitireoidectomia por carcinoma em equino / Equine carcinoma hemithyroidectomy

Background: In horses, the thyroid gland is located slightly caudal to the larynx and dorsolaterally between the third and sixth tracheal ring, adjacent to the thyroid, there are four small glands called parathyroid glands. In the clinical routine of horses, thyropathies are difficult to be diagnosed, as they have a silent evolution. Thyroid neoplasia is the most common finding in horses, usually unilateral and normally present in older animals. The present study reports a case of equine thyroid carcinoma and its systemic clinical effects, which was successfully treated by means of hemitieroidectomy. Case: A 12-year-old male mixed breed horse weighing 436 kg, was admitted to the Veterinary Medical Teaching Hospital of the FZEA/USP with the main complaint of volume increase in the right ventrolateral region of the neck, difficulty in swallowing, significant weight loss and weakness of the pelvic limbs. On inspection, there was an increase in volume in the topographic region of the thyroid gland and on palpation, there was a firm mass, with delimited edges, with a smooth, mobile surface, without increasing the temperature and without pain. The animal was sent for ultrasound examination, which revealed a delimited mass, with an apparent capsule around it, differentiated and disorganized cellularity with small hypoechoic points of liquid inside the structure, with no apparent vascularization inside the mass. These findings, associated with the anatomical location of the mass, were consistent with thyroid tissue. The clinical signs commonly observed in thyroid neoformations are respiratory stridor, decreased performance, difficulty in swallowing and suffocation. As there was a compromised diet and weight gain, as well as athletic performance, he chose to have a hemithyroidectomy. After surgery, histopathology of the tissue was performed and thyroid carcinoma was diagnosed. Postoperatively, the animal was medicated with antibiotics, anti-inflammatory and anti-tetanus serum, after 10 days the stitches were removed and the animal was discharged. Discussion: Neoplasia is the most frequent cause of progressive thyroid growth and in case of suspicion of thyroid disorders, thin needle aspiration (FNAB) is recommended and, later, histopathological examination, which is considered the gold standard for diagnosis pathologies of the thyroid gland. In the present case, no FNAB or preoperative histopathological examination was performed due to the time required to obtain the result, associated with difficulty in swallowing and significant weight loss, which required immediate removal of the mass. Considering that the ultrasound examination revealed the absence of noble structures or important vascularization very close to or adhered to the mass, its removal prior to the histopathological examination was indicated. As there was compromised feeding and weight gain, he opted for hemithyroidectomy, the recommended treatment for unilateral tumors in horses. When performing a hemithyroidectomy, it should be remembered that the parathyroid glands accompany the thyroid and are located in its posterior portion, in the pre tracheal region, with its variable final position. With this variation in topography, the identification of parathyroid glands becomes challenging and, consequently, after thyroidectomy, a portion of parathyroid glands stops operating, and this fact is marked clinically by hypocalcemia and its consequences. In this case described, in which the animal had a tumor in thyroid tissue, possibly the parathyroid functions were also altered, which probably reflected in the lameness in the pelvic limbs. It is concluded that partial hemithyroidectomy in horses is an easy procedure to perform and has favorable results in relation to prognosis and quality of life.