Banca de QUALIFICAÇÃO: MELISSA DE ARAUJO RODRIGUES

Frozen biopsy and histopathological examination 

to evaluate surgical margins in canine soft tissue sarcomas – retrospective study (2021-2024)

dog; histopathology; neoplasia; transsurgical

Soft tissue sarcomas are a heterogeneous group of malignant mesenchymal neoplasms, originating in connective tissues, which have similar clinical behavior and histopathological findings. They can present in different locations on the body, but the skin and subcutaneous tissue are the most common sites, representing 8 to 20% of neoplasms that affect this organ. One of the main forms of treatment for soft tissue sarcomas is surgical removal with wide margins. In general, soft tissue sarcomas are locally infiltrative and poorly metastatic. Compromised histological margins are one of the main factors for the occurrence of tumor recurrences, which contributes to a decrease in the patient's quality of life and survival. Freeze biopsy is a technique in which a tissue sample is collected during surgery and is quickly frozen to preserve cellular and structural integrity. The sample is examined during surgery to identify the presence of cancer cells. This procedure is especially useful in oncological surgeries, as it helps in making decisions regarding whether or not to remove additional tissue, especially in the excision of neoplasms. Frozen biopsy can reduce the patient's chances of reoperation and tumor recurrence, increasing therapeutic success in the first surgical procedure. In Brazil, frozen biopsy is not yet widely used in veterinary medicine centers. Therefore, the objectives of this work were to employ and record the number of frozen biopsies in surgeries for cutaneous soft tissue sarcomas in dogs, in cases occurring between the years 2021 and 2024. Data referring to 29 cases were compiled and the following factors were analyzed: sex, race, age, site of presentation, number of tumors per patient, histopathological grade of soft tissue sarcoma, mitotic index, margin status surgery, most suspected sarcoma subtype according to cell morphology, occurrence of local recurrence and whether the patient was alive or died during the study period. The preliminary results from the 29 dogs regarding sex were that 20 were females and 9 were males. Ages ranged from 5 years to 14 years, with an average age of 9.3 years. The most prevalent dog breeds were mixed breeds (SRD) with 41.3% (12/29) of cases, followed by the Golden Retriever with 10.3% (3/29), Labrador with 6.8% (2/ 29), German Spitz with 6.8% (2/29), French Bulldog with 6.8% (2/29) and finally representing 3.4% (1/29) each, are the Greyhound, Fox Paulistinha, Beagle, Rottweiler, Dachshund, Poodle, German Shepherd and Shi Tzu breeds. In relation to the number of tumors presented by each patient, only one animal presented two cutaneous nodules, the other 28 patients developed a single tumor presentation. The most frequently affected anatomical sites were the limbs, with the right thoracic limb being the most affected. Other sites of presentation observed were: left thoracic limb, right and left pelvic limbs, abdomen, chest, face, back and breast. For cases where there was no exact record of the anatomical location of origin, only the term ‘’skin’’ was used. The histopathological grading of soft tissue sarcomas was defined as grade 1 for 58.6% (17/29) of patients, grade 2 for 41.3% (12/29) and no case was classified as grade 3. IM ( Mitotic Index) ranged from 1 mitotic figure to 20 mitotic figures in CGA (High Power Field). In some cases, it was possible to suspect, according to cellular morphology, the subtype of soft tissue sarcoma, with perivascular sheath tumor being the most suspected in 17.2% (5/29) of cases, the second most suspected was fusocellular sarcoma with 13.7% (4/29), equal in third position are hemangiopericytoma and peripheral nerve sheath tumor with 6.8% (2/29) each and finally the myxosarcoma with 3.4% (1/29), in 51.7% (15/29) of cases it was not possible to suspect the tumor subtype solely through cell morphology. The evaluation of surgical margins during surgery resulted in 70.3% (19/29) free lateral and deep margins, 7.4% (2/29) narrow, 7.4% (2/29) compromised, 11.1 % (3/29) partially narrow (narrow free and deep lateral margins) and 3.7% (1/29) partially compromised (committed free and deep lateral margins). Of the 29 dogs participating in this study, two died from causes unrelated to oncological disease, both showed no signs of local tumor recurrence, one dog is still alive and has no clinical signs related to a history of soft tissue sarcoma. Surveys on these clinical aspects of the remaining individuals are ongoing.