Case description: An approximately 5-year-old sexually intact male alpaca was evaluated because of a right-sided maxillary mass that had recurred after previous surgical debulking.
Clinical findings: Clinical, radiographic, and CT examination revealed an approximately 1.5-cm-diameter soft tissue mass associated with expansile osteolysis of the maxillary alveolar bone, beginning at the level of the right maxillary third premolar tooth extending caudally to the level of the rostral roots of the second molar tooth.
Treatment and outcome: Right partial maxillectomy was performed, and histologic examination revealed an incompletely excised fibrosarcoma with osseous metaplasia. External beam radiation therapy to the tumor bed was initiated 1 month after surgery. Computerized planning was performed, and a total radiation dose of 48 Gy was prescribed in eleven 4.4-Gy fractions. Follow-up CT evaluations 6 and 58 weeks after radiation therapy was completed revealed no evidence of tumor recurrence. No clinical evidence of tumor recurrence was detected through 110 weeks after radiation therapy.
Clinical relevance: The oral fibrosarcoma in the alpaca described here was successfully treated with surgical excision and adjuvant radiation therapy, resulting in excellent quality of life of the treated animal.