Leiomyoma is a benign tumor with smooth muscle origin, low frequency in domestic animals, and like the others neoplasias, rarely described in wild felids. The tumor may occur in a lot of organs like the uterus, gastrointestinal tract, gallbladder, and urinary bladder. Usually, this type of neoplasia is very proliferative, invading surrounding tissues. The main neoplasias that affect the uterus are carcinomas, adenomas, adenocarcinomas, fibromas, fibrosarcomas, leiomyomas, fibroleiomyomas, and fibro leiomyosarcomas, affecting usually adult animals. The objective of this paper was to describe the occurrence of leiomyoma in a captive puma (Puma concolor) in Brazil.
A puma (Puma concolor), female, of 15 years, born in captivity, resident with a male of the same species, presented mucopurulent secretion, intermittent for 15 days. The secretion was collected with a swab and examined in the optic microscope, where was visualized a high number of neutrophils. Then it was decided to restrain the animal with ketamine (10 mg/kg) and xylazine (1 mg/kg) and do a clinical exam. During the exam it was observed the presence of a soft structure in the abdomen. It was decided to do an exploratory laparotomy. There was a big, soft mass in the uterus and an ovariohysterectomy was performed. After the surgery, the animal was kept in a for pos surgical recuperation.
The uterus was carefully examined, and mucopurulent secretion was collected and kept in a Stuart medium for microbiology exam. Samples of altered and normal tissues were collected and kept in a 10% formalin solution for histopathologic and exams. The reagents used in the immunological exam were Vimectin, alpha actin, and Ki-67 antigen. The antigenic recuperation was done by humid heat using high pressure. The slides were examined in the optic microscope.
At the macroscopic evaluation it was possible to observe severe vessel congestion of the serosa and moderate enlargement of the uterus walls, presence of a big amount of yellow mucopurulent secretion and the presence of two masses in the uterine horns. One of the masses was localized in the medial part of the left uterine horns, approximately 12 cm in diameter, whitish-pink, firm consistency, and the presence of a cyst of 1.5 cm. The other mass was located in the right uterine horn and was 3 cm in diameter. Both of the masses were strongly adhered to the uterus wall and were projected into the uterine lumen without obstructing it. The ovaries were normal. In the histopathologic exam, it was observed the presence of exuberant production of mesenchymal tissue, showing multiples cellular bundles randomly. The tissue was composed of cells containing elongated nucleus, with discrete pleomorphism and rare stroma. The low irrigation of the masses resulted in extensive areas of necrosis. Although suggestive of leiomyoma in the histopathologic exam, it was decided to do an immunohistochemistry to find the origin of the neoplastic cells. The results of the alpha smooth muscle and the muscular actin antibodies characterized the tumor as a leiomyoma. The microbiological culture showed the presence of Bacillus brevis and Bacillus pasteurii. These agents are commonly found as contaminants or opportunistic in bacterial infections.
The most frequent neoplasias described in big cats in captivity are the carcinomas and the adenomas of the mammary gland. These tumors are usually related to the use of contraception substances. In this puma, it was diagnosed the presence of leiomyoma in the uterus wall. There was not found any report of uterus leiomyoma in big cats in captivity in Brazil, only the report of a leiomyosarcoma in mammary gland with metastasis in multiple organs in a captive jaguar (Panthera onca).