RESUMO
Genital tumours are rare among cattle, largely due to their relatively short lifespans. Leio-myoma, a smooth muscle tumour being more prevalent in dogs, appears only at a rate of 1.00 - 2.00% in cattle, affecting reproductive efficiency in cases of complete uterine obstruction. This case report involves an 8-year-old cow with repeated insemination attempts unveiled 5.00 cm intra-luminal uterine mass, obstructing the right uterine horn. Transrectal sonography (TRUS) revealed a highly vascularized mass with normal ovarian function. Confirmation of clinical condition, i.e., uterine leiomyoma, via uterine biopsy concluded the presence of neoplastic smooth muscle cells arranged in interlacing bundles showing mild pleomorphism, and special staining using Masson's trichrome revealed an unappreciable amount of connective tissue; subsequently right flank celiotomy was performed to remove the benign tumour. Forty-five days after celiotomy, TRUS examination confirmed an unobstructed uterine horn, and bilateral oviduct patency was adjudged with 2.50% methylene blue. Following treatment for chronic endometritis, artificial insemination led to conception nearly 90 days post-procedure. The TRUS aids preliminary diagnosis, while definitive identification demands necropsy and surgical methods. This case underscores the diagnostic significance of TRUS, histopathology and celiotomy for identifying and managing uterine leiomyoma in cattle.