A captive female capybara (Hydrochoerus hydrochaeris) of unknown age discharged a bloody mass from the vaginal region. A histopathology examination revealed the mass to be a reproductive leiomyosarcoma, and an ovariohysterectomy was performed. The histopathology examination confirmed that the excised tissue was a uterine leiomyosarcoma. The purpose of this report is to describe clinical history and histopathological diagnosis of leiomyosarcoma in capybaras. This report is novel because it describes the first diagnosis of uterine leiomyosarcoma in a capybara. Since clinical data about capybaras are rare, this case report will help to diagnosis and treat reproductive diseases of this species.

Purpose: Triple-negative breast cancer (TNBC) has been associated with worse prognosis, and biomarkers are needed to identify high-risk patients who may benefit from clinical trials or escalated treatment after completion of standard treatment. We aimed to assess whether the post-treatment neutrophil-to-lymphocyte ratio (NLR) can reflect patient prognosis and determine the follow-up period that can provide the most feasible data. Methods: In this retrospective analysis involving patients with TNBC, clinicopathological data, including those on peripheral complete blood cell count, were collected. The prognostic powers of serial NLRs obtained at baseline and after treatment completion were compared. Kaplan-Meier curves were generated to compare the overall survival (OS) and distant disease-free survival (DDFS). Results: In total, 210 patients were enrolled. Forty-three (20.5%) events were detected. Twothirds of the events (29/43) were related to breast cancer. Most recurrent breast cancer-related diseases (27/29) were detected within 5 years of the initial diagnosis. In contrast, half of the events due to secondary malignancies or non-breast-related diseases (7/14) occurred 5 years after the initial diagnosis. Comparison of the prognostic performance of NLRs at baseline and at 6, 12, and 24 months after treatment completion revealed the strongest prognostic performance at 6 months after treatment completion (area under the curve = 0.745). The high NLR group (NLR >2.47) showed worse OS (p = 0.006) and DDFS (p < 0.001) than low NLR group. Conclusion Elevated post-treatment NLR was significantly associated with worse survival in patients with TNBC. We believe that it can be a useful surrogate marker for identifying highrisk patients with TNBC.