A case report of uterine leiomyosarcoma: unusual clinical presentation with unilateral hydronephrosis and importance of an appropriate diagnosis.

Uterine leiomyosarcoma is a rare malignant gynecologic tumor that arises from the myometrial or endometrial stromal precursor cells. This tumor has the highest prevalence in the pre- and post-is more frequent between 40 and 60 years old. It has a very unfavorable prognosis: only early-stage tumors have an acceptable prognosis; unfortunately, it is often diagnosed accidentally, typically on an advanced stage, when hematological metastases have already spread. Surgery is the main treatment strategy, while systemic treatment and radiotherapy are not recommended due to the lack of results. Since metastatization is mainly hematological, lymphadenectomy is not recommended. Recent progresses have been achieved in advanced and recurrent disease, often inoperable, thanks to new chemotherapies, target therapies and immunotherapies. We reported the case of a 51-year-old woman evaluated for lumbar pain in the right region compatible with renal colic. The ultrasound evaluation revealed right hydronephrosis and the presence of a paraovarian or intraligamentary mass compatible with fibroma. The abdominal CT confirmed the presence of a mass with heterogeneous vascularization. Therefore, the patient underwent laparoscopic surgery to remove the lesion which resulted to be a leiomyosarcoma G2. During the following week the patient underwent a laparoscopic hysterectomy. The first step for differential diagnosis consists in the evaluation of clinicopathological features, followed by the analysis of preoperative imaging. Pelvic MRI represents the gold standard, while CT is used to detect metastases. The main issue is that imaging shows limited ability in differential diagnosis between benign and malign smooth muscle tumor. The definitive diagnosis is confirmed by histological analysis; this implies the necessity of improved attentions on the surgical procedure, which is often performed by steps with prolongation of the treatment pathway. To distinguish which fibroids presents a major risk to be misdiagnosed, some risk scores were developed (rPRESS in 2014 and pLMS in 2019), though actually they are not applied in clinical practice. Uterine leiomyosarcoma (uLMS) is rare but causes several deaths in perimenopausal women due to lack of effective treatments, although target therapies represent a future hope. Furthermore, clinical practice needs support through the development and improvement of diagnostic risk scores and their integration into guidelines.