Uterine leiomyosarcomas and leiomyomas: Two similar uterine solid tumors, totally different for prognosis

Abstract

The uterine leiomyosarcoma (LMS) is a rare sarcoma arising from the smooth muscle cells found within the myometrium, it is clinically aggressive smooth muscle malignancy, accounting for 2% to 6% of uterine malignancies and an annual incidence of 1.7 per 100,000 women. Although uterine malignancies such as endometrial cancer are common, uterine LMS accounts for only 1% of uterine cancers and is a part of uterine sarcomas' group, who comprises: carcinosarcoma (formerly known as MMMT, malignant mixed Mullerian tumor) (40% to 50%), leiomyosarcoma (30% to 40%) and endometrial stromal sarcoma (10% to 15%). Every group has its own risk factors, presenting symptoms, treatment response and prognosis.

Diagnosis challenges in a uterine leiomyosarcoma

“…As literature shows, the presence of necrosis associated with atypical mitotic activity suggest a reserved prognosis [8,17]. These histological characteristics also represent the main histological criteria for the diagnosis of uterine LMS [18], which also differentiate this malignant tumor from a leiomyoma or a STUMP [10].…”

“…The LMS histologic subtypes include epithelioid, myxoid, LMS with fusiform cells, and osteoclastic-like giant cells LMS [1], some of them histologically resembling either leiomyoma or degeneration subtypes [17]. Due to the large panel of uterine stromal tumors, the differential diagnosis was taken in consideration, to rule out a possible atypical infarcted leiomyoma (LM), a smooth muscle tumor of uncertain malignant potential (STUMP) ( Table 1), an endometrial stromal sarcoma, carcinosarcoma, or adenosarcoma (Table 1) In our case, the tumor presented spindle tumor cells, with hyperchromatic nuclei, exhibiting moderate to severe atypia, but without any particular histologic phenotype, as the above mentioned variants represent rare entities [3; 6].…”

Preoperative Magnetic Resonance Imaging Diagnostic Features of Uterine Leiomyosarcomas: A Systematic Review

“…Annual incidence is estimated to range from 0.5 to 7 in 100,000 women (15;17–20). The great majority of leiomyosarcomas are believed to arise de novo from the uterine myometrium or connective tissue surrounding the uterine vasculature, and very rarely, from pre-existing fibroids (18;21–25). Leiomyosarcomas are characterized by their aggressive behavior, with high recurrence rates once pelvic tissues are involved (18;19;24;26).…”