Clinicopathologic and recurrence characteristics of leiomyoma with bizarre nuclei, which is rare type of uterine smooth macule tumors.

OBJECTIVES: LBN is a rare variant of uterine smooth muscle tumors. Although LBN is a benign variant of leiomyoma, recurrent cases have been reported. In our study, we aimed to evaluate the clinicopathological features of LBN cases and to define the characteristics of recurrent cases. MATERIAL AND METHODS: Seventy-six cases with LBN identified in the final pathology were included in the study. The patients' physical examination findings, imaging reports, postoperative complications, and medical data related to recurrence, metastasis, disease-free survival, and overall survival after LBN diagnosis were retrospectively evaluated. An immunohistochemical evaluation of the cases was conducted. RESULTS: Average patient age: 42.3 years. Myomectomy: 46.1%; hysterectomy: 53.9%. Mean follow-up: 40.4 months. Recurrence: 2 cases (2.6%), both in the uterus and myomectomy group. Post-myomectomy pregnancies: 8 out of 35 cases (22.9%). Mitotic count: 2.7. ER positivity: 30%; PR positivity: 33.8%. Ki-67: negative in 56.6%, focal positivity in 42.1%, diffuse positivity in 1.3%. p16 positivity: 14.5%; p53 positivity: 22.4%. PHH3 distribution: various levels from 0/10 to 9/10 BBA. Both recurrences managed with myomectomy, identified as LBN recurrences. CONCLUSIONS: LBN is a rare type of uterine smooth muscle tumor with a low recurrence rate, primarily affecting women of reproductive age, making conservative treatments like myomectomy appropriate. However, concerns about morcellation remain. While immunohistochemistry markers and the mitotic index help differentiate between LBN and LMS, their effectiveness in predicting recurrence and prognosis in LBN is limited.