Uterine Leiomyoma With Osteoclast-like Giant Cells.

Numerous histologic variants of uterine leiomyomas have been described. The main interest in recognizing these variants is differentiating them from leiomyosarcoma. Osteoclast-like giant cells (OLGC) have been described in association with leiomyosarcoma but to our knowledge, never with leiomyoma. We here report the case of a 58-year-old woman who underwent an elective total hysterectomy with bilateral salpingo-oophorectomy and bilateral pelvic lymphadenectomy for endometrial atypical complex hyperplasia. Multiple typical uterine leiomyoma were identified. One of them showed numerous OLGC admixed with fascicules of bland smooth muscle cells. No atypical features were identified in multiple sections of this otherwise classic uterine leiomyoma. The OLGC showed strong positivity for CD68. The patient, on follow-up, did not show any evidence of recurrent or metastatic disease. This unusual finding expands the morphologic spectrum of uterine leiomyomas. When confronted with a uterine smooth muscle cell tumor with an OLGC component, it is important to search for atypical features diagnostic of leiomyosarcoma.