A clinicopathological study on uterine epithelioid leiomyoma

Objective To investigate the clinicopathological and biological features of uterine epithelioid leiomyoma(EL).Methods Two cases of uterine epithelioid leiomyoma were studied using clinical analysis,histopathology,immunohistochemistry and KRAS mutation detection with review of relevant literature.Results Both of the 2 tumours were composed of epithelioid cells with eosinophilic cytoplasm.One of them had huge size measuring 20×17×8 cm3 without necrosis and mitotic figures microscopically.Another was cellular measuring 2.5×2.1×1.8 cm3 without necrosis and showed epithelioid differentiation with mitotic figures(3-4/10HPF) microscopically.Immunohistochemical staining revealed that the tumour cells were positive for vimentin,desmin,actin,SMA,ER,PR and negative for CD10,MyoD1,S-100,HMB45,AE1/AE3,α-Inhibin,MDM2,p16,p53,CD117.The positive tumour cells of Ki-67 label index were both less than 2% in 2 cases.No KRAS point mutation was detected.Both patients showed no recurrence or metastasis until the last follow-up(18 months and 10 years respectively).Conclusions Uterine epithelioid leiomyoma was an uncommon neoplasm with uncertainly biological features.To clarify the diagnostic criteria and its biological features are most important for effective therapy and judging prognosis.