Combined stromal smooth muscle tumour of endometrium: report of two cases

Endometrial stromal tumours account for < 10% of all mesenchymal uterine tumours. If smooth muscle differentiation comprises ≥30% of the tumour mass, the neoplasm is referred to as combined stromal smooth muscle tumour. We report here two cases of benign combined stromal smooth muscle tumour of endometrium, each discovered as an incidental finding in a hysterectomy specimen with a clinical diagnosis of fibroid uterus, where each of the two components- stromal and smooth muscle comprised more than 30% of the tumour. Although none of them showed features of malignancy. This report of two cases of benign combined stromal smooth muscle tumours of endometrium adds to the morphological spectrum of the endometrial mesenchymal tumours.