Objective: To investigate the clinical and pathomorphological features of multi-differentiated endometrial stromal sarcoma of the uterus and to discuss their behaviour and differential diagnosis.
Methods: The histological characteristics of all cases were observed by pathological examination, some of them have been studied by immunohistochemical and/or ultrastructural techniques.
Results: Multi-differentiation was present in 13 cases of low grade and 4 cases of high grade endometrial stromal sarcoma, of which, 13 cases had sex-cord differentiation, 10 cases had smooth muscle differentiation, osseous differentiation in 2 cases and striated muscle differentiation in 1 case. Two types of multi-differentiation was present in 9 cases.
Conclusions: Both low-grade and high-grade endometrial stromal sarcoma of uterus can display multi-differentiation. Sex-cord and smooth muscle differentiation are the most common types. Osseous and striated muscle differentiation are very rare. There is no definite correlation between prognosis and the amount or types of multi-differentiation components.