FINE-NEEDLE ASPIRATION CYTOLOGY OF LOW-GRADE ENDOMETRIAL STROMAL SARCOMAS

The cytomorphology of endometrial stromal sarcoma (ESS) has been descr ibed. However, almost all of the reports are about the high grade type according to the newly revised histopathologic criteria; the cytomorp hology of low grade ESS (endolymphatic: stromal myosis) has yet to be characterized. This paper reports on two cases of recurrent low grade ESS diagnosed by fine needle aspiration and confirmed histopathologica lly. The aspirates consisted of extremely cohesive tissue fragments of monotonous, small (8-9 mu m), oval cells tightly woven in a metachrom atic, extracellular matrix on Diff-Quik-stained smears. In Papanicolao u-stained smears the transparency allowed visualization of bland, norm ochromatic, oval nuclei as well as small arterioles transecting the ti ssue fragment, whereas the extracellular matrix became invisible. The metachromatic, extracellular matrix in the smears correlated with the reticular fibrillar network wrapping around individual tumor cells on tissue sections, one of the histopathologic criteria that separates lo w grade from high grade ESS.