The adjunctive value of CD10 immunostaining on cell block preparations in pelvic endometriosis

OBJECTIVE: To evaluate the utility of CD10 immunostaining on cell block preparations from pelvic washing cytology material obtained during laparoscopy in cases of pelvic endometriosis (PE). STUDY DESIGN: Six premenopausal women presenting with ovarian masses underwent a laparoscopic procedure. In addition to routine cytospin preparations, cell blocks were prepared using the formalin-fixed, paraffin-embedded method from the pelvic washings in each case. Immunocytochemistry using monoclonal antibodies for cytokeratin (CK) 7, CK20, CD10, estrogen receptor (ER), progesterone receptor (PR) and CA125 was performed on sections from cell blocks using the streptavidin-biotin peroxidase complex. RESULTS: Clusters of epithelial cells (3 cases) and stromal cells (2 cases) were seen in a background rich in hemosiderin-laden macrophages and poorly preserved mesothelial cells on cytospin smears. CD10 and CK7 were consistently positive in the stromal and epithelial components, respectively, in all cases on cell block sections. Variable staining reactions were noted for ER, PR and CA125. CONCLUSION: CD10 immunostaining is a useful ancillary method in the diagnosis of endometriosis. Its routine use on cell block preparations from pelvic washings in women undergoing a laparoscopic procedure is recommended.