Diffuse Histiocytic Proliferation Mimicking Mesothelial Hyperplasia in Endocervicosis of the Female Pelvic Peritoneum

Abstract

Two cases of a diffuse histiocytic proliferation that mimicked mesothelial hyperplasia in the pelvic peritoneum of premenopausal women with endocervicosis are presented. The lesions were found incidentally on laparoscopic examination for pelvic pain and appeared as small friable excrescenses attached to the serosal surface of the pelvis. Histologic examination revealed a dense proliferation of round to oval cells with abun dant eosinophilic cytoplasm and large, hyperchromatic nuclei showing focal invagina tions and occasional mitoses. The cells appeared to infiltrate the surrounding connec tive tissue in single files and were closely associated with sloughed strands of small, cuboidal mesothelial cells as well as with larger glands lined by mucinous epithelium. Immunohistochemical studies showed cytoplasmic staining of these cells with MAC387, HAM56, and alpha-1-antichymotrypsin antibodies, thus supporting their histiocytic nature. The close association of the histiocytic proliferation with the endo cervicotic glands raises the possibility that the process may have resulted as a reaction to rupture and extrusion of the mucous contents of the glands into the surrounding stroma. These lesions must be distinguished from reactive or neoplastic mesothelial proliferations involving the female pelvic peritoneum. Int J Surg Pathol 1(2):101-106, 1993