title: Well-differentiated papillary mesothelioma in the pelvic cavity. A case report.
abstract: BACKGROUND
  Well-differentiated papillary mesothelioma (WDPM) is considered to be a distinct subtype of peritoneal mesothelioma. It occurs in the peritoneum, is most commonly seen in young women and is found incidentally at laparotomy for other indications. Clinically, WDPM is considered to be benign or to have low malignancy potential.
  
  
  METHODS
  A 48-year-old female with no history of asbestos exposure presented with hypermenorrhea. An operation was performed for adenomyosis, and six papillary nodules, 2 cm or less, were found in the serosa of the pelvic cavity. Peritoneal lavage fluid and imprint material from the tumor were obtained for cytologic examination. The cytologic specimens showed many scattered cells and sheetlike clusters and some papillary clusters. These cells had abundant, polygonal, cyanophilic cytoplasm; clearly outlined borders; and slitlike intercellular spaces. The cell arrangement was orderly. The nuclei were uniform in size, with a single centrally located nucleolus, and there were no binucleated forms or mitosis. There was no increase in chromatin. On the luminal surface of the cells, a brush border was observed.
  
  
  CONCLUSIONS
  It is important to differentiate WDPM from diffuse malignant mesothelioma or other peritoneal malignant tumors to avoid treating them as malignant tumors.
authors.affiliation: Department of Pathology, Osaka City University Hospital, 1-5-7, Asahi-machi, Abeno-ku, Osaka City, Osaka, 545-8586, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Haba
authors.forename: Kenichi
authors.initials: K
authors.lastname: Wakasa
authors.forename: Masaomi
authors.initials: M
authors.lastname: Sasaki
mesh_terms: D064032:Calbindin 2; D003581:Cytodiagnosis; D004715:Endometriosis / Q000601:surgery; D005260:Female; D006801:Humans; D007633:Keratins / Q000378:metabolism; D008654:Mesothelioma / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D010048:Ovarian Cysts / Q000473:pathology; D010051:Ovarian Neoplasms / Q000473:pathology; D010386:Pelvic Neoplasms / Q000175:diagnosis / Q000473:pathology*; D010534:Peritoneal Neoplasms / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D018180:Thrombomodulin / Q000378:metabolism
chemical_list: D064032:Calbindin 2; D064030:S100 Calcium Binding Protein G; D018180:Thrombomodulin; D007633:Keratins