title: Ovarian clear cell carcinoma with plasma cell-rich inflammatory stroma: a clear cell carcinoma subgroup with distinct clinicopathological features.
abstract: OBJECTIVE
  Ovarian clear cell carcinoma has a unique stroma. Although a hyalinized or mucoid stroma is more common, the stroma sometimes shows a dense inflammatory infiltrate, simulating a dysgerminoma. The aim of this study was to analyse the character and significance of the inflammatory stroma.
  
  
  RESULTS
  Twelve of 60 (20%) clear cell carcinomas showed an inflammatory stroma. The inflammatory stroma and hyalinized/mucoid stroma were mutually exclusive. Inflammatory cells were predominantly composed of CD138-positive plasma cells. As compared with the non-inflammatory cases, the epithelial component frequently showed a solid growth pattern and immunoreactivity for cyclooxygenase-2, one of the critical proinflammatory enzymes (P < 0.005). These findings were repeated after heterotransplantation of three clear cell carcinoma cell lines into athymic nude mice. In particular, xenografts of one cell line (JHOC-5) were infiltrated by mature plasma cells, indicating that plasma cell differentiation was stimulated by JHOC-5 cells, independently of T lymphocytes. Clinicopathologically, the frequency of International Federation of Gynaecology and Obstetrics stage III was higher in the cases with an inflammatory stroma than in those without it (P < 0.01).
  
  
  CONCLUSIONS
  Clear cell carcinomas with an inflammatory stroma constitute a distinct clinicopathological subgroup. It is strongly suggested that tumour cells themselves are responsible for inducing inflammation and stimulating plasma cell differentiation in a paracrine manner.
authors.affiliation: Department of Anatomical Pathology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Kato
authors.affiliation: Department of Pathology, Aomori Prefectural Central Hospital, Aomori, Japan.
authors.forename: Hidekachi
authors.initials: H
authors.lastname: Kurotaki
authors.affiliation: Department of Pathology, Tsuruoka Municipal Shonai Hospital, Tsuruoka, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Uchigasaki
authors.affiliation: Department of Pathology, Tsuruoka Municipal Shonai Hospital, Tsuruoka, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Fukase
authors.affiliation: Department of Anatomical Pathology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kurose
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000473:pathology*; D000818:Animals; D005260:Female; D064593:Heterografts; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000473:pathology*; D051379:Mice; D008819:Mice, Nude; D010051:Ovarian Neoplasms / Q000473:pathology*; D010950:Plasma Cells / Q000473:pathology*
keywords: clear cell carcinoma; cyclooxygenase-2; inflammatory stroma; ovary; plasma cell