title: Cytokeratin-positive interstitial reticulum cell tumor: recognition of a potential "in situ" pattern.
abstract: Cytokeratin-positive interstitial reticulum cell (CIRC) tumor is a very rare accessory cell neoplasm of lymphoid organs derived from fibroblastic reticulum cells, which originate from mesenchymal stem cells. We describe the histologic, immunophenotypical, and molecular features of a CIRC tumor in a 67-year-old woman who underwent hysterectomy, bilateral adnexectomy, and pelvic lymphadenectomy for endometrial carcinoma. An enlarged pelvic node contained circumscribed neoplastic infiltrates in perifollicular and interfollicular areas consisting of large cells arranged in a reticular pattern with nuclear atypia, atypical mitoses, and apoptosis, but without glandular architecture or disruption of overall architecture. The atypical infiltrate coexpressed cytokeratin and vimentin, partially CD68, CD163, and lysozyme, but lacked markers of endometrial carcinoma, consistent with a diagnosis of CIRC tumor. Despite the obviously neoplastic cytological features, immunostains revealed the circumscribed and noninvasive pattern of the lesion, possibly representing an early "in situ" stage of CIRC tumor.
authors.affiliation: Department of Pathology, University Hospital of Tübingen, D-72076 Tübingen, Germany. Electronic address: hans.boesmueller@med.uni-tuebingen.de.
authors.forename: Hans
authors.initials: H
authors.lastname: Bösmüller
authors.affiliation: Department of Gynecology and Obstetrics, Zollernalb-Klinikum, D-72458 Albstadt, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Klenske
authors.affiliation: Department of Pathology, University Hospital of Tübingen, D-72076 Tübingen, Germany.
authors.forename: Irina
authors.initials: I
authors.lastname: Bonzheim
authors.affiliation: Department of Pathology, University Hospital of Tübingen, D-72076 Tübingen, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Scharpf
authors.affiliation: Department of Pathology, University Hospital of Tübingen, D-72076 Tübingen, Germany.
authors.forename: Naomi
authors.initials: N
authors.lastname: Rieger
authors.affiliation: Department of Pathology, University Hospital of Tübingen, D-72076 Tübingen, Germany.
authors.forename: Letitia
authors.initials: L
authors.lastname: Quintanilla-Fend
authors.affiliation: Department of Pathology, University Hospital of Tübingen, D-72076 Tübingen, Germany.
authors.forename: Falko
authors.initials: F
authors.lastname: Fend
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D001706:Biopsy; D049109:Cell Proliferation; D003937:Diagnosis, Differential; D005260:Female; D005347:Fibroblasts / Q000737:chemistry* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis*; D008198:Lymph Nodes / Q000737:chemistry* / Q000473:pathology; D008232:Lymphoproliferative Disorders / Q000378:metabolism* / Q000473:pathology; D011237:Predictive Value of Tests
chemical_list: D014408:Biomarkers, Tumor; D007633:Keratins
keywords: CIRC; Cytokeratin-positive interstitial reticulum cells; Fibroblastic reticulum cells; In situ pattern; Pitfall in a frozen section