title: Papillary clusters as a diagnostic pitfall in urinary cytology of pseudosarcomatous fibromyxoid tumor of the bladder. A case report.
abstract: BACKGROUND
  Pseudosarcomatous fibromyxoid tumor (PFT) of the urinary bladder is an uncommon benign lesion that can involve any site in the bladder. Cellular features of PFT of the bladder are exceedingly rare. We describe the urinary cytology in a PFT patient who displayed numerous papillary fragments that suggested a malignant tumor.
  
  
  METHODS
  A 52-year-old man was seen at the hospital for evaluation of gross hematuria. At cystoscopy, the urologist observed a 3-cm, smooth, polypoid and ulcerated mass extending from the trigone to the bladder neck. Urinary cytology showed many papillary clusters with irregular nuclear margins in the bloody cell background. No spindle cells were noted. Cytology was interpreted as papillary growth, factor transitional cell carcinoma, grade 2-3. A laparotomy with partial resection of the urinary bladder was carried out, and histologically the tumor was composed of spindle, stellate, fibroblastic cells embedded in myxoid stroma with little collagen. Immunohistochemical and ultrastructural studies revealed the fibroblastic nature of the lesion. The final diagnosis was PFT of the bladder on the basis of histologic examination of the resected material.
  
  
  CONCLUSIONS
  Papillary fragments are a diagnostic pitfall in urinary cytology of PFT lesions.
authors.affiliation: Department of Pathology, Laboratory Medicine, Saiseikai Shiga Hospital, Imperial Gift Foundation Inc., 2-4-1, Oh-Hashi, Ritto, Shiga 520-3046, Japan. kobayashi@v7.com
authors.forename: Tadao K
authors.initials: TK
authors.lastname: Kobayashi
authors.forename: Masami
authors.initials: M
authors.lastname: Ueda
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nishino
authors.forename: Mitsue
authors.initials: M
authors.lastname: Muramatsu
authors.forename: Suzuko
authors.initials: S
authors.lastname: Moritani
authors.forename: Hideo
authors.initials: H
authors.lastname: Seki
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Araki
authors.forename: Chiyuki
authors.initials: C
authors.lastname: Kaneko
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D002295:Carcinoma, Transitional Cell / Q000473:pathology / Q000652:urine; D003937:Diagnosis, Differential; D003951:Diagnostic Errors / Q000517:prevention & control*; D004721:Endoplasmic Reticulum / Q000473:pathology / Q000648:ultrastructure; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D005350:Fibroma / Q000473:pathology* / Q000652:urine; D006417:Hematuria / Q000209:etiology / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D001743:Urinary Bladder / Q000473:pathology* / Q000648:ultrastructure; D001749:Urinary Bladder Neoplasms / Q000473:pathology* / Q000652:urine; D014556:Urine / Q000166:cytology; D014746:Vimentin / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D014746:Vimentin; D007633:Keratins