title: [Two cases of lower abdominal tumors difficult to differentiate from urachal tumors].
abstract: METHODS
  A 28-year-old woman visited a local medical doctor, complaining of abdominal pain, urinary frequency and a sense of residual urine. Magnetic resonance imaging revealed a lower abdominal extraperitoneal tumor, approximately 5 cm in diameter, adjacent to the bladder dome. It was thought to be a urachal tumor, and she was referred to our hospital. A hard hen's egg-sized mass was palpable in the lower abdomen. Urinary analysis was normal. Cytological examination was also negative. Cystoscopy revealed redness in the bladder dome mucosa. Although the preoperative diagnosis was a urachal cancer, the pathological diagnosis on surgery was desmoids, and tumor excision was performed. No recurrence has been seen for 7 years postoperatively.
  
  
  METHODS
  A 71-year-old man complaining of swelling of the lower abdomen was referred to our department because he was suspected to have a urachal tumor, of about 15 cm in diameter, on computed tomography. A hard infant head-sized mass was palpable in the lower abdomen. Urinary analysis was normal. Cystoscopical examination showed a markedly compressed bladder dome, however, no abnormal findings were seen in the mucosa. Although the preoperative diagnosis was a urachal tumor, the intraoperative pathological diagnosis revealed no malignancy. The mass was connected to the bladder dome, and partial cystectomy was conducted. The final pathological diagnosis was a solitary fibrous tumor. No recurrence has been seen for 5 years postoperatively. Because a urachal tumor is highly malignant, radical cystectomy and urinary diversion might be planned preoperatively. However, care should be taken not to be too invasive, considering the possibility of a benign tumor.
authors.affiliation: Department of Urology, Shinshu Ueda Medical Center. h.mizusawa@nagano-hosp.go.jp
authors.forename: Hiroya
authors.initials: H
authors.lastname: Mizusawa
authors.affiliation: Department of Urology, Shinshu Ueda Medical Center.
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Oguchi
authors.affiliation: Department of Urology, Shinshu Ueda Medical Center.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Domen
authors.affiliation: Department of Urology, Shinshu Ueda Medical Center.
authors.forename: Koji
authors.initials: K
authors.lastname: Koizumi
authors.affiliation: Department of Urology, Shinshu Ueda Medical Center.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Mimura
authors.affiliation: Department of Urology, Shinshu Ueda Medical Center.
authors.forename: Tetsuichi
authors.initials: T
authors.lastname: Saito
authors.affiliation: Department of Urology, Shinshu University, School of Medicine.
authors.forename: Haruaki
authors.initials: H
authors.lastname: Kato
mesh_terms: D000008:Abdominal Neoplasms / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D018222:Desmoid Tumors / Q000175:diagnosis; D006801:Humans; D008297:Male; D054364:Solitary Fibrous Tumors / Q000175:diagnosis; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis*