title: New classification of midline cysts of the prostate in adults via a transrectal ultrasonography-guided opacification and dye-injection study.
abstract: OBJECTIVE
  To reclassify midline cysts (MLCs) of the prostate according using the results from transrectal ultrasonography (TRUS)-guided opacification and dye injection.
  
  
  METHODS
  Eighty-six patients (mean age 60.9 years) who had MLCs detected in the pelvis by TRUS were investigated. In all patients the size of the MLC was measured and they had transperineal aspiration under TRUS guidance. After aspiration of the MLC a mixture of water-soluble contrast medium and indigo carmine dye was injected to check for communication with the urethra or seminal tract by endoscopic and pelvic X-ray examination.
  
  
  RESULTS
  We classified MLCs into four categories: (i) type 1 (nine cases), MLC with no communication into the urethra (traditional prostatic utricle cyst); (ii) type 2a (60 cases), MLC with communication into the urethra (cystic dilatation of the prostatic utricle, CDU); (iii) type 2b (14 cases), CDU which communicated with the seminal tract; (iv) type 3 (three cases), cystic dilation of the ejaculatory duct. The location, shape and volume of the MLC, and the prostate-specific antigen level of MLC fluid, did not influence the classification.
  
  
  CONCLUSIONS
  The most common type of MLC was CDU. A new classification that depends on the communication with the urethra or seminal tract is proposed.
authors.affiliation: Shinshu University School of Medicine, Matsumoto, Japan. r.furuya@furuya-hospital.jp
authors.forename: Ryoji
authors.initials: R
authors.lastname: Furuya
authors.forename: Seiji
authors.initials: S
authors.lastname: Furuya
authors.forename: Haruaki
authors.initials: H
authors.lastname: Kato
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Saitoh
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takahash
authors.forename: Taiji
authors.initials: T
authors.lastname: Tsukamoto
mesh_terms: D000328:Adult; D002329:Carmine; D003287:Contrast Media; D003560:Cysts / Q000145:classification* / Q000000981:diagnostic imaging; D004543:Ejaculatory Ducts / Q000000981:diagnostic imaging; D019160:Endosonography / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D009095:Mullerian Ducts / Q000000981:diagnostic imaging; D011467:Prostate / Q000000981:diagnostic imaging*; D011469:Prostatic Diseases / Q000145:classification* / Q000000981:diagnostic imaging; D012669:Seminal Vesicles / Q000000981:diagnostic imaging
chemical_list: D003287:Contrast Media; D002329:Carmine