title: Sonographic findings of ruptured epidermal inclusion cysts in superficial soft tissue: emphasis on shapes, pericystic changes, and pericystic vascularity.
abstract: OBJECTIVE
  The purpose of this study was to retrospectively evaluate the sonographic findings of ruptured epidermal inclusion cysts in superficial soft tissue, with an emphasis on shapes, pericystic changes, and pericystic vascularity.
  
  
  METHODS
  The cases of 61 patients with surgically confirmed epidermal inclusion cysts were reviewed, and 13 patients were found to have ruptured cysts. The Ethics Committees of our institutions did not require patient approval or informed patient consent for this retrospective study. We evaluated the shapes, sizes, locations, pericystic changes, and pericystic vascularity for the 13 cases.
  
  
  RESULTS
  The shapes of the ruptured epidermal inclusion cysts were classified into 3 types: with lobulations (type I, 2 cases), with protrusions (type II, 8 cases), and with abscess pocket formations (type III, 3 cases). The mean long diameter of the cysts was 3 cm. Common sites of ruptured epidermal inclusion cysts were the plantar surface of the metatarsophalangeal joint (4 cases) and buttocks (3 cases). Pericystic changes were noted in all of the type II and III cysts. Increased vascularity on color Doppler sonography was prominent in 3 type II cysts and 3 type III cysts. Deep abscess formation was noted in the epidermal inclusion cysts, especially for the type III cysts.
  
  
  CONCLUSIONS
  A ruptured epidermal inclusion cyst visualized by sonography had variable shapes; the sonographic findings can be useful for obtaining a correct diagnosis of a ruptured epidermal inclusion cyst.
authors.affiliation: Department of Radiology, East-West Neo Medical Center, Seoul Korea. jinooki@hitel.net
authors.forename: Wook
authors.initials: W
authors.lastname: Jin
authors.forename: Kyung Nam
authors.initials: KN
authors.lastname: Ryu
authors.forename: Gou Young
authors.initials: GY
authors.lastname: Kim
authors.forename: Hyun Cheol
authors.initials: HC
authors.lastname: Kim
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Lee
authors.forename: Ji Seon
authors.initials: JS
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003937:Diagnosis, Differential; D004814:Epidermal Cyst / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012422:Rupture, Spontaneous; D014463:Ultrasonography