title: Two distinctive subungual pathologies: subungual exostosis and subungual osteochondroma.
abstract: BACKGROUND
  The purpose of this study was to present features that differentiate subungual exostosis from subungual osteochondroma.
  
  
  METHODS
  We treated 11 patients for subungual masses. All were confirmed by radiographic and histologic evaluations to be subungual exostosis or subungual osteochondroma. The study patients comprised eight female and three male patients with a mean age at presentation of 18.7 years (range 1.5 to 70.9). In the five patients with subungual exostosis, three (60%) had a toe lesion, and two (40%) had a finger lesion. In the six patients with subungual osteochondroma, four (67%) had a toe lesion, and two (33%) had finger lesions. We analyzed the clinical features, including trauma history, the existence of infection before surgery, tumor recurrence, and postoperative nail deformity.
  
  
  RESULTS
  In all patients, the lesions presented as an exophytic tumor of the nail apparatus, beneath the nail plate, which varied in size from 0.6 x 0.4 cm to 1.2 x 0.9 cm. Excision of these masses produced useful toes or fingers without pain, a tender scar, or nail deformity. Although nails were deformed preoperatively, they grew back without ridges or cracks within 3 to 5 months postoperatively. There were no recurrences based on clinical and radiographic evaluations, and both tumor types showed characteristic radiographic and histologic differences.
  
  
  CONCLUSIONS
  Subungual exostosis and subungual osteochondroma are benign but have distinct osseous pathologies. We concluded that subungual exostosis is clinically, developmentally, radiographically, and histologically distinct from subungual osteochondroma.
authors.affiliation: Department of Orthopaedics, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Sang Ki
authors.initials: SK
authors.lastname: Lee
authors.forename: Moon Sang
authors.initials: MS
authors.lastname: Jung
authors.forename: Young Ho
authors.initials: YH
authors.lastname: Lee
authors.forename: Hyun Sik
authors.initials: HS
authors.lastname: Gong
authors.forename: Jae Kwang
authors.initials: JK
authors.lastname: Kim
authors.forename: Goo Hyun
authors.initials: GH
authors.lastname: Baek
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000473:pathology* / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005096:Exostoses / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009260:Nail Diseases / Q000473:pathology* / Q000601:surgery; D009262:Nails / Q000473:pathology; D015831:Osteochondroma / Q000473:pathology* / Q000601:surgery