title: Intra-articular angioleiomyoma of the knee with an atypical finding on gadolinium-enhanced magnetic resonance imaging: a case report.
abstract: BACKGROUND
  Angioleiomyoma is a benign smooth muscle tumor. It originates in the tunica media of veins. In general, it arises from the dermis, subcutaneous fat and fascia of lower extremities in middle-aged women. The case of intra-articular occurrence is very rare.
  
  
  METHODS
  This case report describes a 30-year-old Asian man with a 6-month history of recurrent pain localized in the lateral side of his left knee. Magnetic resonance imaging revealed an isolated intra-articular lesion. We performed a surgical excision of this lesion. On histological examination, the diagnosis of angioleiomyoma was confirmed. After the surgery, he recovered completely. Furthermore, no sign of recurrence was observed 1 year after surgery.
  
  
  CONCLUSIONS
  In this study, we report a rare case of intra-articular angioleiomyoma of the knee. The mass showed atypical findings on magnetic resonance imaging including gadolinium-enhanced imaging in comparison to previously reported intra-articular lesions. This intra-articular tumor is difficult to diagnose prior to surgery due to paucity of information.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Fukawa
authors.forename: Yorikazu
authors.initials: Y
authors.lastname: Akatsu
authors.affiliation: Department of Orthopaedic Surgery, Graduated School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan. sasho@faculty.chiba-u.jp.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Sasho
mesh_terms: D000328:Adult; D018229:Angiomyoma / Q000175:diagnosis*; D005682:Gadolinium; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male
chemical_list: D005682:Gadolinium