title: An unusual case of an intramuscular lipoma of the pectoralis major muscle simulating a malignant breast mass.
abstract: BACKGROUND
  Intramuscular lipomas of the pectoralis major muscle are rare and may mimic malignant breast tumours.
  
  
  METHODS
  A 58-year-old Chinese woman presented with a 2- year history of an enlarging left breast mass. Clinical examination revealed a palpable hard mass in the left breast.
  
  
  METHODS
  Standard mammographic views revealed a radiolucent mass deep in the left pectoralis major muscle. The mass was homogeneously hypoechoic with smooth margins on ultrasound.
  
  
  RESULTS
  Surgical excision of the mass was performed. Histological diagnosis was an intramuscular lipoma of the left pectoralis major muscle.
  
  
  CONCLUSIONS
  Recognition of the radiolucent density and submammary location of a pectoralis major muscle lipoma is important as it allows the correct diagnosis to be made.
authors.affiliation: Department of Diagnostic Radiology, Singapore General Hospital.
authors.forename: R
authors.initials: R
authors.lastname: Pant
authors.forename: A C C
authors.initials: AC
authors.lastname: Poh
authors.forename: S G
authors.initials: SG
authors.lastname: Hwang
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008067:Lipoma / Q000473:pathology*; D008875:Middle Aged; D019042:Muscle Neoplasms / Q000473:pathology*; D010369:Pectoralis Muscles