title: Chronic expanding hematoma, ruptured through the skin 53 years after buttock contusion.
abstract: BACKGROUND
  Chronic expanding hematoma is a relatively rare complication of soft tissue trauma and often clinically mistaken for a malignant neoplasm.
  
  
  METHODS
  A 71-year-old female presented with a chronic expanding hematoma that ruptured through the buttock skin 53 years after the original contusion. The diagnosis of CEH was made based on the results of the biopsy, physical examination, and CT. The tumor was completely excised, and the defect was covered with a rhomboid flap.
  
  
  CONCLUSIONS
  There are no reports of lesions rupturing through the skin. Almost all instances of chronic expanding hematoma previously reported in the English literature have a history ranging from 1 month to 20 years. There is a report of a thorax CEH that ruptured into the lung parenchyma after 24 years, so it is conceivable that other subcutaneous CEHs could break through the skin several decades after their inception.
  
  
  CONCLUSIONS
  Once this lesion has ruptured, its differentiation from other entities becomes more complicated.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Showa University, Tokyo, Japan. Electronic address: dmorioka@gmail.com.
authors.forename: Daichi
authors.initials: D
authors.lastname: Morioka
authors.affiliation: Department of Plastic and Reconstructive Surgery, Showa University, Tokyo, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Ohkubo
authors.affiliation: Department of Plastic and Reconstructive Surgery, Showa University, Tokyo, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Umezawa
keywords: Buttock; Chronic expanding hematoma; Differential diagnosis; Soft tissue tumor