title: Proliferating trichilemmal tumors: a review of the literature.
abstract: BACKGROUND
  Proliferating trichilemmal tumors (PTTs) are uncommon lesions whose histologic hallmark is the presence of trichilemmal keratinization. PTT is thought to originate from the trichilemmal cyst (TC) and have the potential for malignant transformation, at which point it is termed a malignant proliferating trichilemmal tumor (MPTT). These lesions may cause considerable morbidity and even mortality, and recurrence after simple local excision is common.
  
  
  OBJECTIVE
  The objective was to review the clinical presentation, histopathologic characteristics, malignant potential, and treatment options for PTT.
  
  
  METHODS
  The English literature was reviewed regarding PTT, TC, and MPTT.
  
  
  RESULTS
  PTT generally presents as a subepidermal tumor on the scalp in women over the age of 60. Histologic findings may be used to differentiate PTT from TC and MPTT. Complete surgical excision is recommended; additional radiotherapy and/or chemotherapy may be used for lesions with increased invasive potential.
  
  
  CONCLUSIONS
  Adequate treatment of PTT requires skilled histopathologic examination for proper diagnosis; histologic appearance may not correlate with clinical behavior. After surgical excision, long-term clinical follow-up for evidence of metastatic disease is judicious.
authors.affiliation: School of Medicine, Medical College of Georgia, Augusta, Georgia, USA.
authors.forename: Anita K
authors.initials: AK
authors.lastname: Satyaprakash
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Sheehan
authors.forename: Omar P
authors.initials: OP
authors.lastname: Sangüeza
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000473:pathology*; D004814:Epidermal Cyst / Q000000981:diagnostic imaging / Q000473:pathology*; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D011859:Radiography; D012189:Retrospective Studies; D012535:Scalp; D012878:Skin Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*