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proliferating trichilemmal cyst

Thursday 2 June 2016



- Proliferating trichilemmal cyst : bland squamous proliferation and abrupt trichilemmal keratinization


  • Proliferating trichilemmal cysts grow rapidly and may also arise de novo.
  • Although biologically benign, they may be locally aggressive, becoming large and ulcerated.
  • Rarely, malignant transformation leads to distant metastases.
  • No absolute clinical criteria can distinguish malignant from benign proliferating pilar tumors.
  • The entire lesion must undergo histological evaluation to assess for malignancy.
  • Atypia and a high mitotic rate are suggestive of malignancy.

See also

- cutaneous cysts ( cutaneous cystic anomalies )

  • trichilemmal cyst