title: The reliability of a second biopsy for determining residual tumor.
abstract: BACKGROUND
  Often after biopsy a skin cancer appears to resolve clinically and a repeat biopsy may be done on the area in question before proceeding with further treatment.
  
  
  OBJECTIVE
  Our purpose was to assess the value of a subsequent biopsy in the treatment of skin cancers previously diagnosed by biopsy results.
  
  
  METHODS
  The results of a subsequent biopsy were compared with the results of Mohs micrographic surgery in 291 patients with biopsy-established basal cell carcinoma and squamous cell carcinoma. Pre-Mohs surgery curettings were examined in 60 of these patients to evaluate whether these could have caused false-negative Mohs results.
  
  
  RESULTS
  One hundred nineteen patients had a negative second biopsy, of which 75 (63%) had residual tumor at surgery. Eight of 60 patients in whom the curettings were examined had negative results from both biopsy and Mohs surgery; tumor in the curettings was shown in six of these eight patients (75%).
  
  
  CONCLUSIONS
  This study suggests that 63% or more of subsequent biopsy specimens for skin cancer may yield false-negative results and casts doubt on the usefulness of a subsequent biopsy before surgery.
authors.affiliation: Loma Linda University, CA.
authors.forename: A
authors.initials: A
authors.lastname: Torres
authors.forename: J
authors.initials: J
authors.lastname: Seeburger
authors.forename: D
authors.initials: D
authors.lastname: Robison
authors.forename: R
authors.initials: R
authors.lastname: Glogau
mesh_terms: D001706:Biopsy; D002280:Basal Cell Carcinoma / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D003475:Curettage; D005153:Facial Neoplasms / Q000473:pathology*; D006801:Humans; D015580:Mohs Surgery; D015203:Reproducibility of Results; D012867:Skin / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*