title: Duplicitous growth of infiltrative basal cell carcinoma: Analysis of clinically undetected tumor extent in a paired case-control study.
abstract: BACKGROUND
  Many clinicians believe infiltrative basal cell carcinoma (BCC) is a more difficult tumor to eradicate than nodular BCC because the growth of infiltrative BCC is not easy to detect clinically. However, data supporting this observation are largely anecdotal.
  
  
  OBJECTIVE
  Our purpose was to show that infiltrative BCC have wider and deeper tumor extensions than nodular BCC of similar clinical size.
  
  
  METHODS
  In this retrospective study, 139 cases of infiltrative BCC excised by Mohs micrographic surgery (MMS) were matched to a control group of 139 cases of nodular BCC similarly excised. They were paired by site, size, number of recurrences, age, gender, and previous treatment type. The cases were selected and paired by computer from 1197 consecutive BCC (primary and recurrent) referred for MMS over a 5-year period. MMS technique allowed us to quantitate the extent of tumor spread using three measurements: the number of surgical stages required for complete removal of tumor, the width of tissue required to remove subclinical extension of tumor, and the depth of defect at completion of MMS.
  
  
  RESULTS
  Analysis showed the infiltrative BCC was more difficult to detect and to eradicate than the nodular BCC. The number of surgical stages required for complete removal of tumor, the width of tissue required to remove subclinical extension of tumor, and the depth of defect at completion of MMS were all greater with infiltrative BCC when compared with nodular BCC regardless of whether cases were primary or recurrent. These differences were all statistically significant.
  
  
  CONCLUSIONS
  Infiltrative BCC can be significantly more destructive than nodular BCC because tumor extension is difficult to detect clinically. Clinicians should treat infiltrative BCC with its potential for convert invasion in mind.
authors.affiliation: Department of Dermatology, University of Virginia School of Medicine, Charlottesville, 22908, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Hendrix
authors.forename: H L
authors.initials: HL
authors.lastname: Parlette
mesh_terms: D000328:Adult; D000368:Aged; D002280:Basal Cell Carcinoma / Q000473:pathology* / Q000601:surgery; D016022:Case-Control Studies; D002455:Cell Division / Q000502:physiology*; D062109:Dermatologic Surgical Procedures; D005153:Facial Neoplasms / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015580:Mohs Surgery; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000601:surgery; D009367:Neoplasm Staging; D012086:Reoperation; D012189:Retrospective Studies; D012867:Skin / Q000473:pathology; D012878:Skin Neoplasms / Q000473:pathology* / Q000601:surgery; D012984:Software; D016896:Treatment Outcome; D014945:Wound Healing / Q000502:physiology