title: Anaplastic transformation of papillary thyroid carcinoma in recurrent disease in regional lymph nodes: a histologic and immunohistochemical study.
abstract: OBJECTIVE
  Although the prognosis of papillary thyroid carcinoma is favorable in most cases, recurrent disease in the regional lymph nodes is not uncommon, and some patients die of recurrent disease that ultimately becomes unresectable. We studied the proliferative activity of cancer cells in recurrent foci in lymph nodes to see whether repeated recurrences might result in anaplastic transformation of papillary thyroid carcinoma.
  
  
  METHODS
  Fourteen patients with papillary thyroid carcinoma who underwent reoperation for recurrent disease in the regional lymph nodes more than once were the subjects of the study. The histologic findings and proliferative activity of carcinoma foci at each recurrence were studied histologically and immunohistochemically.
  
  
  RESULTS
  There were higher incidences of histologic features of poorly differentiated thyroid carcinoma in the metastatic foci in the lymph nodes as it recurred repeatedly, and the labeling indexes of proliferating cell nuclear antigen (PCNA) and nuclear antigen Ki-67 (MIB-1) increased.
  
  
  CONCLUSIONS
  These observations suggest that papillary thyroid carcinoma may become more malignant, even undergo transformation to an anaplastic variety, as metastatic disease in the regional lymph nodes recurs repeatedly.
authors.affiliation: Surgery Branch, Ito Hospital, Tokyo, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Ozaki
authors.forename: K
authors.initials: K
authors.lastname: Ito
authors.forename: T
authors.initials: T
authors.lastname: Mimura
authors.forename: K
authors.initials: K
authors.lastname: Sugino
authors.forename: K
authors.initials: K
authors.lastname: Ito
mesh_terms: D002291:Carcinoma, Papillary / Q000378:metabolism / Q000556:secondary*; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000473:pathology*