The tall-cell variant of papillary thyroid carcinoma: a multivariate analysis of clinical risk factors.

Abstract

The biological behaviour of the tall-cell variant (TCV) of papillary thyroid carcinoma (PTC) remains to be clarified in a multivariate analysis that controls for all relevant clinicopathological parameters. A retrospective analysis was carried out of 332 consecutive PTC patients operated on at a university hospital between November 1994 and February 2003. A total of 16 TCV tumours (4.8%) was identified among the 332 PTC patients. Nodal and (predominantly pulmonary) distant metastases were identified at surgery in, respectively, 50% and 31% of TCV tumours. On univariate analysis, only the association between the TCV and distant metastasis retained statistical significance after adjustment for multiple testing. On multivariate logistic regression analysis, the presence of distant metastasis increased more than fourfold [odds ratio (OR) 4.2] the chance of having the TCV of PTC, with controls for extrathyroidal extension, nodal metastasis, operation status, patient gender, categorized patient age, and categorized primary tumour diameter. The increased risk of distant metastasis associated with the TCV morphology of PTC warrants an extensive post-operative search for distant metastasis to facilitate early diagnosis and treatment of tumour deposits in distant organs.