Clinical features and outcome of the tall cell variant of papillary thyroid carcinoma.

Abstract

To study the clinical features and outcome of the tall cell variant (TCV) of papillary thyroid carcinoma (PTC). A single-institution retrospective analysis was performed to review patients with TCV and the usual type of PTC diagnosed from 1960 to 2000. Fourteen of 1,108 patients (median follow-up, 8.9 yr) diagnosed with PTC had TCV. Ten were female, and four were male, with a mean age of 53.7 (33-81) years. All were ethnic Chinese. Compared with the usual PTC cohort, TCV patients presented at an older age (mean, 53.7 vs. 45.2 yr; P = .015). They had a higher rate of extrathyroidal extension (78.6% vs. 43.4%, P = .009), tracheal invasion (28.6% vs. 9%, P = .034), and carotid vessel invasion (14.3% vs. 1.5%, P = .021). TCV patients had more frequent gross (42.9% vs. 17.2%) and microscopic (14.3% vs. 6%) postoperative locoregional residual disease (P = .008). They also had a higher percentage of stage III and IV disease (American Joint Committee on Cancer, 6th ed) (74.3% vs. 31.3%, P = .009). Ten-year local failure-free, regional failure-free, and metastasis-free survival were worse in the TCV group (78.6% vs. 88.8%. P = .017; 53.0% vs. 85.9%, P < .0001; 35.7% vs. 92.1%, P < .0001, respectively). The 10-year cause-specific survival was also lower in TCV patients (48.2% vs. 93.4%, P < .0001). TCV presents at a higher stage with more advanced local disease. It has a higher risk of locoregional and distant relapse and a worse overall survival rate. Stratification by stage reveals that TCV has significantly higher mortality compared with PTC for stage IV disease. Aggressive treatment and close follow-up of these patients is necessary.