Clinical Features and Outcome of the Tall Cell Variant of Papillary Thyroid Carcinoma

Objectives: To study the clinical features and outcome of the tall cell variant (TCV) of papillary thyroid carcinoma (PTC). Study Design and Methods: A single-institution retrospective analysis was performed to review patients with TCV and the usual type of PTC diagnosed from 1960 to 2000. Results: 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). Conclusion: 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.