Tall Cell Variant of Papillary thyroid Carcinoma – How Many Tall Cells Are Needed?
Matthias S Dettmer, Anja Schmitt, Hans Steinert, Holger Moch, Paul Komminoth, Aurel Perren. University of Pittsburgh, Pittsburgh, PA; University of Bern, Bern, Switzerland; University Hospital Zurich, Zurich, Switzerland; Triemlispital, Zurich, Zurich, Switzerland
Background: Differentiated papillary thyroid cancers (PTC) have a favorable 5-year survival rate of >95%. However, it is difficult to identify patients with an adverse clinical outcome (ACO). The tall cell variant of PTC (TCV) is known to have an ACO, but there are different diagnostic criteria in the literature.
Design: We evaluated histomorphologic criteria in 126 patients with PTC. To enhance the portion of papillary carcinomas with an ACO, we collaborated with all nuclear medicine departments of the Canton, Zürich. 56 patients with an ACO, defined as more than one relapse or tumor related death were identified. They were compared with a control group (CG) of 70 age-stage-gender-matched PTC. All tumors were reevaluated by three pathologists. The tumor type was determined according to the 2004 WHO classification and the percentage of tall cells (TC) in the PTCs was measured semiquantitatively. TCs were defined to be more than three times as high as wide.
Results: We found 48 TCV (38%), with a cut off of 10% TC per PTC, and 78 PTCs without any TC (62%). Kaplan-Meier analysis demonstrated a significantly worse overall survival (OS), tumor specific survival (TSS) and relapse free survival (RFS) (P <0.001) in patients with tumors containing an area composed of 10% or more TCs. TC above 10% was the only constant significant factor in a multivariate analysis (COX regression) for the OS, TSS and RFS, including age, stage and gender.
Conclusions: A 10% TC-quantity within a papillary carcinoma is strongly associated with an ACO and should therefore be reported. Following studies must show whether patients with such tumors benefit from additional therapy.
Tuesday, March 20, 2012 1:00 PM
Poster Session IV # 29, Tuesday Afternoon