Background: The recent WHO classification (2017) reports that the definition of TCV-PTC requires >30% of tall cells (TC), differently from the previous definition of >50% (2004 WHO classification). However, a Japanese study showed that PTC with >50% TC had a worse outcome than PTC with 30–49% TC. Recently, an Italian consensus recommends 10% TC as cut-off for TCV-PTC definition. Therefore, the diagnostic criteria for TCV-PTC definition need further verifications. Aim: 1) To evaluate the difference of presentation and outcome among CV-PTC, TCV-PTC (with >50% TC) and CV/TC-PTC (with <50% TC); 2) To identify the % of TC that impacts on the prognosis. Methods: We evaluated 610 patients with PTC, divided in: group-A (CV-PTC; 417/610–68.4%), group-B (CV/TC-PTC; 64/610–10.5%) and group-C (TCV-PTC; 129/610–21.1%). Results: No difference were found in the majority of epidemiological and clinical features with the exception of an older age in group-C (p = 0.02). At variance, neoplastic emboli were more frequent in group-B (23.4%) vs C (13.2%) and A (9.8%). Similarly microscopic extra-thyroidal-extension (ETE) was more present in group-C (73.6%) vs B (57.8%) and A (39.6%) (p<0.01). Stage-I was less frequent in group-C (82.2%) vs B (96.9%) and A (94.7%) (p<0.01). Lower activities of 131I were used in group-A (87.1%), vs B (79.7%) and C (74.4%) (p<0.01). After 6 years, we found more structural persistent disease (StR) in group- B (13.1%) vs C (8.9%) and A (4.9%) (p<0.01). Regarding the impact of %TC on the prognosis, only CV/TC-PTC with <10% TC had no StR at the end of follow-up while no major differences in StR was found among cases with a 20-40% of TC (all together 14.5% of StR). Conclusions: the presence of TC, also if <50% but >10% identifies a subgroup of PTC with a biological behavior more similar to TCV-PTC than CV-PTC. Our findings are in line with the indications of the Italian consensus that 10% of TC is enough to define the TCV-PTC.

The presence of a tall cells>10% in a classical variant of papillary thyroid carcinoma (CV-PTC) makes its aggressiveness similar to that of tall cell variant (TCV-PTC)

Antonio Matrone;Carla Gambale;Liborio Torregrossa;Laura Valerio;Laura Agate;David Viola;Eleonora Molinaro;Fulvio Basolo;Paolo Vitti;Rossella Elisei
2019-01-01

Abstract

Background: The recent WHO classification (2017) reports that the definition of TCV-PTC requires >30% of tall cells (TC), differently from the previous definition of >50% (2004 WHO classification). However, a Japanese study showed that PTC with >50% TC had a worse outcome than PTC with 30–49% TC. Recently, an Italian consensus recommends 10% TC as cut-off for TCV-PTC definition. Therefore, the diagnostic criteria for TCV-PTC definition need further verifications. Aim: 1) To evaluate the difference of presentation and outcome among CV-PTC, TCV-PTC (with >50% TC) and CV/TC-PTC (with <50% TC); 2) To identify the % of TC that impacts on the prognosis. Methods: We evaluated 610 patients with PTC, divided in: group-A (CV-PTC; 417/610–68.4%), group-B (CV/TC-PTC; 64/610–10.5%) and group-C (TCV-PTC; 129/610–21.1%). Results: No difference were found in the majority of epidemiological and clinical features with the exception of an older age in group-C (p = 0.02). At variance, neoplastic emboli were more frequent in group-B (23.4%) vs C (13.2%) and A (9.8%). Similarly microscopic extra-thyroidal-extension (ETE) was more present in group-C (73.6%) vs B (57.8%) and A (39.6%) (p<0.01). Stage-I was less frequent in group-C (82.2%) vs B (96.9%) and A (94.7%) (p<0.01). Lower activities of 131I were used in group-A (87.1%), vs B (79.7%) and C (74.4%) (p<0.01). After 6 years, we found more structural persistent disease (StR) in group- B (13.1%) vs C (8.9%) and A (4.9%) (p<0.01). Regarding the impact of %TC on the prognosis, only CV/TC-PTC with <10% TC had no StR at the end of follow-up while no major differences in StR was found among cases with a 20-40% of TC (all together 14.5% of StR). Conclusions: the presence of TC, also if <50% but >10% identifies a subgroup of PTC with a biological behavior more similar to TCV-PTC than CV-PTC. Our findings are in line with the indications of the Italian consensus that 10% of TC is enough to define the TCV-PTC.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/1007749
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