Table 3.
Clinicopathological characteristics according to the WHO 2017 classification
| MI-FTC | EA-FTC | WI-FTC | p for trend | |
|---|---|---|---|---|
| Age, years (mean ± SD) | 39.7 ± 13.1 | 42.5 ± 18.4 | 50.8 ± 14.8 | 0.063* |
| Sex | ||||
| Female | 38 (80.9) | 17 (68.0) | 12 (80.0) | 0.651 |
| Male | 9 (19.9) | 8 (32.0) | 3 (20.0) | |
| Size | ||||
| Mean, cm (mean ± SD) | 3.2 ± 1.5 | 4.0 ± 1.7 | 4.9 ± 3.4 | 0.063* |
| ≤ 2 cm | 9 (19.1) | 1 (4.0) | 5 (33.3) | 0.688 |
| > 2 cm and ≤ 4 cm | 25 (53.2) | 14 (56.0) | 4 (26.7) | |
| > 4 cm | 13 (27.7) | 10 (40.0) | 6 (40.0) | |
| Surgical extent | ||||
| Total or subtotal thyroidectomy | 23 (48.9) | 22 (88.0) | 15 (100.0) | < 0.001 |
| Lobectomy | 24 (51.1) | 3 (12.0) | 0 (0.0) | |
| Gross ETE | ||||
| Absent | 47 (100.0) | 24 (96.0) | 13 (86.7) | 0.017 |
| Present | 0 (0.0) | 1 (4.0) | 2 (13.3) | |
| Initial distant metastasis | ||||
| Absent | 47 (100.0) | 23 (92.0) | 9 (60.0) | < 0.001 |
| Present | 0 (0.0) | 2 (8.0) | 6 (40.0) | |
| TERT promoter mutations | ||||
| Wild-type | 42 (89.4) | 20 (80.0) | 9 (60.0) | 0.013 |
| Mutation | 5 (10.6) | 5 (20.0) | 6 (40.0) | |
| AJCC/TNM 8th stage | ||||
| I | 47 (100.0) | 19 (76.0) | 8 (53.3) | < 0.001 |
| II | 0 (0.0) | 4 (16.0) | 6 (40.0) | |
| III/IV | 0 (0.0) | 2 (8.0) | 1 (6.7) | |
Data are expressed as n (%) unless otherwise specified
SD standard deviation, WHO World Health Organization, MI-FTC minimally invasive FTC, EA-FTC encapsulated angioinvasive FTC, WI-FTC widely invasive FTC, FTC follicular thyroid carcinoma, ETE extrathyroidal extension, TERT telomerase reverse transcriptase, AJCC/TNM American Joint Committee/Tumor-Node-Metastasis
*p for trend for continuous variables was analyzed using the Jonckheere–Terpstra test