Table 5.
Impact of NIFTP on the risk of malignancy in FNAC diagnostic categories in histology-proven cases
| FNAC diagnostic category | No. | No. of malignancy including NIFTP (%) | No. of malignancy excluding NIFTP (%) | Absolute decrease in ROM (%) | Relative decrease in ROM (%) |
|---|---|---|---|---|---|
| Non-diagnostic | 73 | 48 (65.8) | 47 (64.4) | 1.4 | 2.1 |
| Benign | 54 | 18 (33.3) | 13 (24.1) | 9.2 | 27.6 |
| AUS | 306 | 232 (75.8) | 218 (71.2) | 4.6 | 6.1 |
| AUS-NA | 215 | 191 (88.8) | 182 (84.7) | 4.1 | 4.6 |
| AUS-MF | 53 | 28 (52.8) | 23 (43.3) | 9.5 | 18.0 |
| AUS-HC | 17 | 1 (5.9) | 1 (5.9) | 0 | 0 |
| AUS-others | 21 | 12 (44.4) | 12 (44.4) | 0 | 0 |
| Follicular neoplasm | 27 | 10 (37.0) | 8 (29.6) | 7.4 | 20.0 |
| Suspicious for malignancy | 393 | 390 (99.2) | 387 (98.5) | 0.7 | 0.7 |
| Malignant | 1,038 | 1,038 (100) | 1,038 (100) | 0 | 0 |
| Total | 1,891 | 1,736 (91.8) | 1,711 (90.5) | 1.3 | 1.4 |
NIFTP, noninvasive follicular thyroid neoplasm with papillary-like nuclear features; FNAC, fine needle aspiration cytology; ROM, risk of malignancy; AUS, atypia of undetermined significance; NA, nuclear atypia; MF, microfollicles; HC, Hurthle cells.