NIFT-P: Are they indolent tumors? Results of a multi-institutional study.
Résumé
Background
Encapsulated follicular variant of papillary thyroid carcinoma has recently been reclassified as noninvasive follicular thyroid neoplasm with papillary-like nuclear features on the basis of its highly indolent behavior, as proposed by an international group of experienced thyroid pathologists.
Methods
All patients from 9 high-volume endocrine surgery departments who underwent surgery between 2005 and 2015 and whose final surgical pathology revealed noninvasive follicular thyroid neoplasm with papillary-like nuclear features (>10 mm) were included in this study. The primary outcome was to determine the potential for recurrent disease in these patients.
Results
Among the 363 patients with noninvasive follicular thyroid neoplasm with papillary-like nuclear features, 76% were female with a median age of 50 years (5–86 years); 345 patients (95%) underwent total thyroidectomy. A total of 65 patients had an associated micropapillary thyroid carcinoma. In the group of 133 patients who underwent prophylactic lymph node dissection (37%), 1 patient had a micrometastasis but with an associated micropapillary thyroid carcinoma. Over a median follow-up period of 5 years, 1 patient with an associated micropapillary thyroid carcinoma had recurrent disease at 6 years. All patients with noninvasive follicular thyroid neoplasm with papillary-like nuclear features without micropapillary thyroid carcinoma had no lymph node metastasis or recurrent disease.
Conclusion
We found that noninvasive follicular thyroid neoplasm with papillary-like nuclear features presents with indolent behavior. However, the identification of an associated micropapillary thyroid carcinoma should be carefully evaluated because it could be a factor for lymph node metastasis and/or of recurrence.