Case Report: The clear cell variant of papillary thyroid carcinoma: a clinicopathologic study of four cases with emphasis on RET gene fusions.
NCOA4-RET gene fusion found in half of clear cell papillary thyroid carcinoma cases
Case Report: The clear cell variant of papillary thyroid carcinoma: a clinicopathologic study of four cases with emphasis on RET gene fusions.
The clear cell variant of papillary thyroid carcinoma (clear cell variant of papillary thyroid carcinoma) is an exceedingly rare and diagnostically challenging subtype of papillary thyroid carcinoma (papillary thyroid carcinoma), defined by distinctive histomorphologic features.
Here, we aimed to delineate the clinicopathologic, immunohistochemical, and molecular genetic characteristics of clear cell variant of papillary thyroid carcinoma by retrospectively analyzing four pathologically confirmed cases diagnosed at our institution between 2018 and 2025, together with a comprehensive review of the published literature.
NCOA4-RET fusion present in half the tumors tested
The male to female ratio of the four clear cell variant of papillary thyroid carcinoma cases is 1: 3, with a median age of 60 years (range 45-68) and presented clinically with thyroid nodules.
Histopathological evaluation demonstrated infiltrative tumor growth patterns with solid, trabecular, and focal papillary architectures.
Lymph node metastases were observed in three cases.
Immunohistochemical profiling revealed consistent positivity for TTF-1, Pax8, CK7, thyroglobulin (thyroglobulin) and Galectin-3, and absence of expression for TPO, BRAF V600E mutation, and various neuroendocrine markers.
The detection of an NCOA4-RET fusion in half of our cases suggests a recurrent genetic alteration that may contribute to its pathogenesis, though this finding requires validation in larger cohorts.