Tall cell carcinoma with reversed polarity of the breast: a case report Running title: Tall cell carcinoma with reversed polarity of the breast

Tall cell carcinoma with reversed polarity (TCCRP) of the breast is a rare malignant neoplasm that shares morphological similarities with the tall-cell variant of papillary thyroid carcinoma, which may lead to diagnostic confusion. Immunohistochemical and molecular analyses are essential to confirm mammary origin and exclude metastatic thyroid carcinoma. Herein, we report a case of a 62-year-old woman, who was diagnosed with TCCRP based on characteristic histomorphological features and immunohistochemical findings in a breast mass. Despite exhibiting a triple-negative immunophenotype, TCCRP is associated with an indolent clinical course. Accurate diagnosis requires integration of morphological, immunohistochemical, and molecular features, which are critical for appropriate classification and may help support a more conservative management approach.