Macrofollicular Variant of Papillary Thyroid Carcinoma with Extensive Hemorrhage / 대한세포병리학회지

ABSTRACT

BACKGROUND: The macrofollicular variant of papillary thyroid carcinoma (MVPC) is characterized by macrofollicles occupying more than half of the tumor and demonstrating nuclear features of classic papillary carcinoma. It is difficult to recognize on fine needle aspiration (FNA) cytology due to the paucity of aspirated neoplastic cell clusters, especially when the tumor is associated with extensive areas of hemorrhage. CASE: A 34-year-old female presented with a well-demarcated nodule in the thyroid gland, diagnosed as a benign nodule on ultrasonography and computed tomography. FNA cytology smear revealed a few small aggregates of follicular cells with morphological features suspicious for papillary carcinoma, set in a background of hemorrhage, inflammatory cells, and hemosiderin-laden macrophages. Intraoperative frozen section revealed macrofollicular nests filled with hemorrhage and composed of follicular cells demonstrating nuclear clearing and grooves. CONCLUSION: MVPC is a rare but distinctive variant of papillary carcinoma, which is easily mistaken for adenomatous goiter or benign macrofollicular neoplasm on radiologic findings. The cytopathologist should alert oneself on encountering benign radiologic findings and any smear composed of scant numbers of follicular cells with nuclear features suspicious for papillary carcinoma despite the bland-looking background of hemorrhage and hemosiderin-laden macrophages, and recommend intraoperative frozen sections for a definite diagnosis.