Multinucleated giant cells in papillary thyroid carcinoma

Abstract

Objectives : We studied the significance of multinucleated giant cells (MGCs) in papillary carcinoma of the thyroid, which has received little attention in Japan.
Study Design : Cases were 50 aspiration biopsy specimens of the thyroid, histologically diagnosed as papillary carcinoma. Cases of adenomatous goiter, Hashimoto’s thyroiditis, and undifferentiated carcinoma were selected as control cases.
Results : MGCs observed in 21 of the 50 specimens were classified in MGCs with dense cytoplasm and MGC with foamy cytoplasm. MGCs with dense cytoplasm contained over 10 to 20 nuclei and cytoplasm stained light green. MGCs with foamy cytoplasm were oval in shape. Both types were positive for CD68, suggesting histiocyte origin. Control cases showed only MGCs with foamy cytoplasm and no MGCs with dense cytoplasm except for one case of undifferentiated carcinoma.
Conclusion : MGCs with dense cytoplasm were found in 42% cases of papillary carcinoma of the thyroid. It can be a useful ancillary finding since very few diseases show MGCs with dense cytoplasm except for papillary carcinomas. The finding of MGCs with dense cytoplasm in daily cytology specimens necessitates considering the possibility of papillary carcinoma and attention to nuclear findings in that specimen.