Ultrastructure of anaplastic carcinoma (spindle and giant cell type) with large calcification in the thyroid gland

Calcification is rare in undifferentiated thyroid carcinoma, because of it's rapid progress. We report here such a case seen in a 73-year-old male who terminated from pulmonary metastases 4 months after initial diagnosis of spindle and giant cell carcinoma of the thyroid gland.