Background: Squamous metaplasia may be diagnosed in some diffuse sclerosing variants of papillary carcinoma. Objective- However, bone maturing in the thyroid tumour is a phenomenon that occurs rarely and can mimic a variety of lesions. This study reports such a case in 83 year old man presenting with painless thyroid swelling from last 5 years. Methods: Case study. Conclusions: Osseus metaplasia in diffuse sclerosing variant can be considered as a different subtype because of its aggressive behaviour.