A 28 year old male presents with ophthalmoplegic signs of thyrotoxicosis. All of the following can be considered in the differential diagnosis of the case, EXCEPT:

Riedel's Thyroiditis is the rarest type of thyroiditis characterized by replacement of all or pa of the thyroid parenchyma by fibrous tissue, which also invades into adjacent tissue. As the thyroid tissue is replaced by fibrous tissue it may present with hypothyroidism but never with hypehyroidism. "Riedel's Thyroiditis is one condition where hypehyroidism is not seen, not even transiently". Ref: Schwaz 9/e, Page 1357; Harrison 17/e, Page 2239; CMDT, 2005, Page 1111.