99mTc pertechnetate thyroid scan leads to serendipitous detection of metastatic thyroid cancer

99mTc pertechnetate is considered insensitive in detecting thyroid carcinoma metastases. We report the case of a 71-year-old male patient, in whom metastasis of an unknown thyroid cancer was diagnosed incidentally on a routine 99mTc pertechnetate scan, performed for the assessment of nodular thyroid disease. Marked tracer accumulation was unexpectedly noted on the left frontal region, where a palpable, painless, soft tissue mass was present. Surgical excision of the mass revealed metastatic poorly differentiated thyroid carcinoma synchronous to soft tissue and adjacent bone.