A 63-year-old female was admitted to our hospital with a tender abdominal wall mass about 15 cm in diameter, which she had for 1 month. About 1 week earlier, the patient had also perceived a mass in the neck area. Computed tomography revealed huge thyroid and periumbilical masses. The thyroid hormone levels were consistent with a hyperthyroid state. Pathological examination of the thyroid mass was compatible with anaplastic thyroid carcinoma (ATC) and the abdominal cutaneous mass was shown to be metastatic ATC. Despite palliative radiotherapy and chemotherapy, the patient died of respiratory failure on her 63rd day of hospitalization. This case demonstrates that abdominal cutaneous metastasis and hyperthyroidism can occur as initial manifestations of ATC. To our knowledge, this is the first reported case.