Refeeding syndrome is defined as a potentially fatal shift in fluids and electrolytes, which may occur in malnourished patients receiving rehabilitative refeeding. A young man presented with muscle weakness and leg pain. He had adhered to a strict low-carbohydrate, low-calorie diet for five months in preparation for a bodybuilding competition. He ate a large amount of carbohydrate rich foods and consumed water immediately after the competition. Laboratory findings showed hypophosphatemia, hypokalemia, and elevated levels of serum creatine phosphokinase. This case of rhabdomyolysis was caused by refeeding syndrome in a young man who had followed a strictly controlled diet.

Undifferentiated high grade pleomorphic sarcoma of the thyroid gland is very rare. A 70-year-old woman was referred to our hospital for evaluation of a rapidly growing mass in the right lobe of the thyroid gland. At the first visit, she had no symp-toms. Fine-needle aspiration cytology revealed an atypia of undetermined significance. She revisited our hospital after 17 days. At that time the mass had become more enlarged and she complained of dyspnea. The next day, surgery was performed and the diagnosis was undifferentiated high grade pleomorphic sarcoma of the thyroid. The patient died 119 days after sur-gery.