Abstract
The patient was a 2-year-old male with no history of illness. He had been suffering from fever for two days every week four times since one month before admission, and the fever had subsided naturally. He was referred to our hospital because he developed right hip joint pain one day prior to admission. The patient's mother had a history of systemic lupus erythematosus. As the pattern of fever was regular and periodic, and joint pain was observed, periodic fever syndrome was listed as the main potential diagnosis for autoinflammatory disease, and various tests were conducted to consider other rheumatic diseases. Although the CRP level was high, the
patient did not respond well to antimicrobial treatment. A diagnosis of neuroblastoma with bone metastasis was made after a large mass in the retroperitoneum was identified on abdominal CT. Periodic fever syndrome is a relatively recent disease concept that refers to the characteristic pattern of recurrent fever in the context of autoinflammatory diseases. However, this case suggests that a regular fever pattern does not necessarily indicate autoinflammatory disease. As with general cases of fever of unknown origin, if an abdominal ultrasound examination had been performed in addition to a chest radiograph as a screening test from the outset, then an
accurate diagnosis may have been made earlier. Even if the pattern of periodic fever in children is regular, it is necessary to be aware that malignant tumors, including neuroblastoma, should always be included in the differential diagnosis.
