Abstract
Langerhans cell histiocytosis (LCH) is a rare inflammatory neoplasia characterized by infiltration of monoclonal LCH cells; it is more common in children than in adults. Even after achievement of complete remission, there is concern that this disease can cause permanent consequences or secondary malignancies, thereby reducing quality of life. Herein, we report a patient with multifocal bone LCH who developed papillary thyroid carcinoma (PTC) after complete remission of LCH. The patient, a 15-year-old male, had LCH lesions on the right temporal bone and left femur at 9-year-old. He received chemotherapy according to Japan LCH Study Group (JLSG)-02 protocol, and obtained complete remission. However, five years later, he developed PTC with bilateral lymph node metastases; he underwent a total thyroidectomy and bilateral neck dissection. Both LCH and PTC lesions were positive for BRAF V600E mutation. To date, 13 years after the onset of LCH, he is alive in remission of both LCH and PTC. Because ear lesions are often observed in LCH and a close relationship between LCH and papillary thyroid cancer has been noted, otolaryngologists should be familiar to diagnosis and long-term complications of LCH.
