Spontaneously regressed Langerhans cell histiocytosis of lymph nodes in an elderly patient

Langerhans cell tumors are neoplastic proliferation of Langerhans cells and are classified into Langerhans cell histiocytosis (LCH) and Langerhans cell sarcoma (LCS). We report a case of LCH in an 89-year-old-woman with left axillary lymphadenopathy. A histologic examination demonstrated a proliferation of histiocytoid cells which were positive for CD1a, S-100 protein, and Lagerin (CD207). Initial diagnosis was LCS based on morphologic features, high MIB-1 index, and multi-system involvement detected by FDG-PET. However, the disease disappeared spontaneously without specific treatment in six months. The disease was considered to be spontaneously regressed LCH with multi-system involvement rather than LCS.