Langerhans cell sarcoma arising from antecedent langerhans cell histiocytosis: A case report.

Langerhans cell sarcoma (LCS) is a rare, high-grade neoplasm characterized by overtly malignant cytologic features and a poor prognosis. Herein, we present a rare case of langerhans cell histiocytosis (LCH) that later transformed into langerhans cell sarcoma 11 months after the benign mass was excised from soft tissue in the right groin.A 41-year-old patient who presented with a mass in the right groin for 3 years earlier after being bitten by ants.The patient was diagnosed with langerhans cell sarcoma arising from antecedent langerhans cell histiocytosis.The patient underwent with 6 cycles of a modified etoposide, cyclophosphamide, vindesine, dexamethasone (E-CHOP) regimen.The patient is currently receiving follow-up care.LCH transformed into LCS is a rare case. E-CHOP as an effective first-line therapy to treat LCS cases, but, the mechanism is unclear. Due to their rarity, further data on clinical outcomes are necessary to establish the optimal treatment strategy for LCS.