Histiocytic sarcoma of the base of tongue treated with radical radiotherapy: A case report and review of the literature

Histiocytic sarcoma (HS) is an exceedingly rare and aggressive neoplasm of lymphoid and haematopoietic tissues and expresses histological and phenotypical characteristics of mature histiocytes. There have only been a few cases of documented HS in the head and neck region. Whilst patients with HS often have nodal or disseminated disease, patients can present with localised disease. There are currently no established treatment guidelines, and reported cases of localised disease have been managed with primary surgery and adjuvant radiotherapy and/or chemotherapy. Here we present, the case of a 49 year old man with a HS of the base of tongue treated with radical radiotherapy to a dose of 60 Gy in 30 fractions, achieving disease free survival of greater than 5 years with minimal toxicity. To our knowledge, this is the first reported case of HS treated with radical radiotherapy, and suggests that when the potential morbidity of surgery for localised disease is significant, radiotherapy may represent an alternative treatment. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of European Society for Radiotherapy and Oncology.