Complete response after chemotherapy and radiotherapy of a tonsillar histiocytic sarcoma with regional lymph node involvement: a case report and review of the literature.

We describe a case of tonsillar histiocytic sarcoma (HS) with regional lymph node involvement and complete response after multi-disciplinary therapy. Immunohistochemistry showed strong positive tumor staining for CD 68, and negative staining for CD20, CD45R0 and CD30 and non-cohesive proliferation of neoplastic histiocytes. Systemic chemotherapy with cyclophosphamide, doxorubicin, vincristine, prednisone, and etoposide (CHOP-E) chemotherapy followed by radiotherapy was delivered to the patient. No evidence of recurrent disease existed on regular follow up three years later. The diagnostic methods and the practical treatment solutions are discussed here. We believe that although HS has been regarded as a potentially fatal disease entity, there remain some cases that do not pursue such an aggressive clinical course.