Late recurrences of histiocytic lymphoma after treatment

Disease-free intervals of 2 to 3 years after treatment of histiocytic lymphoma are generally thought to represent cures; flat survival curves beyond 3 years in several studies support this notion. Four case reports of histiocytic lymphoma recurrences 25, 10, 9 and 6 years, respectively, after the initial diagnosis are presented. Histologic confirmation comparing primary and recurrent disease is presented. The potential biological significance of such patient reports is discussed.