Circulating Hodgkin cells: A clinicopathologic analysis of seven patients and a review of the literature

Abstract Introduction Hodgkin cell leukemia is a rare phenomenon in which Hodgkin and Reed‐Sternberg cells circulate the peripheral blood. Few cases were reported but no modern case series is available in the literature. Methods Peripheral blood smears from patients diagnosed with Hodgkin lymphoma (HL) at our institution were reviewed. Relevant clinical and pathologic parameters were collected and compared with reported cases in the literature. Results Seven patients were identified over a period of 8 years. All patients were males with a median age of 35 years. The diagnosis was classic HL in six (86%) patients and nodular lymphocyte predominant in one (14%). All patients presented with anemia (100%), and six (86%) had leukopenia and lymphopenia. Circulating Hodgkin cells were few in number and ranged between 2% and 10% of total white blood cells. Mononuclear Hodgkin cells were more common than binucleated Reed‐Sternberg cells. All patients were in stage IV disease (100%). Six patients (86%) died within one year of identifying these cells. Conclusions Hodgkin cell leukemia is very rare and represents a terminal event in the course of the disease of any histologic subtype. It is strongly associated with poor prognostic factors of HL such as advanced clinical stage, male gender, and the presence of anemia and lymphopenia. Circulating Hodgkin cells are few in number and thus can be missed in routine blood film examination. We describe the morphologic features of leukemic Hodgkin cells in details in order to help pathologists identify them for both diagnostic and research purposes.