Clinicopathological features of classical Hodgkin lymphoma in patients ≥40 years old, with special reference to composite cases

OBJECTIVE: Classical Hodgkin lymphoma shows a peak incidence at 15-35 years, and a second peak in elderly patients; however, pathological characteristics of elderly patients with classical Hodgkin lymphoma have not been analyzed enough. METHODS: In a total of 154 patients with classical Hodgkin lymphoma, we analyzed the clinicopathological characteristics of classical Hodgkin lymphoma patients aged ≥ 40 years old, with special reference to the incidence, histopathology and outcome of patients with composite classical Hodgkin lymphoma. RESULTS: Of 154 patients with classical Hodgkin lymphoma, 50 (32%) were ≥ 40 years old. The 5-year progression-free and overall survival rates were 59 and 86%, respectively. Thirty-eight patients (76%) had non-composite classical Hodgkin lymphoma, 10 patients (20%) had composite (6 simultaneous and 4 consecutive) classical Hodgkin lymphoma and B-cell non-Hodgkin lymphoma and 2 patients (4%) had methotrexate-associated classical Hodgkin lymphoma. Of 10 patients with composite classical Hodgkin lymphoma, composite lymphomas were detected throughout the staging procedure of the upper gastrointestinal tract or bone marrow in 4 patients. Fluorescence in situ hybridization revealed that the composite lymphomas of 4, 1 and 5 patients were related, unrelated and of unknown correlation status, respectively. The treatments after the diagnosis of a classical Hodgkin lymphoma component varied, and three patients died of lymphoma. CONCLUSIONS: We found that the incidence of composite classical Hodgkin lymphoma in patients ≥ 40 years old was 20%. Correct diagnosis and optimal treatment for patients with composite classical Hodgkin lymphoma and B-cell non-Hodgkin lymphoma is highly important in this patient population.