INTRODUCTION

Hodgkin's lymphoma (HL) is a malignant lymphoma. The classical variant (cHL) is characterized by the presence of mononucleated Hodgkin and multinucleated Reed–Sternberg (HRS) cells, while lymphocytic and histiocytic (L&H) cells (“popcorn cells”) are pathognomonic for nodular lymphocyte-predominant HL (NLPHL). After the first description of patients suffering from enlarged lymph nodes and spleen by Thomas Hodgkin in 1832, it took more than 150 years finally to prove the malignant character of these pathognomonic cells and to show their origin from a germinal-center B cell in the majority of cases. Many questions concerning the pathogenesis of Hodgkin's lymphoma are still unanswered; an important step in the pathogenesis of classical HL seems to be the constitutive activation of the NF-κB pathway.

The prognosis of patients with HL depends on the stage of disease and clinical risk factors. The development of stage- and risk-adapted treatment regimens based on modern polychemotherapy and radiotherapy has improved the outcome dramatically over the past few decades. Current strategies aim at reducing therapy-associated complications while maintaining high cure rates.

EPIDEMIOLOGY

HL has an annual incidence of 2–3 per 100 000 in Europe and the USA, and accounts for approximately one-sixth of all lymphoma. Slightly more men than women are affected. In industrialized countries the onset of disease shows a bimodal distribution, with a first peak in the third decade and a second, much smaller, peak after the age of 60.