Introduction

In this relatively uncommon tumor, an infectious etiology has for long been suspected but never confirmed. Remarkable progress has also been made in treatment during the last 25 years which has had a significant effect on mortality rates.

Histology, classification and diagnosis

Hodgkin's disease (HD) is a malignant lymphoma characterized by the presence of multinucleated giant (Reed-Sternberg) cells. There are several histological sub-types and various classifications. The widely used Rye classification describes four sub-types that differ not only morphologically but in their clinical and epidemiological behavior. These four sub-types in order of best to worst prognosis are: lymphocytic predominance, nodular sclerosis, mixed cellularity and lymphocytic depletion (Lukes et al., 1966).

From the epidemiological point of view, three distinct forms of HD have been proposed: a childhood form (0–14 years), a young adult form (15–34 years), and an older adult form (55–74 years). Some authors regard these as separate entities (MacMahon, 1966) while others consider that they result from the interplay of environmental and host factors influencing the natural history of a single disease.

Correa and O'Conor (1971) describe three epidemiological patterns of HD:

Pattern I – is most common in developing countries and is characterized by high rates in male children, low incidence rates in the third decade and a second peak in older age groups. Most cases are classified as mixed cellularity or lymphocyte depletion with poor prognosis.