Radiology of the lymphomas

Lymphomas are a group of diseases that provide the radiologist and clinician with unusual challenges. In most cases, an understanding of the histologic classification and staging is essential to design the imaging workup for the patient. Precise staging is critical, particularly for patients with HD and extranodal NHL. The malignant lymphomas share many similar radiographic features, yet have notable differences. An understanding of the pattern of extension of HD is useful in choosing an imaging modality for both staging and follow-up. Contiguous extension of HD follows lymphatic channels and is primarily limited to nodal compartments in the mediastinum and retroperitoneal lymph nodes. On the other hand, NHL may be either widespread or extranodal and localized. In the first instance, the histology will be low grade; in the second, intermediate or high grade. An understanding of these histologic clues is critical to the structuring of an efficient staging workup for the patient with NHL. Posttreatment follow-up imaging strategies should be governed by the fact that in both HD and NHL, recurrences are usually apparent within two years following initial treatment. Treatment complications must be separated from the manifestations of recurrent disease, a particularly important consideration in following up the patient with HD.