CT images of 24 patients with head and neck lymphoma were retrospectively reviewed, compared with ultrasonograms, and compared with CT images of 13 patients with lymph node metastases. In nine (38%) of 24 patients, some lymph nodes with lymphomatous involvement showed a spotty or linear pattern of contrast enhancement. In two of these nine patients, a dendritic pattern of contrast enhancement between multiple enlarged lymph nodes was observed. The same pattern appeared as spotty, linear, or dendritic hyperechoic areas on the ultrasonogram. None of 13 patients with lymph node metastases showed a spotty, linear, or dendritic pattern of contrast enhancement. Ten of 13 (77%) showed ring-like contrast enhancement on CE-CT images. The spotty or linear contrast enhancement in enlarged lymph nodes and the dendritic contrast enhancement in confluent lymph nodes could be useful CT findings in diagnosing nodal involvement with malignant lymphoma.