PURPOSE: Lymphoma is considered when multiple, nonnecrotic lymph nodes are present in the superficial and deep lymphatic chains, especially if they are large and bilateral, on CT scan. It is reported that combined nodal and extranodal presentation of HD is uncommon. However, we found central low density in involved lymph node of NHL, and combined nodal and extranodal disease in HD, not infrequently. The purpose of this study is to ascertain whether our findings may be characteristics of NHL and HD. MATERIALS AND METHODS: CT findings with contrast enhancement were reviewed in 23 patients with untreated neck lymphoma:18 NHL and 5 HD. The followings were analyzed in each case: nodal or extranodal involvement; unilateral or bilateral involvement; presence or absence of central low density with peripheral enhancement in nodal lesion ;infiltration into adjacent structures. Nodal and extranodal lesions were confirmed by pathologic studies. RESULTS: Of 18 patients with NHL, nine cases had nodal disease and the rest had combined nodal and extranodal disease. Lymphadenopathy was bilateral in ten cases and unilateral in eight. Five cases with HD were composed of three combined nodal and extranodal diseases and two nodal diseases. Central low density of involved lymph node was shown in eight cases of 18 NHL and in one case of five HD. CONCLUSION: Central low density with peripheral enhancement was not uncommon in NHL, in contrast to HD. Hence, it is suggested that in case of nodal necrosis, NHL be also considered, besides tuberculous lymphadenitis and metastatic lymphadenopathy. It is not considered that nodal or extranodal disease, and unilateral or bilateral involvement are of high significance in differentiation of NHL from HD.