[en] We examined malignant lymphomas and polymorphic reticulosis of nasal cavity, nasopharynx, and palate, diagnosed at Korea Cancer Center Hospital from 1987 to 1996. With immunophenotypic study, we reclassified nasal/nasopharyngeal lymphomas into three categories: CD56-positive T/NK lymphoma, CD56-negative lymphoma and B-cell lymphoma. Malignant lymphomas of nasal cavity, nasopharynx and palate were 95 patient, that comprised 11% of the total lymphoma cases, and it was the most common extranodal lymphoma. Twenty-five percent were B-cell lymphomas and 75 % were T/NK lymphomas. According to site, nasal cavity was the most frequent and 91 % of nasal cavity lymphomas were T/NK type. CD56-positive T/NK comprised 82 % of total T/NK lymphomas and CD56-negative cases were 18 %. In 89 % of total T/NK lymphomas, many tumor cells expressed EBER-1 in their nuclei (CD56+ T/NK lymphoma: 97 % of EBV expression, CD56-T-cell lymphoma; 60%). Only one case (5%) of B-cell lymphoma showed EBER-1 positivity in a few cells. CD56+ T/NK lymphomas showed significantly more angiocentricity and severe necrosis than CD56- cases. Although it has no statistical significance, T/NK lymphomas has a tendency to lower survival rates than B-cell lymphomas at 1 year and 2 year. CD56+ T/NK lymphomas has a tendency to lower survival than CD56- T/NK lymphomas (p > 0.05). Our results of this project will serve important basic materials in diagnosing and studying lymphoma. (author). 25 refs., 4 tabs., 4 figs