Primary extranodal non Hodgkin's lymphoma of the head and neck in adults: a clinicopathological comparison between tonsillar and non tonsillar lymphomas. (Hellenic co-Operative Oncology Group).

Primary extranodal NHL of the head and neck (HN-NHL) accounts for 10-20% of all cases of NHL. Despite their frequency, the natural history and biological behaviour of these lymphomas is poorly understood. In this study we analysed the data 116 cases of HN-NHL. There were 65 males and 51 females with a median age of 56 years. The distribution among different anatomical sites was: tonsils 56 cases (48.3%), nasopharynx 15 (12.9%), mandible/gingiva 9 (7.8%), hard palate 7 (6%), parotis 6 (5.2%), nasal cavity 6 (5.2%), hypopharynx/larynx 6 (5.2%), thyroid 5 (4.3%), ocular adnexa 4 (3.5%), paranasal sinuses 2 (1.7%). The patients were treated with radiotherapy alone (14 cases), combined chemotherapy (52 cases) and combined modality (50 cases). According to the WF histological classification 73 cases (62.9%) had intermediate, 32 (27.6%) high and 11 (9.5%) low grade. Patients were separated in two groups: Tonsillar NHL (56 cases) and NHL of all other sites (non-tonsillar group-60 cases). A comparison between the two groups showed that there was no statistically significant difference with respect to age, sex, and histological subtypes. Also treatment response was similar (82.1% for the tonsillar vs 83.3% for the non-tonsillar). The two groups differed in stage distribution, survival and pattern of relapse. Stage I was more frequent in the non-tonsillar NHL (60%) in contrast to tonsillar NHL where stage II was more prominent (51.8%). Median survival was 86 months for the tonsillar while it has not been reached yet for the non-tonsillar patients. Patients in stage I and stage II of the non-tonsillar group had better survival compared to stages I and II of the tonsillar patients. Finally GI tract was a common site of relapse in the tonsillar group while a considerable number in CNS relapses were observed in the non-tonsillar group. We concluded that HN-NHL constitutes a heterogeneous group of patients. Tonsillar lymphomas represent a distinct group with some special clinicopathological findings.