Nasal/Nasal Type NK/T-Cell Lymphoma: A Brazilian Experience of 40 Cases.

NK/T nasal type lymphoma is a rare type of non-Hodgkin’s lymphoma with a peculiar geographical distribution. Most of the reported cases come from Asian coutries and native populations from Latin America, such as Peru, Guatemala and Mexico. It is rarely reported in Brazilian population. We retrospectively studied 40 cases of Nasal/Nasal type NK/T-cell Lymphoma diagnosed at our center, between 1979 and 1999. Patient characteristics were as follows: 18 white,13 mulatto, 6 Asian and 3 black; 28 men and 12 women; median age 42.8 years (range 17–78). Patients originaly from all Brazilian geopolitical regions were present. One or more structures of the mild-facial region were involved in all cases, mainly in the nasal cavity (38 cases), ethmoidal sinus (21 cases), maxillary sinus (20 cases), palate (20 cases), nasopharingeal (13 cases), nose flap (11 cases), orbita (11 cases), sphenoidal sinus (9 cases), frontal sinus (6 cases), oropharingeal (3 cases). The most frequent symptoms were:nasal obstruction(27 cases), palate ulcer or edema(18 cases), fetid odor(14 cases), rhinorrehoea (9 cases), and orbital edema(8 cases). Considering the stage, 32 patients were in stage IE, 5 in stage IV, 1 in stage IIE and for 2, the stage was unknown. The median time from the onset of symptoms to diagnosis was 5.5 months, ranging between 1 and 17 months. The number of biopsies to confirm the diagnosis ranged between 1 and 5, with a median of 2 biopsies. Diagnosis was based on histological examination, immunohistochemistry panel(CD20, CD2, cCD3, CD43, CD45RO, CD16, CD56, granzin-B, TIA-1 and p53), in situ hybridization(ISH)forEBV and PCR for TCR gamma chain gene rearrangement. Important histological features were necrosis in almost all cases(38 cases) and angiocentricity and angioinvasion in 32 cases. There was no clear association between necrosis and angiocentricity, suggesting that other causes can be involved in the pathogenesis of the necrosis. Association between EBV and the pesence of necrosis in the histological study was present. Most of the cases showed a phenotypical and genotypical profile of NK cell lineage. Two cases presented monoclonal rearrangement for TCR gamma chain gene, characterizing T cell lineage. The only two cases of T cell lineage were also negative for EBV. Immunohistochemical reativity for p53 was observed in 24 cases. There was no association between the progression of the disease and the immunoexpression for p53. Most of the patients were treated with chemotherapy alone(14 cases) or associated with radiotherapy(20 cases). One patient was treated with radiotherapy alone and 5 patients were not treated due to a rapid progression to death. The overall median survival time was 12.6 months. The cause of death could be assessed in 23 patients;15 died due to infectious complications, and septicemia was the most frequent cause. The results of this retrospective survey confirmed that Nasal/Nasal type T/NK-cell Lymphoma is characterized by a very bad prognosis. More data are needed to know the epidemiology of this rare lymphoma in South America. The results show that EVB is also highly associated with this lymphoma in Brasilian patients.