Central Nervous System Involvement in Primary Nasal Lymphoma.

Nasal NK/T cell lymphoma (NNK/TCL) is a tumor with a low prevalence but is more frequent in Asia and South America. There is no standard treatment for these patients, although radiotherapy is usually recommended. Few reports describe the frequency of central nervous system (CNS) involvement in this type of lymphoma and, in consequence, little is known about the benefit of carrying out screening procedures such as cerebrospinal fluid (CSF) cytology or image studies, nor it is known if prophylactic radiotherapy to the CNS or intrathecal chemotherapy improves the outcome of these patients.

We reviewed the clinical files of 63 patients of the National Cancer Institute in Mexico City with a diagnosis of angiocentric, centrofacial or NNK/TCL between january 1996 and december 2008. We excluded those patients who had a doubtful histopathological diagnosis, who were not completely studied or who did not received treatment in our institution. We collected the following variables: age, gender, histopathological diagnosis, localization of the tumor, clinical stage, symptoms at presentation, IPI score, CNS involvement, CSF cytology, image studies, LDH level, type of treatment and global response to treatment.

We found a total of 48 patients with a diagnosis of primary nasal lymphoma who met the inclusion and exclusion criteria. The mean age was 45.6 (range 16-81) years. The male to female ratio was 2:1. The most frequent localization and histopathological type was the nasal T cell lymphoma (58.3% and 43.8%, respectively). Thirty one percent of the tumors were classified as diffuse large cell and small cell lymphomas due to the lack of immunopathology at the time of diagnosis. Most of the patients were at stage I or II (81.3%) of the disease and had a low or low intermediate IPI score (85.4%). Of the 48 patients 89.6% recieved combined treatment with chemotherapy (CHOP) and radiotherapy, the other 10.4% recieved treatment with radiotherapy alone. Thirty nine point six percent and 23% of the patients had complete and partial response to the treatment, respectively. The remaining patients had either stable or progressive disease. Only 10.9% of the patients complained of neurologic symptoms and 85.4% had a spinal tap done. Nine patients had central nervous system infiltration (18.8%), 55.5% presented with neurological symptoms. Seven of the nine patients with CNS infiltration were diagnosed with a positive CSF cytology (77.8%). Two patients had a negative CSF cytology but had a positive MRI (22.2%). None of these patients had a positive CT scan for CNS involvement. Eight of the nine patients were treated with combined chemo and radiotherapy and 1 patient was treated with radiotherapy alone. Three patients achieved complete response (33.3%). Although there is a great difference in complete response between the patients with and without CNS involvement (6.25% vs 54.17% respectively, p= 0.07), this difference was not statistically significant. This can be due to the small number of patients with CNS involvement. There was no significant difference in the IPI score, LDH levels, stage of the disease or age between the groups.

CNS involvement is present in a considerable proportion of patients with primary nasal lymphoma. Based on these data we think CSF cytology should be done in all patients. The results also suggest that the CT scan is not sensitive enough to detect CNS involvement. The treatment of these patients is an open question because there is virtually no data in the literature regarding therapy for this complication.

No relevant conflicts of interest to declare.