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Purpose: To prospectively determine the diagnostic accuracy of diffusion-weighted magnetic resonance (MR) imaging for discrimination of malignant neck nodes due to lymphoma, squamous cell carcinoma (SCC), and undifferentiated nasopharyngeal carcinoma (NPC), with histologic findings and imaging criteria as reference standards., Materials and Methods: Ethics committee approval and informed consent were obtained. Patients with malignant lymphadenopathy underwent 1.5-T diffusion-weighted MR imaging. A region of interest was drawn around the malignant node on apparent diffusion coefficient (ADC) maps; ADC values were compared (Kruskal-Wallis test). Receiver operating characteristic analysis was employed to investigate whether ADC values could aid in discrimination among malignancies., Results: Forty-three patients (34 men, nine women; mean age, 54 years) with 43 nodes underwent imaging. Mean ADC values for lymphoma (n = 8), NPC (n = 17), and SCC (n = 18) were (0.664 +/- 0.071 [standard deviation]) x 10(-3) mm(2)/sec, (0.802 +/- 0.128) x 10(-3) mm(2)/sec, and (1.057 +/- 0.169) x 10(-3) mm(2)/sec, respectively, with significant differences between SCC and lymphoma or NPC (P < .001) and between NPC and lymphoma (P = .04). To optimize sensitivity and specificity with equal weighting, ADC threshold values for distinguishing between SCC and NPC, between SCC and lymphoma, and between NPC and lymphoma were 0.894 x 10(-3) mm(2)/sec, 0.824 x 10(-3) mm(2)/sec, and 0.694 x 10(-3) mm(2)/sec, respectively. To produce a 100% specificity while sensitivity is maximized, the following ADC threshold values were obtained for prediction of differentiation between malignancies: (a) SCC versus lymphoma, greater than 0.824 x 10(-3) mm(2)/sec (sensitivity, 94%), and lymphoma versus SCC, less than 0.767 x 10(-3) mm(2)/sec (sensitivity 88%); (b) NPC versus SCC, less than 0.764 x 10(-3) mm(2)/sec (sensitivity, 47%), and SCC versus NPC, greater than 1.093 x 10(-3) mm(2)/sec (sensitivity, 39%); (c) NPC versus lymphoma, greater than 0.788 x 10(-3) mm(2)/sec (sensitivity, 53%), and lymphoma versus NPC, no suitable threshold value., Conclusion: Diffusion-weighted MR imaging shows significant differences among malignant nodes of SCC, lymphoma, and NPC. ADC threshold values can help distinguish SCC from lymphoma., Supplemental Material: http://radiology.rsnajnls.org/cgi/content/full/2451061804/DC1.

Primary nasal lymphoma (NSL) and nasopharyngeal lymphoma (NPL) are uncommon extranodal lymphomas that have often been grouped together in studies published in the literature. It is unclear whether or not NSL and NPL are biologically different entities. We reviewed the records of 25 NSL and 19 NPL patients who were managed between 1985 and 1995, to evaluate and compare their clinical characteristics and treatment outcome. Clinical variables, including age, sex, stage, tumour bulk and treatment modality, were assessed for their prognostic influence on survival. Nasal obstruction (80%), nasal discharge (64%) and epistaxis (60%) were the predominant symptoms in NSL patients; neck swelling/mass (42%), nasal obstruction (37%) and hearing impairment (32%) were common findings in NPL patients. Limited stage disease (I/II) was present in all NSL and in 80% of the NPL patients. Thirty-six per cent of the NSL and 32% of the NPL patients had bulky disease. The majority of the immunophenotyped NSLs were of T-cell lineage (75%, 12/16) and most immunophenotyped NPLs were of B-cell lineage (69%, 11/16). The patients were treated with radiotherapy alone (14%), chemotherapy alone (23%) or chemotherapy plus radiotherapy (64%). NSL patients showed a lower complete remission rate and higher relapse rate than NPL patients, although the difference did not reach statistical significance. Both the 5-year disease-free survival (36% versus 76%; P = 0.007) and overall survival (33% versus 82%; P = 0.003) were significantly worse in NSL compared with NPL patients. Advanced age (>60 years; P = 0.03) and bulky disease (P = 0.04) were also associated with inferior survival times. The analysis of sex, stage and type of therapy showed no evidence of significant impact on the survival. Despite the close anatomical relationship in origin, NSL and NPL were noted to behave as biologically distinct entities, in which the NSLs demonstrated a higher frequency of T-cell tumours and a much worse prognosis than NPL. In addition to the primary site, advanced age and bulky disease were also associated with reduced survival.