Extranodal natural killer/T-cell lymphoma, nasal type (NK/TCL) is more prevalent in Asia and in some areas of South and Central America, but it is rarely seen in the United States and Europe. In this study, a series of 122 cases of NK/TCL from Brazil was analyzed with respect to clinicopathologic features. Clinical characteristics and geographic distribution were evaluated in 97 cases of nasal/nasopharyngeal region and 23 cases in extranasal sites including 6 nodal cases. Clinical staging and follow-up information was available in a subset of 21 patients. All cases harbored Epstein-Barr virus (EBV), 95% and 85% expressed cytoplasmic CD3 and CD56, respectively, and all cases were positive for at least 1 marker for cytotoxic granules. The global distribution of EBV subtypes showed predominance of strain subtype A, 89%, and subtype B, 11%. No dual infections were detected. TCR-γ TCR-gene rearrangement was observed in 7 cases; all of them extranodal. Three of TCR-γ+ cases showed EBV subtype A. Two TCR-γ+/CD56+ cases showed EBV subtype B. Geographic distribution of NK/TCL showed higher frequency in the southeast and northeast regions of Brazil. Striking differences among geographic regions were seen with the vast majority of EBV subtype B (86%) occurring in the south and southeast regions.
*Consultoria em Patologia, Botucatu, SP, Brazil
†University of Miami Miller School of Medicine and Sylvester Cancer Center, Fogarty International Center, Miami, FL
‡Department of Pathology, Stanford University School of Medicine, Stanford, CA
Correspondence: Carlos E. Bacchi, MD, PhD, Consultoria em Patologia, Rua Major Leônidas Cardoso 739, Botucatu, SP, 18602-010, Brazil (e-mail: firstname.lastname@example.org).