[1] Inst Nacl Cancerol, Dept Head & Neck Surg, Mexico City, DF, Mexico
[2] Hosp Gen Manuel Gea Gonzalez, Dept Gen Surg Head & Neck, Mexico City, DF, Mexico
[3] Inst Nacl Cancerol, Dept Pathol, Mexico City, DF, Mexico
[4] IMSS, Ctr Med Occidente, Guadalajara, Jalisco, Mexico