[1] Hosp Especialidades Ctr Med La Raza, Ctr Med Nacl La Raza, Inst Mexicano Seguro Social, Dept Cirugia Gen, Mexico City, DF, Mexico
[2] Inst Mexicano Seguro Social, Hosp Gen Reg 25, Dept Cirugia Gen, Mexico City, DF, Mexico
[3] Inst Mexicano Seguro Social, Hosp Gen Reg 25, Dept Anat Patol, Mexico City, DF, Mexico