Evaluation of malignancy risk and endoscopic follow up in achalasia: Case report - AKYÜZ, Filiz; İBRİŞİM, Duygu; BALIK, Emre; YÖNAL, Oya; KAYMAKOĞLU, Sabahattin; BUĞRA, Dursun; MUNGAN, Zeynel (Turkish Journal of Gastroenterology, 2006)