Malignant neoplasm of pyriform sinus

**Inclusion terms:** - Malignant neoplasm of pyriform fossa

**Use additional code:** - code to identify: - exposure to environmental tobacco smoke (Z77.22) - exposure to tobacco smoke in the perinatal period (P96.81) - history of tobacco dependence (Z87.891) - occupational exposure to environmental tobacco smoke (Z57.31) - tobacco dependence (F17.-) - tobacco use (Z72.0)