An apparatus is provided for stapling tissue. The apparatus includes an anvil and a trocar selectively coupled with the anvil. The anvil may have an inner opening and a plurality of staple pockets aligned around a surface of the anvil. The anvil may be inserted trans-orally through an esophagus prior to being coupled with the trocar. The trocar may include a shaft and a locking assembly. The locking assembly may secure the anvil in position relative to the trocar when the locking assembly is in the expanded position. The apparatus may also include an alignment assembly to align the staple pockets of the anvil relative to the apparatus. The apparatus may also include an introduction assembly to guide the anvil through the esophagus.