摘要: Abstract 1. Carcinoma arising from the mucous membrane of maxillary sinus is not always associated with roentgenologically demonstrable destruction bone. 2. Large cysts may be attended by bone typical carcinoma. 3. The mucosa in a cyst undergo malignant degeneration. 4. In presence tumor, only histologic examination can establish diagnosis certainty. Hence, if there slightest suspicion degeneration cystic mucosa, should never omitted.