Malignant neoplasia of the paranasal sinuses associated with mucocele.

Paranasal sinus mucoceles are histologically benign and typically cause ophthalmic morbidity only after significant orbital extension. The authors describe seven patients who had both a mucocele and a malignant tumor in the same paranasal sinus and in whom the neoplasm was discovered incidentally during operation for mucocele. Although malignancy coexistent with paranasal sinus mucocele is uncommon, the association should be considered and appropriate biopsy specimens obtained if operation for mucocele is required.