Radiologic changes in the formation of frontal sinus - muco-pyocele

The history, the gradual evolution of soft tissue changes as revealed by roentgenography and the gross and microscopic changes in the lining muco‐periosteums of two frontal sinuses which had been resected surgically, are presented. On the basis of these reports and that of past experience, the following generalizations in respect to these two cases seem valid: 1. Radiographic mucosal changes in a frontal sinus may exist months or years without subjective symptoms. 2. Obstruction of the fronto‐nasal opening with a subsequent gradually progressive increase in volume and pressure of the fluid contents of the sac or sinus, may eventually result in pressure absorption of the bony walls of the sinus. 3. A mucocele does not cause sudden or acute symptoms, such as pain or fever, but objective signs such as a soft swelling above the eyebrow or the dislocation of the globe in the orbit, may appear and slowly increase. 4. When in the presence of acute infection of the upper respiratory tract acute subjective or objective frontal sinus symptoms and signs become evident without previously recalled sinus disease or trauma and where prior radiographic study of the area has not been made, one cannot be certain that slowly developing changes of the sinal muco‐periosteum have not been present for a long time, and such pre‐existing disease might not have led to confused interpretation of the radiologic pictures, to misinterpretation of symptoms and signs and to a faulty diagnosis. 5. The variation in the mucosal histological findings and sac or contents noted at the time of surgery will be those related to the nature of the causative or related organism, the degree of activity, the development time factor or duration of the condition, the effect of pressure on soft tissue surrounded by bone, and the circumstances precipitating the need for surgical treatment. 6. Regardless of the origin, the muco‐pyocele of many years' duration under constant slowly expanding pressure may eventually result in sterile contents and loss of the original identity of the mucosal structure, making an exact disease classification difficult or impractical. 7. The new although admittedly imaginative hypothesis that a previously undescribed type of disease of the frontal sinus of unknown etiology, may be present, is presented. 8. This type of disease of the frontal sinus may be present more frequently than is reported, because of a “low‐index of suspicion” on the part of the rhinologist, because of th