[Upper maxillary cysts: embryogenic and surgical considerations in our cases]. / Cisti del mascellare superiore: considerazioni embriogenetiche e chirurgiche su una nostra casistica.

Upper maxillary cysts are a chapter in otorhinolaryngological pathology which have been relatively neglected by the Literature. The reason for this most likely lies in the difficulty in producing a nosographic picture of these pathologies which border on other surgical fields (dentistry, maxillofacial surgery), and because they show significant clinical and etiopathogenic polymorphism. The elements that characterize upper maxillary cysts as a separate clinical entity are basically their cystic nature and origin within the upper maxillary bone, although they can expand widely within the medio-facial region (nasal vestibule, oral vestibule, nasolabial region, palate, maxillary sinus). After having reviewed the various classification schemes proposed over the years, and briefly examining the main clinical and etiopathogenic characteristics and principles for surgical treatment, the present work offers a surgical case study, together with the related iconography. Moreover this work does not neglect embryogenic considerations which are indispensable for the study of some of these pathologies. In this manner the results for 35 surgical procedures on upper maxillary cysts performed from 1989 to 1996 are presented and classified following the Cudennec classification module (1991). This study shows the variety of possible clinical manifestations for these pathologies. Such a variety makes correct diagnosis imperative--today facilitated by modern imaging techniques--and requires diversifying the surgical approach, conditioned not only by the site, extension and nature of the specific lesion, but also by the related symptoms. The significant progress in surgical techniques has made increasingly functional surgery possible and led to the abandonment of such conventional radical techniques as the Caldwell-Luc procedure. Moreover, CT and NMR have provided good image definition, specifying precisely the limits and extensions and, in most cases, facilitating diagnosis of the nature of the disorder with direct and indirect signs of the cystic nature of the lesions whenever the clinical data proves inadequate.

Globulomaxillary cyst revisited.

Classically, the globulomaxillary cyst was considered to be an inclusion or developmental cyst that arises from entrapped nonodontogenic epithelium in the globulomaxillary suture. Subsequently Christ disputed the existence and histogenesis of this lesion stating that the evidence indicated that facial processes per se did not exist. The development of the anterior maxilla was attributed to the merging of growth centers rather than fusion of facial processes, and hence ectodermal entrapment was ruled out. Recent embryologic studies, however, have demonstrated that Christ's view of facial development was incorrect. Fusion of facial processes does occur, and epithelium is entrapped in areas that later will lie between the maxillary lateral incisors and canines. This review argues that embryologically and histopathologically the globulomaxillary cyst should again be considered as an identifiable clinicopathologic entity.

Intraneural and perineural epithelial structures.

The fact that numerous embryologic epithelial remnants are a normal occurrence in the oral region is well known. That some of these epithelial remnants occur within peripheral nerves is less well known. This study presents examples of intraneural epithelial rests from 3 different anatomic sites: the soft tissues of the jaws (a juxtaoral organ of Chievitz), the posterior maxilla (an ondotogenic rest), and the anterior maxilla (a nasopalatine duct remnant). The purpose of this paper is to draw the attention of surgical pathologists to this phenomenon in the head and neck in order to avoid extensive unnecessary surgery.