Origin and growth of otosclerosis

Development of head and neck pathology in Europe

This review gives a brief history of the development of head and neck pathology in Europe from a humble beginning in the 1930s to the explosive activities the last 15 years. During the decades before the introduction of immunohistochemistry in the 1980s, head and neck pathology grew as a subspeciality in many European countries. In the late 1940s, the Institute of Laryngology and Otology with its own pathology laboratory was founded in London, and in 1964 the World Health Organization (WHO) International Reference Centre for the Histological Classification of Salivary Tumours was established at the Bland-Sutton Institute of Pathology, also in London. International collaboration, and very much so in Europe, led to the publication of the first WHO Classification of Salivary Gland Tumours in 1972. In the 1960s, a salivary gland register was organised in Hamburg and in Cologne the microlaryngoscopy was invented enabling microscopic endoscopic examination and rather shortly afterwards a carbon dioxide laser attached to the microscope became established and laryngeal lesions could be treated by laser vaporisation. During the last three decades, the use of immunohistochemistry supplemented with cytogenetic and refined molecular techniques has greatly facilitated the pathological diagnostics of head and neck lesions and has had a huge impact on research. Collaboration between different European centres has drastically increased partly due to establishment of scientific societies such as the Head and Neck Working Group (HNWG) within the European Society of Pathology and the International Head and Neck Scientific Group (IHNSG). A very large number of European pathologists have contributed to the 2nd, 3rd and 4th WHO books, and are involved in the upcoming 5th edition. Accredited educational meetings and courses are nowadays regularly arranged in Europe. Numerous textbooks on head and neck pathology have been written and edited by European pathologists. The increased collaboration has created larger series of tumours for research and new entities, mainly defined by their genetic abnormalities, are continuously emerging from Europe, particularly regarding salivary gland neoplasms and "undifferentiated" sinonasal tumours. These findings have led to a better and more precise classification and open the possibilities for new treatment strategies.

Update From the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Tumours of the Ear

The 2017 fourth edition of the World Health Organization Classification of Tumours, specifically as it relates to the ear (Chap. 9), has several changes. Importantly, the number of entities has been significantly reduced by omitting tumors or lesions if they do not occur exclusively or predominantly at this site or if they are discussed in detail elsewhere in the book. These entities include: embryonal rhabdomyosarcoma, osteoma, exostosis, angiolymphoid hyperplasia with eosinophilia, Schneiderian papilloma, inverted papilloma, lipoma of the internal auditory canal, hemangioma, hematolymphoid tumors, and secondary tumors. Paraganglioma was included in the neck chapter. New entries include otosclerosis and cholesteatoma, while refinements to nomenclature, classification and criteria were incorporated into the ceruminous gland tumors and epithelial tumors of the middle and inner ear. Specifically, the middle and inner ear were combined, as practical limitations of origin and imaging make a definitive separation artificial. The classification reflects the state of current understanding for these uncommon entities, with this update only highlighting selected entities that were the most significantly changed.

[The experience with the reconstruction of the superoposterior wall of the external auditory meatus during stapedoplasty]

The objective of the present study was to improve the effectiveness of stapedoplasty by developing the method for the prevention of the formation of retraction pockets in the tympanic membrane and cicatrical fixation of auditory ossicles. A total of 60 patients presenting with grade I-II otosclerosis and conductive or mixed-type hearing impairment were surgically treated during the period from 2008 to 2014. Twenty four of these patients had undergone stapedoplasty in the preceding period in different clinics that either failed to improve their conditions or resulted in their deterioration. A new method was proposed for the reconstruction of the superoposterior wall of the auditory canal during stapedoplasty that consists of the replacement of the removed fragment by the last 150-200 mcm ultrathin allocartilaginous plate. This plate prevented the subsequent retraction of the superoposterior portions of the tympanic membrane and its fusion with either the long process of the anvil bone or the prosthetic ring. The method of this operation is described. The analysis of long-term results of the treatment confirmed the high effectiveness of the proposed approach.

Atypical mature bone in the otosclerotic otic capsule as the differentiated zone of an invasive osseous neoplasm

CONCLUSION

A large proportion of the mature otic capsule bone in cases of otosclerosis lies in plaques in direct contiguity with active otosclerosis and, because it shows significant structural defects, it should be regarded as part of the otosclerotic process. These appearances support our previously described suggestion that otosclerosis is an invasive osseous neoplasm, the mature atypical bone representing differentiation of earlier-formed invasive neoplastic osseous tissue.

OBJECTIVES

We sought structural features in differentiated bone within the otic capsules of cases of otosclerosis that might indicate a relation to the underlying disease process.

METHODS

Fifty temporal bones from 42 adult patients with otosclerosis were processed into stained histological sections and the appearance of the otic capsule was compared with that of the same tissue, processed in the same way, in 10 cases that did not show otosclerosis.

RESULTS

In the cochlear otic capsules of otosclerotic temporal bones, when traced back along the otosclerotic plaque from the invasive front, atypical shapes and arrangements of osteons were seen, often with otospongiosis (severe dilatation of multiple Volkmann's canals), culminating in larger differentiated osteons with irregularities in structure. In the medial region of the otosclerotic cochlear otic capsule, at a similar position to that where giant normal osteons are present in the normal temporal bone, differentiated, giant abnormal osteons were seen. In the otosclerotic vestibular otic capsule there were changes similar to those of the otosclerotic cochlea (apart from the giant osteons) and many osteons composed of clusters of atypical osteoblast-like cells around highly atypical Volkmann's canals.