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.

Origin and growth of otosclerosis.

Conclusion: The external layer of the otic capsule arises from periosteal osteoblasts, which produce large numbers of Volkmann's canals as well as lamellar bone. The main plaque of otosclerosis is a histologic replica of the external layer and seems to arise from similar cells in the periosteum and to follow a defined invasive course into the footplate of the stapes, the basal coil of the cochlea and the saccule.

Objectives: To determine by histologic study of the developing otic capsule and temporal bones with otosclerosis the site, tissue of origin, and pathways of growth of the disease.

The intravestibular source of the vestibular aqueduct. III: Osseous pathology of Ménière's disease, clarified by a developmental study of the intraskeletal channels of the otic capsule.

Conclusion: Review of the histopathological changes in the vestibular arch in Ménière's disease, after a study of development of the otic capsule, indicated a severe apoptotic loss of osteoblasts with consequent denudation of these cells from and damage to the osseous canal structure of the arch.

Objective: To review previously reported histological findings in the inner layer of the vestibular aqueduct and its intravestibular source in Ménière's disease, using newer knowledge of otic capsule development.

Methods: Temporal bone histological sections from the vestibular arch region of eight patients with Ménière's disease were reviewed in our London-based material.

The intravestibular source of the vestibular aqueduct. II: its structure and function clarified by a developmental study of the intra-skeletal channels of the otic capsule.

Conclusion: A developmental histologic study of the otic capsule indicates that it grows a system of lamellar bone with abundant interconnecting intraosseous channels. These include the 'cartilage canals' in the cartilage model, the chondro-osseous and Haversian-like (Volkmann's) canals in the ossified otic capsule, the fissula ante fenestram, which seems to function as a lifelong manufacturer of the latter two channels, and the inner layer (vestibular arch) of the vestibular aqueduct, which is a complex series of Volkmann's canals and microcanals. Chemical changes, possibly produced by breakdown of cells within the channels, may provide a homeostatic environment for the functions of hearing and balance that take place in the endolymphatic fluid.

Current review on squamous intraepithelial lesions of the larynx.

Squamous intraepithelial lesions (SILs) of the larynx, clinically usually defined as leukoplakia and chronic laryngitis, have remained the main controversial topic in laryngeal pathology for decades as regards classification, histological diagnosis and treatment. SILs are caused by smoking and alcohol abuse. There is also mounting evidence that gastroesophageal reflux is a potential aetiological factor.

Aggressive papillary tumor of the middle ear: a true entity or an endolymphatic sac neoplasm?

Aggressive papillary tumors of the middle ear are rare, and their true origin is not clear. We describe the clinical, radiologic, genetic, and histopathologic features of a papillary epithelial tumor filling the middle ear of a 68-year-old woman. Imaging revealed no evidence of petrous temporal bone apex involvement, nor did genetic studies demonstrate the von Hippel-Lindau mutation.

Origin of endolymphatic sac tumor.

Autopsy temporal bone sections showing a one mm papillary glandular neoplasm, confined to the left endolymphatic duct, are described. This is the second literature report confirming the post-mortem site of origin of the "endolymphatic sac tumor". The patient died after surgery for right vestibular schwannoma, but no features of von Hippel Lindau disease or neurofibromatosis 2 had been displayed clinically or at autopsy.

Recent technological developments: in situ histopathological interrogation of surgical tissues and resection margins.

Objectives: The tumour margin is an important surgical concept significantly affecting patient morbidity and mortality. We aimed in this prospective study to apply the microendoscope on tissue margins from patients undergoing surgery for oral cancer in vivo and ex vivo and compare it to the gold standard "paraffin wax", inter-observer agreement was measured; also to present the surgical pathologist with a practical guide to the every day use of the microendoscope both in the clinical and surgical fields.

Materials And Methods: Forty patients undergoing resection of oral squamous cell carcinoma were recruited.

Immunohistochemical characterization of the epidermoid formation in the middle ear.

Objective: To study the incidence, size, and origin of epidermoid formations after accurately characterizing them by cytokeratin immunohistochemical analysis.

Study Design: A strategy of screening sections for possible epidermoid formations in the entire eardrum area in paraffin-embedded, serially sectioned developing temporal bones was used. Unstained adjacent sections were subjected to immunohistochemical staining, to provide accurately identified epidermoid formations for a study of their appearance and size in relation to age.