An immunohistochemical study of adenoid cystic carcinoma of the external auditory canal

Ceruminous Adenoma: A Rare Mass that Impair Hearing

Ceruminous adenoma is described as a glandular neoplasm of ceruminous glands. It is seen for less than one percent of all external ear tumours. Ceruminous adenoma cases were reported to have recurrence and residual tumour, however there was no malignant transformation known in ceruminous adenoma up to this date. Here, we report a young adult woman with two years history of progressive reduced hearing and tinnitus of the right ear. She was proven to have right moderate conductive hearing loss with pure tone audiometry. There was a cystic mass with serous content arising from the posterior wall of the right ear canal. We proceeded with wide local excision of the mass via trans-canal approach. Ceruminous adenoma was confirmed with histopathology and immunohistochemistry of CK7 staining. The hearing impairment was resolved completely post excision and there was no recurrence of the tumour on one year follow-up. We concluded wide local excision with appropriate margin of the mass is adequate to prevent recurrence in ceruminous adenoma cases.

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.

Adenoid cystic carcinoma of the skull base

Adenoid cystic carcinoma (ACC) is a slowly growing tumor with a particular tendency to infiltrate the surrounding tissue by perineural spread. The clinical diagnosis may prove difficult due to the submucons extension of the tumor, especially at the skull base. This article outlines the clinical characteristics, diagnostics, and treatment modalities in a series of 56 patients with an ACC in the head and neck diagnosed between 1970 and 1998 in 32 females and 24 males. The youngest patient was aged 24 years, the oldest 77 years. The average age was 54 years. In 16 patients the tumor originated in the paranasal sinuses or the nasopharynx and involved the skull base. As a rule, several months passed between the manifestation of the first symptoms such as pain, blocked nose, epistaxis, or diplopia and the initial clinical diagnosis. All patients received surgical treatment, however, complete microscopical resection could only be achieved in approximately one third of the cases. Therefore, nine patients were postoperatively treated with radiotherapy. The average survival rates of the patients with an ACC of the skull base were only 99 months as compared to 144 months in the patients without skull base involvement.

Human ceruminous gland: Ultrastructure and histochemical analysis of antimicrobial and cytoskeletal components

The ceruminous glands in the skin of the human external auditory canal are modified apocrine glands, which, together with sebaceous glands, produce the cerumen, the ear wax. Cerumen plays an important role in the protection of the ear canal against physical damage and microbial invasion. We studied the morphology of the glandular cells by light and electronmicroscopy. Antimicrobial and cytoskeletal components of the ceruminous glands were investigated by immunohistochemical methods. Numerous antimicrobial proteins and peptides are present in the ceruminous glandular cells: beta-defensin-1, beta-defensin-2, cathelicidin, lysozyme, lactoferrin, MUC1, secretory component of IgA. These data indicate a crucial role in the innate host defense against diverse pathogens. The apocrine secretion mechanism is a special mode of secretion by which the apical part of the cell cytoplasm surrounded by a membrane is pinched off. We could show that the presence of actin filaments, CK 19 and CK 7, seems to play a role in the pinching-off mechanism. Finally, we showed the secretion of lipid vesicles from the ceruminous gland. We could extend the number of detected antimicrobial peptides and proteins in human ceruminous glandular cells that protect the surface of the external auditory meatus. In addition, we detected proteins involved in the apocrine secretion mode of the ceruminous gland.

Dendritic cells in the bursal follicles and germinal centers of the chicken's caecal tonsil express vimentin but not desmin

BACKGROUND

Immunohistochemical studies with anti-vimentin and anti-desmin monoclonal antibodies were designed to determine the origin of bursal secretory dendritic cells (SDC) and follicular dendritic cells.

METHODS

The binding sites of anti-vimentin, anti-desmin, and anti-chicken-IgG specific monoclonal antibodies were visualized with a biotinylated anti-mouse-IgG, ABC Elite kit, and 4-chloronaphthol. Cells were double stained (anti-vimentin and rabbit anti-chicken-IgG Fc) to determine if the vimentin positive cells possessed surface IgG.

RESULTS

Vimentin positive cells were observed in the cortex and medulla of the bursa and germinal center and lymphoepithelial compartment of the caecal tonsil. The mesenchymal reticular cell, the basic supporting cell of the germinal center, was stained prominently by anti-vimentin and anti-desmin. Both antibodies stained the bursal cortex but only anti-vimentin bound the bursal secretory dendritic cell of the medulla. In addition to being vimentin positive and desmin negative, the bursal secretory dendritic cell possessed and the follicular dendritic cell appeared to possess IgG on their surfaces. In all the observations, B-cells were vimentin negative.

CONCLUSION

These studies suggest that follicular dendritic cells and mesenchymal reticular cells in the caecal tonsil's germinal centers may be functionally different cell populations while the bursal secretory dendritic cell and follicular dendritic cell of the caecal tonsil may have a common origin.