Dedifferentiation in salivary gland carcinomas

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.

Carcinoma ex pleomorphic adenoma with special reference to the prognostic significance of histological progression: a clinicopathological investigation of 41 cases

AIMS

To investigate a large series of cases of carcinoma ex pleomorphic adenoma (CEPA) to determine prognostic factors.

METHODS AND RESULTS

Thirty cases of CEPA associated with primary pleomorphic adenoma (PA) and 11 cases of CEPA associated with recurrent PA were investigated. The median follow-up was 57.7 months, and ranged from 4 to 156 months. Purely intraductal carcinoma was found in 15 cases. Intraductal and extraductal intracapsular carcinoma together was found in one case. Extracapsular carcinoma was found in 25 cases. Prognosis was good for CEPA that was purely intraductal, extraductal intracapsular, or up to 5 mm extracapsular, and poor for CEPA that was 8 mm or more extracapsular. There were relatively more cases of CEPA with extracapsular invasion of 8 mm or more from recurrent PA than from primary PA, and the prognosis for CEPA associated with recurrent PA was worse than that for CEPA associated with primary PA.

CONCLUSIONS

The threshold for distinguishing minor extracapsular invasion with good prognosis from wide extracapsular invasion with poor prognosis is 5 mm. The worse prognosis for CEPA associated with recurrent PA indicates the necessity for close surveillance of patients with recurrent PA.

Malignant transformation of sialadenoma papilliferum of the palate: a case report

We report a case of a 79-year-old woman with an unusual salivary gland tumor that developed at the junction between the soft and hard palates. The tumor consisted of sialadenoma papilliferum (SP) with areas of an epithelial-myoepithelial carcinoma (EMC) component and a high-grade carcinoma component. There were also transitional regions among the SP, the EMC and the high-grade carcinoma components. The high-grade carcinoma component, which was similar to invasive micropapillary carcinoma of the breast, infiltrated into the right parapharyngeal space and metastasized to the lungs and cervical vertebrae. The high-grade carcinoma cells were positively immunostained for p53 protein. SP has been considered to be a benign tumor with exceptionally good prognosis, and, to the best of our knowledge, there has never been a confirmed case of malignant SP. This is the first report of SP with a definite malignant component.