Abstract
Abstract
Salivary duct carcinoma (SDC) is characterised as an infrequent highly aggressive malignant tumour of the salivary gland, often diagnosed at an advanced stage. Due to the low incidence of SDC, only limited data about this neoplasm are available. There are conflicts regarding to the prevalence, staging, prognosis, treatment and clinical behaviour of this tumour. Some studies have suggested a possibility that some immunohistochemical characteristics are related to a better prognosis than earlier described. In addition to this hypothesis, morphologic mimicry among human malignant neoplasms is a well-known phenomenon in surgical pathology. This is the origin of a hypothesis of similarities between SDC and ductal carcinomas in the breast and in the prostate. The aim of the present study was to substantiate these hypotheses. Twenty cases were included during the period 1999 to 2004 and observed until 2007. A review of all the similar cases published in the literature and comparison with the present series was performed. The study represented a counterweight to the low prevalence described in the literature. Surgery was the treatment of choice, combined with individualized radiotherapy. Most tumours seemed to make its first appearance at a lower histological stage than had at first been thought. This correlated with the hypothesis of a classification of SDC into a low- and high-grade carcinoma, with the first mentioned associated with a better prognosis. Review of the literature indicated that androgen receptor is expressed in more than 90 % of SDCs, and some studies have indicated a possibility that this receptor is of special prognostic interest. Immunohistochemical investigations have also confirmed hormonal concordance between SDC and ductal carcinomas in the breast and in the prostate raising the question of whether similar treatment strategies can be used. This should be further investigated.