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The list of tumours which may be defined uncommon (i.e., those tumours whose incidence is (2/100.000) is by no means minuscular. Their low frequency and the ensuing difficulty in collecting at a single Centre a number of cases sufficient to become experienced with their management, make their clinical and histopathologic identification as well as their prognostic evaluation and treatment a difficult task. Unlike what happens with common tumours, the clinical and basic research studies on uncommon tumours are scarce, and the institutions which can undertake their diagnosis and treatment very few. Furthermore, for the diagnosis of uncommon tumours is often necessary to resort to sophisticated machinery or laboratory techniques not widely available or affordable. Another limiting factor is given by the lack of financial support, which is mainly conveyed on studies on those tumours that, because of their high frequency, have a stronger social impact.A means to circumvent these drawbacks is offered by the World Health Organization Collaborating Centres. These are national institutions designated by the UN sanitary arm as reference centres for the study of medical-social problems, including cancer. By definition, a WHO Collaborating Centre forms part of an inter-institutional collaborative network set up by W.H.O. at the national and international levels, thus contributing to the local and global development of specific health resources. |
