Tumours, abscesses, cysts, scars and fractures are familiar types of what we shall
call pathological continuant entities. The instances of such types exist always in
or on anatomical structures, which thereby become transformed into
pathological anatomical structures of corresponding types: a fractured tibia, a blistered thumb, a
carcinomatous colon. In previous work on biomedical ontologies we showed how the provision
of formal definitions for relations such as is_a, part_of and transformation_of
can facilitate the integration of such ontologies in ways which have the potential
to support new kinds of automated reasoning. We here extend this approach to the
treatment of pathologies, focusing especially on those pathological continuant entities
which arise when organs become affected by carcinomas