We present a case of peritoneal mesothelioma that
presented with fever of unknown origin and an elevation
in the inflammatory parameters. Radiological imaging
did not reveal a diagnosis. Because of tumour-associated
inflammatory activity, indium-111 leucocyte scintigraphy
enabled us to establish a diagnosis. To our knowledge,
the use of indium-111 leucocyte scintigraphy in peritoneal mesothelioma has not been reported previously.