Abstract
Leukaemic and lymphomatous infiltration of the appendix is rare and even rarer is acute appendicitis as the initial manifestation. From our routine biopsy material we collected four cases of haematological malignancies presenting as acute appendicitis or acute abdomen, caused or accompanied by tumoral infiltration of the appendix. Appendicitis was the initial manifestation that allowed diagnosis of the underlying disease. The clinical histories and histological examinations of the appendices and of one autopsy are described. We report the first detailed description of acute myeloid leukaemia involving the appendix, and three cases of lymphomatous infiltration of the appendix presenting with appendicitis, and give an overview of the literature. In these days of budgetary cuts in national health services, where one may be tempted not to have seemingly commonplace cases of appendicitis histologically verified, our cases emphasize that careful histopathological examination of all appendectomy specimens should be mandatory. Despite the fact that leukaemia and lymphoma of the appendix are rare, our cases illustrate that these must be included in the differential diagnosis of acute appendicitis and that physicians and surgeons have to be aware of these conditions.