Mucinous epithelial cysts of the spleen associated with pseudomyxoma peritonei

Aims: We report two rare cases of neoplastic pseudomyxoma peritonei associa ted with splenic mucinous epithelial cysts and review previously reported c ases of splenic mucinous lesions in order to investigate the extent and imp lications of such an association. Methods and results: The majority of mucinous lesions of the spleen appear to be associated with pseudomyxoma peritonei. The clinicopathological profi le of these cases conforms to that of neoplastic pseudomyxoma peritonei, sh owing a similar age of onset, outcome and histological features. Most of th e cases were associated with a confirmed or suspected appendiceal primary. The immunophenotype (cytokeratin 7 negative; cytokeratin 20 and CEA positiv e) of the lesions of both our cases, including those in the ovary, was sugg estive of a gastrointestinal origin. Conclusions: Splenomegaly due to cystic intrasplenic mucinous epithelial le sions may occasionally be the presenting feature of pseudomyxoma peritonei or herald tumour recurrence. Mucinous epithelial cysts of the spleen may al so precede the development of pseudomyxoma peritonei. All cases of pseudomy xoma peritonei should be investigated for splenic involvement and, converse ly, a primary mucinous neoplasm sought elsewhere in the abdomen in all case s of splenic mucinous cysts.