Mucinous epithelial cysts of the spleen associated with pseudomyxoma peritonei

AIMS: We report two rare cases of neoplastic pseudomyxoma peritonei associated with splenic mucinous epithelial cysts and review previously reported cases of splenic mucinous lesions in order to investigate the extent and implications of such an association. METHODS AND RESULTS: The majority of mucinous lesions of the spleen appear to be associated with pseudomyxoma peritonei. The clinicopathological profile of these cases conforms to that of neoplastic pseudomyxoma peritonei, showing a similar age of onset, outcome and histological features. Most of the cases were associated with a confirmed or suspected appendiceal primary. The immunophenotype (cytokeratin 7 negative; cytokeratin 20 and CEA positive) of the lesions of both our cases, including those in the ovary, was suggestive of a gastrointestinal origin. CONCLUSIONS: Splenomegaly due to cystic intrasplenic mucinous epithelial lesions may occasionally be the presenting feature of pseudomyxoma peritonei or herald tumour recurrence. Mucinous epithelial cysts of the spleen may also precede the development of pseudomyxoma peritonei. All cases of pseudomyxoma peritonei should be investigated for splenic involvement and, conversely, a primary mucinous neoplasm sought elsewhere in the abdomen in all cases of splenic mucinous cysts.