Aims: Medullary carcinoma of the large bowel occurs mainly right-sided in elderly females. The tumour is almost invariably microsatellite instable and has been associated with favourable outcome. Our study aimed to present three cases of medullary carcinoma originating from the small bowel.
Methods and results: We describe three cases of small bowel medullary carcinoma. Two patients had coeliac disease, diagnosed at the ages of 79 and 71 years, respectively. The tumours showed the characteristic syncytial growth pattern with marked intratumoral lymphocytic inflammation. Loss of MutL homologue 1 (MLH1) [and postmeiotic segregation increased 2 (S. cerevisiae) PMS2] expression was observed in all cases, consistent with high-level microsatellite instability. All tumours were negative for Epstein-Barr virus. Follow-up information was available for one patient, who is recurrence-free 6 years after resection.
Discussion: Medullary carcinoma of the small bowel is exceedingly rare. Our data and a review of the literature suggest that this tumour type is characteristic for coeliac disease and may be the histological type underlying small bowel cancers with high-level microsatellite instability in patients with coeliac disease.
Keywords: coeliac disease; ileum; jejunum; medullary carcinoma; microsatellite instability.
© 2015 John Wiley & Sons Ltd.