Clinical and histological features of secondary carcinomas in gastrointestinal tract biopsies

Background: Secondary carcinoma involving the gastrointestinal (GI) tract is an uncommon finding in biopsy specimens. The diagnosis can be challenging for tumours mimicking a primary carcinoma and when the clinical context is unknown.

Methods and results: A multicentre retrospective study was performed to evaluate the clinical and histological features of a series of secondary carcinoma in GI biopsies. A total of 197 cases from 190 patients (median age = 67 years; 57% females) were reviewed. In 16% of patients, the primary carcinoma was unknown. Most lesions presented endoscopically as mucosal or submucosal masses (58%). In 13%, the endoscopy was non-suspicious for malignancy. The most common tumours were carcinomas of the breast (38%), kidney (13%), lung (12%), prostate (8%) and ovary (7%). The sites of involvement were the stomach (34%), colon (27%), rectum (18%), duodenum (13%), oesophagus (5%), jejunum (3%) and anus (0.5%). Histological patterns of infiltration were mucosal (76%), submucosal (41%), lymphatic (14%), and epithelial colonisation (8%). Submucosal infiltration was found significantly more frequently in carcinomas of the prostate (67%) and lung (62%), compared with carcinomas of the ovary (27%) and breast (23%). Histological obstructive changes were observed in 36% of all cases, with the highest rate in prostate carcinoma (53%) and the lowest rate in kidney carcinoma (8%).

Conclusion: Awareness of the main clinical and histological patterns of secondary carcinomas in GI tract biopsies may help pathologists to raise the possibility of this uncommon diagnosis and confirm it with the judicious use of immunohistochemistry.