Odd localisation for a gastric cancer histology

•More than 96% of signet-ring cell carcinomas occur in the stomach.•Primary SRC carcinoma of the colon and rectum is very rare.•It spreads mainly to the lymph nodes and to the peritoneum and rarely to the liver.•It presents at advanced stages and has a dismal prognosis.•Upper endoscopy is the investigation of choice to exclude a primary gastric cancer.

IntroductionMore than 96% of signet-ring cell carcinomas occur in the stomach and the rest in other organs, including the gallbladder, pancreas, urinary bladder and breast. Primary signet-ring cell carcinoma of the colon and rectum is very rare, accounting for 0.1%–2.4% of all colorectal cancers.Presentation of caseWe report a case of a 55-year old man who is operated for a caecal mass evocative of an appendicitis abscess. Intraoperatively, we discover a large, ulcerated ilio-caecal mass with several lymphadenopathies. The further workup reveals a primary signet-ring cell carcinoma of the colon with multiple lymph nodes and osteolytic bony metastases.DiscussionPrimary signet-ring cell carcinoma of the colon and rectum presents usually as an advanced stage disease with a dismal prognosis. It spreads mainly to the lymph nodes and to the peritoneum and very rarely to the liver. The mean age of patients diagnosed with primary signet-ring cell carcinoma is significantly younger than for ordinary adenocarcinoma. The upper endoscopy is the investigation of choice to exclude a primary gastric pathology. There are very few reports about this type of cancer and no reports about this type of cancer associated with osteolytic bony metastases.ConclusionThe characteristics and pathophysiology of a primary signet-ring cell carcinoma of the colon and rectum are not well understood. Usually only palliative treatment is possible. The importance of an early diagnosis of this tumor is mandatory to have a curative approach.