Signet Ring Carcinoma of the Appendix Presenting as Crohn's Disease in a Young Male.

Primary signet ring cell carcinoma is a rare event in surgery. It looks like acute appendicitis and it is difficult to diagnose it on clinical grounds alone. The diagnosis is always confirmed by histopathology of a surgically removed appendix. A young man, 22 years old, presented with vomiting, diarrhea, and cramps in his abdomen without abdominal tenderness (mild abdominal discomfort in the right lower abdominal quadrant without signs of peritoneal irritation) during the previous month. The first endoscopic results showed only changes of mucosa that could be attributed to endoscopic and clinical representation of Crohn's disease. A few days after the initiation of the therapy with aminosalicylates and corticosteroids, the patient went into ileus and was transferred to the Department of Surgery, where he underwent an emergency right-sided hemicolectomy with resection of the transversal colon and forming of an ileostoma. The first pathohistological diagnosis was pseudomembranous colitis. Because the patient's condition was deteriorating, a revision of the pathohistological diagnosis was done. After careful revision and extensive sampling, a signet ring cell carcinoma arising in the appendix with infiltration of the ileocecal region was found. Immunohistochemically, tumor cells were positive for CDX-2 CK7, CK20, CK19, and carcinoembryonic antigen and negative for chromogranin A. Sixteen isolated lymph nodes were negative. Although the patient had a disease that was localized to the appendix and ileocecal region with no apparent distal metastasis, his clinical condition was worsening rapidly and he died after 2 months. This case shows the aggressive biological behavior of the appendix signet ring cell carcinoma. Scrupulous histopathological examination of the appendix is an obligatory procedure. Elimination of the signet ring cell carcinoma from other carcinoma subtypes is of special importance as it has an exceptionally poor prognosis and is generally diagnosed in its advanced stages.