Cytomegalovirus colitis masquerading as rectal malignancy in an immunocompetent patient.

Gastrointestinal tract (GIT) involvement by cytomegalovirus (CMV) infection is well-recognized in immunosuppressed patients but is uncommon in immunocompetent hosts. The colon and esophagus are the most frequently affected sites with punched out ulcers being the characteristic mucosal lesion. CMV-induced pseudotumor is an exceptionally rare presentation, especially in immunocompetent hosts. A 76-year-old immunocompetent female presented with abdominal pain and constipation. Colonoscopy revealed an ulcerated polypoidal tumor-like mass in the anorectal region. Biopsy of the lesion showed large basophilic intranuclear inclusions which were positive for CMV on immunohistochemical staining. The patient responded to 2 weeks of antiviral therapy with complete resolution of the mass. Although rare, pseudotumors associated with CMV infection should be considered in the differential diagnosis of tumorous lesions of the GIT.

Benign signet ring cells in pseudomembranous colitis: A diagnostic trap.

A 71-year-old female patient was admitted with intractable diarrhea and abdominal distention following several courses of broad spectrum antibiotic therapy. Colonic biopsy revealed pseudomembranous colitis with foci of signet ring cell (SRC) change. The SRCs possessed bland nuclei and were confi ned to the basement membranes of the crypts with no infi ltration into the lamina propria. Benign SRCs in pseudomembranous colitis is an uncommon phenomenon. Awareness of this rare, but potential pitfall is of utmost importance to avoid a misdiagnosis of SRC carcinoma.