巨細胞病毒（CMV)感染常發生在嚴重免疫能力缺損的病人。那些後天免疫不全症候群、移植手術後接受免疫抑制治療或惡性腫瘤接受化學治療和長期使用類固醇的病人，皆爲高危險群。巨細胞病毒感染可能存在於病人的胃腸道内，但祇有少數病人會發生臨床上明顯的症狀。感染巨細皰病毒最重要的診斷標準在於排除其它的感染病原如黴菌、其它病毒、寄生蟲和細菌感染後，並在被感染細胞中可發現病毒的包涵體（inclusionbody)。我們在此報導了一偃72歲的女性多發性骨髓瘤病人，因大量血便，而接受大腸内視鏡檢查，内視鏡發現因爲嚴重大腸發炎而導致彌漫性潰瘍和罕見的偽息肉病灶。従大腸病灶部位取得切片檢體，並以hematoxylin&eosionstain染色和針對巨細胞病毒單株抗體（anti-CMVmonoclonal antibody)特別免疫組熾化學染色，可以發現巨細胞病毒的包涵體。雖立即於診斷後以ganciclovir 治療，但病患臨床症狀仍持續惡化而死亡。

Cytomegalovirus ( CMV ) infection can occur in severely immunocompromised populations, such as people suffering from acquired immunodeficiency syndrome ( AIDS ), patients receiving immunosuppressive therapy after transplantation or undergoing chemotherapy for malignanies, and long-term corticosteroid users. CMV frequently occurs in the gastrointestinal tract of such immunocompromised individuals, but only a few of them develop clinically apparent CMV disease. The gold standard of diagnosis for CMV infection is the presence of viral inclusion bodies in infected cells, after the exclusion of other viral, fungal, parasitic, and bacterial infections. CMV colitis results in lesions varying from segmental to extensive mucosal ulcerations. We report a rare endoscopic feature of severe and extensive colitis, resembling pseudo-polyp lesions, observed in a 72-year-old woman with myelomatosis who had suffered from progressive bloody diarrhea and abdominal pain for one month. Histological examination of biopsies from the ulcer bases, stained with hematoxylin and eosin ( H&E ) and an immunohisto-chemical stain for anti-CMV monoclonal antibody confirmed the presence of CMV inclusion bodies. The patient expired despite treatment with ganciclovir.