Cytomegalovirus induced pseudotumor of the colon in a renal transplanted patient

Cytomegalovirus induced pseudotumor of the colon in a renal transplanted patient


Introduction
As common viral pathogens affecting the digestive tract, the clinical and radiographic findings of CMV related infections, namely esophagitis, gastritis, enteritis, and colitis have been well documented in immunocompromised patients (1,2).

Case Presentation
A 42-year-old male, diagnosed as end-stage renal disease (ESRD) in 2005 and on renal replacement therapy since the past 4 years, underwent renal transplant in 2009.He was on standard triple drug immunosuppressive medications (prednisolone, azathioprine, cyclosporine).Initially he remained asymptomatic for 2 year after the kidney transplantation but later on was admitted with complaints of loose stools, which occurred more than 5 times per day, were watery in consistency, associated with tenesmus and containing fresh red colored blood.Significant weight loss of around four kilograms in 5 months was also noted.His general physical examination was unremarkable except for blood stained finger on digital rectal examination.On abdominal examination, there was mild tenderness in epigastric region.Gut sounds were audible.Pulmonary, cardiovascular and neurological examination was unremarkable.Lower gastrointestinal endoscopy revealed multiple polyps in distal sigmoid and proximal rectum (Figure 1), showing bleed to touch mucosa.Multiple biopsies were taken and the histological examination of these biopsies revealed granulation tissue formation and mixed inflammatory cell infiltrate.Occasional endothelial cells show enlarged nuclei with inter-nuclear inclusions compatible with CMV (Figure 2).His treatment consisted of intravenous ganciclovir for 5 weeks.Endoscopy was repeated after 6 weeks, which revealed a persistent mass in his distal sigmoid along with slight decrease in its size.Repeated biopsies tested negative for CMV.During the course of illness, he was found to have hepatosplenomegaly and ascites.His HCV RNA became detectable, which was negative at the time of renal transplant in 2009 .He later on developed abdominal distention due to ascites.On further investigations, patient was diagnosed as decompensated chronic liver disease secondary to Hepatitis C virus with a Child-Turcotte-Pugh score (CTP class B9).The patient had a protracted course and his paralytic ileus did not settle and he died because of sepsis.

Discussion
CMV infection of the digestive tract is of often seen in immuno-compromised patients, who either have a history of HIV infection or are on immunosuppressive drugs, consisting post-transplant patients.It can infect any part of the gastrointestinal tract from the esophagus to the rectum, either diffusely or in an isolated form and can cause colitis, esophagitis, and gastritis (3).In our patient lesions were found in sigmoid colon, causing colitis.Pathogenesis of such CMV induced pseudotumor remain unknown.Bowel wall thickening that is seen in patients having CMV infection is histologically due to submucosal edema, granulation tissue along with fibrosis.The histological characteristics of a pseudotumor are inflammatory infiltration in the mucosa and submucosa layers, inclusion bodies mostly in endothelial cells along with extensive fibrosis, granulation tissue, and chronic inflammation (4).Histological examination of our patient revealed the same findings.All these changes may cause a gastrointestinal inflammatory mass that might cause obstruction of the bowel, mimicking an exophytic neoplastic luminal mass lesions on barium studies (5).In our case, no such obstruction was seen however bleeding from rectum was noted, which is a rarity with these type of lesions.For gastrointestinal mass lesions in the transplant population, CMV induced pseudotumor should be included in the list of possible differential diagnosis (6).These tumors often responds to antiviral therapy.In our case with the treatment of the patient, the CMV infection did resolve, however the pseudotumor persisted.Surgery's role as a treatment option for CMV-induced mass is still not clear and the role of immune reconstitution in this group of patients is still under investigation (7,8).Larger studies are needed to further enhance our knowledge about this entity and to outline treatment guidelines.

Conclusion
Gastrointestinal mass lesions in transplanted individuals should include CMV induced pseudotumor in the list of possible differential diagnosis.
Authors' contribution SML and NHL; managed the patient.ZM and RM; wrote

Figure 1 .
Figure 1.Endoscopic images showing multiple polyps in the sigmoid colon.
the report.MM; responsible for histological diagnosis and images.