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CMV Colitis Masquerading As Colon Cancer - An Unusual
Presentation Of Acquired Immunodeficiency Syndrome
P K H Chow, J M S Ho, A E Ling, H S Goh
We present a case-report of a patient with a typical history and a
barium enema study diagnostic of right-sided colonic cancer. Laparotomy
and right hemicolectomy was carried out. Histological examination revealed
Cytomegalovirus (CMV) colitis and the patient was subsequently tested positive
for Human Immunodeficiency Virus (HIV).
Gastrointestinal symptoms are common in patients with Acquired Immune
Deficiency Syndrome (AIDS) and up to 10% of all AIDS patients have CMV
colitis. The diagnostic criteria for CMV colitis is reviewed. AIDS is likely
to become more common and we stress the awareness of this condition as
well as the need for preoperative colonoscopy and histological diagnosis
in patients with radiological diagnosis of colorectal carcinoma.
Keywords: CMV colitis, AIDS, colorectal cancer, colonoscopy
Cytomegalovirus (CMV) is an ubiquitous beta herpesvirus which usually
causes subclinical infections in children and young adults. The virus is
then carried for life but remains latent. When there is compromise of T-lymphocyte
mediated immunity as seen in organ transplantation, lymphoid neoplasia
and Acquired Immunodeficiency Syndrome (AIDS),CMV reactivation syndromes
can develop. These manifest as retinitis, gastroenteritis or fulminant
disseminated disease. In HIV infection, CMV reactivation syndromes usually
appear late at the advanced stage of the disease.
While CMV infection is common in the general population, gastrointestinal
CMV involvement is, with few exceptions, found almost exclusively in compromised
hosts and may involve any part of the gut from oesophagus to rectum(1).
The colon is the most common site of involvement and as many as 10% of
AIDS patients have CMV colitis(2,3).
Such patients present with severe, intractable diarrhoea, weight loss,
fever, and rectal bleeding or melaena or with complications of the colitis
such as bleeding or perforation(4).
We present a case-report of CMV colitis masquerading as caecal cancer
which led to the diagnosis of AIDS.
A 46-year-old hawker presented with a one- month history of abdominal
discomfort and change of bowel habits in the form of intermittent constipation
and watery diarrhoea. There was occasional fresh bleeding per rectum. He
also complained of loss of weight of about 10 kg over the same period of
time. Clinical examination was normal and a barium enema showed a constant
narrowing in the caecum suggestive of cancer (Fig
The patient had a laparotomy and right hemicolectomy was performed.
On cutting open the specimen, the caecum and ascending colon showed multiple
tiny ulcers each about 0.2 to 0.3 cm in diameter. There was no evidence
of perforation of the ulcers and the intervening mucosa was markedly oedematous,
resulting in an overall narrowing of the lumen. The ileocaecal valve was
also congested with tiny ulcers measuring 0.2 cm in diameter. There was
no evidence of diverticular disease. The patient made an uneventful post-operative
recovery and was discharged five days after his surgery.
Histological examination of the resected specimen showed that the ulcers
were superficial, involving mucosa and submucosa only (Fig
2). Scattered amidst the inflammatory cellular infiltrate at the ulcer
bases and the lining blood vessels were cells with enlarged nuclei containing
prominent basophilic inclusions (Fig
3 and 4).
Immunoperoxidase stains for cytomegalovirus showed marked positivity
in these cells, confirming the presence of cytomegalovirus infection. The
mucosa adjacent to the areas of ulceration showed granular atrophy suggesting
ischaemic changes. There was no evidence of malignancy in the specimen.
The patient readmitted himself a few weeks later for bleeding and painful
piles for which haemorrhoidectomy was carried out. He was found to have
proctitis with oedematous rectal mucosa and contact bleeding.
HIV infection was suspected when CMV colitis was diagnosed. On closer
questioning, the patient gave a history of multiple unprotected sexual
exposure with prostitutes. At both admissions, clinical examination was
normal with no evidence of adenopathy nor hepatosplenomegaly. Chest X-ray
The patient was subjected to full haematological and serological examination.
These showed a leucocyte count of 3.38 x 109/L with a differential count
of 47% polymorphonuclear cells, 34% lymphocytes and 12% monocytes. Haemoglobin
was 9.8g/dL and platelet count was 190 x 109/L. Peripheral blood film was
normal. Liver function tests were normal with no increase in the levels
of serum aminotransferases. CMV antibody level using complement fixation
methods was 64.
Circulating lymphocyte subpopulation counts showed TCD4 at 13.4% (26.6
- 37.0) and TCD8 at 55.0% (16.3 - 27.1), with absolute counts of TCD4 at
129 cells/UL (342 - 929) and TCD8 at 529 cells/UL (103 - 717). CD4/CD8
ratio was 0.2 (1.0 - 2.2). The patient's HIV status was determined by a
positive enzyme immunoassay (EIA) for HIV antibodies (Abbot, 3rd generation
EIA), and confirmed by Western Blot (Genelabs Diagnostic, Singapore).
The patient has been informed of his HIV status and has been referred
to the Communicable Disease Centre for counselling and further management.
Cytomegalovirus colitis is one of the most common and potentially serious
opportunistic pathogens of the gastrointestinal tract in AIDS patients.
It reportedly affects up to 10% of all AIDS patients(2,3).
Virtually all organs of the alimentary tract are susceptible to CMV disease.
The most common manifestation of enteric cytomegalovirus disease is colitis
and this usually presents with severe, intractable diarrhoea, weight loss,
fever, and rectal bleeding or melaena(4).
The presentation is therefore non-specific and common to many other gastrointestinal
The underlying pathology is believed to be a CMV-induced endothelial
vasculitis that results in ischaemia and possibly transmural infarction.
Patients with CMV colitis may also present with complications of the colitis,
namely bleeding, perforation and necrotising colitis requiring emergency
laprotomy and resection. The prognosis in this case becomes grave.
Diagnosis is by endoscopy which shows submucosal haemorrhage and diffuse
Endoscopic findings are however non-pathognomonic and gross lesions ranging
from erythematous patches to deep and wide coalescing ulcers may be found.
The absence of endoscopic ulcerative lesions however has a 98% negative
Multiple endoscopic biopsies should be carried out as the disease is multifocal
and the biopsy specimen should be sent for viral culture of CMV, antigen
assay and histopathology for intranuclear CMV inclusions. Biopsies from
the caecum are more likely to be diagnostic(7).
Most authorities diagnose CMV associated gastrointestinal disease when
the biopsy specimen shows cytomegalic inclusion cells with surrounding
Barium enema is non-definitive as CMV colitis mimicks other forms of
barium enema may be normal. CMV colitis simulating carcinoma has not been
previously reported in the literature.
When diagnosed, management of CMV colitis is primarily medical. Intravenous
Ganciclovir (dihydroxypropoxymethyl guanine)(8)
or Foscarnet (sodium phosphonoformate) are used with good response rates
but are not without side-effects(9).
The clinical efficacy of intravenous Ganciclovir and Foscarnet for the
treatment of CMV colitis is fairly similar. Most trials reported 57% to
75% improvement rate with either drug. These drugs could lead to the elimination
of ulcerative lesions, CMV intranuclear lesions and CMV culture from the
these drugs have shown a reasonable improvement rate for treatment, its
role as life-long suppressive agents for colitis is uncertain(10).
Surgery is indicated for complications of the disease. Mortality is
high when complications such as perforation or necrotising colitis occur
as these patients are immunocompromised. Post-operative mortality of 28%
at day one and 71% by one month has been reported(11).
In this patient, preoperative colonoscopy could have diagnosed the
CMV colitis. With increasing incidence of HIV infection and CMV colitis,
there is a greater need for colonoscopic examination even in cases with
typical history and barium enema diagnostic of right-sided cancer.
The incidence of AIDS patients is expected to increase and many of
them will present with gastrointestinal symptoms(12).
It will become increasingly important for surgeons and other health-care
workers to be aware of the gastrointestinal manifestations of AIDS. A high
index of suspicion is required for early diagnosis in order that appropriate
early treatment may be instituted before complications develop.