International Journal of Surgery Case Reports 1 (2010) 9–11
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International Journal of Surgery Case Reports
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Actinomycosis of the colon with invasion of the abdominal wall: An uncommon
presentation of a colonic tumour
M.E.C. McFarlane∗, K.C.M. Coard
Department of Surgery, Radiology, Anaesthetics and Intensive Care, Department of Pathology, University of the West Indies, Mona, Jamaica
a r t i c l e i n f o
Received 27 July 2010
Accepted 29 July 2010
Available online 26 August 2010
a b s t r a c t
Actinomycosis is an uncommon chronic suppurative infectious disease that is caused by Actinomycetes
including cervico-facial, thoracic and abdominal actinomycosis.
Herein, we present the case of a 79-year-old male patient who underwent surgical exploration follow-
ing presentation with abdominal pain and an abdominal mass, initially thought to be a malignancy.
Pathologic examination confirmed this as a case of abdominal actinomycosis. This diagnosis should
always be included in the differential diagnosis of patients who present with an infiltrative abdominal
© 2010 Surgical Associates Ltd. Published by Elsevier Ltd.
Abdominal actinomycosis is an uncommon chronic suppura-
and anaerobic bacteria, Actinomyces israellii. The disease is charac-
terised by an infiltrative and granulomatous inflammation, which
may result in multiple abscesses, and sinuses that drain sulphur
granules. The organism is a common commensal of the oral cav-
ity and has low virulence, causing disease only when the mucosal
barrier has been breached.1
Because the clinical presentation is so variable, the disease
frequently mimics other chronic inflammatory intra-abdominal
conditions or even malignancy. In fact, an accurate diagnosis is
not often established pre-operatively in a significant number of
We report a case of actinomycosis presenting as an inflamma-
tory abdominal mass of the transverse colon with involvement of
the abdominal wall.
2. Case report
sented with a 3-week history of central abdominal pain associated
with the presence of a supraumbilical mass. There was no history
of constitutional symptoms or of a change in bowel habit. General
∗Corresponding author at: P.O. Box 110, Mona, Kingston 7, Jamaica.
Tel.: +876 926 8587; fax: +876 960 7608.
E-mail address: email@example.com (M.E.C. McFarlane).
physical examination revealed that he was afebrile with normal
vital signs. Abdominal examination revealed a hard, 6cm diame-
ter, supraumbilical mass that was moderately tender and appeared
to involve the abdominal wall. Digital rectal examination was nor-
a mass involving the anterior abdominal wall. An abdominal ultra-
sound also identified the abdominal mass indicating involvement
of the omentum. Differential diagnoses of incarcerated supra-
umbilical hernia or of an intra-abdominal malignancy, infiltrating
the abdominal wall were considered. A colonoscopy was consid-
ered to assist with making the diagnosis but was not performed
since the presence of abdominal tenderness may have indicated a
perforated colonic malignancy with a pericolic inflammatory mass.
diameter hard mass involving the transverse colon and omentum.
The mass was attached to the anterior abdominal wall and was
associated with significant fibrosis. A clinical diagnosis of carci-
noma of the transverse colon was now made and en bloc resection
of the mass, including the transverse colon and abdominal wall,
was performed with primary colonic anastomosis.
Gross pathologic examination of the excised colon revealed
a large tumour-like lesion within the bowel wall, beneath the
mucosa, which extended to the pericolic tissues. Histologic exami-
many microabscesses containing typical actinomycosis organisms
(Fig. 1). The abscesses extended through the markedly thickened
bowel wall and into the pericolic adipose tissues. The bowel, away
from the mass lesion, revealed features of diverticular disease.
There was no evidence of malignancy.
2210-2612 © 2010 Surgical Associates Ltd. Published by Elsevier Ltd.
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Open access under CC BY-NC-ND license.
M.E.C. McFarlane, K.C.M. Coard / International Journal of Surgery Case Reports 1 (2010) 9–11
Fig. 1. Histologic section of bowel wall showing characteristic sulphur granules of
an actinomycosis colony within a microabscess (H&E).
Following confirmation of the diagnosis of actinomycosis, the
patient was treated with high doses of intravenous penicillin for
a 2-week period and recovered without significant complications.
He was discharged on amoxycillin and has remained well.
Actinomycosis is an uncommon chronic suppurative infectious
disease caused by gram-positive microaerophilic and anaerobic,1
Actinomyces bacteria. It forms characteristic colonies that are
recognizable by the presence of sulphur granules. The organism
was originally classified as a fungus because of its filamentous
appearance and indolent growth that mimicked mycotic disease.
However, the absence of a nuclear membrane or chitin in the cell
membrane and reproduction by fission are among the characteris-
tics that led to its reclassification as a bacterium and not a fungus.4
The Actinomyces bacteria that cause disease belong to a strain
that can be divided into 6 sub-groups of which israelii is the most
common variety.1This organism is a normal inhabitant of the oral
cavity but, despite its relatively frequent occurrence, Actinomyces
tion when it enters the tissue following a breach in the mucosal
When infection occurs, three main clinical syndromes are
described namely: cervicofacial, abdomino-pelvic and thoracic.
The cervicofacial type is the most common presentation and
accounts for 55% of patients followed by the abdomino-pelvic
presentation in 20% and the thoracic in 15%.5,6The cervicofa-
cial variety occasionally follows dental extractions; the thoracic
type is associated with pulmonary infections while abdomino-
pelvic actinomycosis is thought to develop after disruption of
mucous membranes in a variety of conditions, the majority of
which include patients who have undergone previous surgery.7,8
For example, it has been reported following acute appendici-
tis, diverticulitis, and abdominal operations.3It is interesting to
speculate that inflammation of a diverticulum, with entry of the
organism via that route, might have been the precipitating event
in this patient, since diverticular disease was identified adjacent
to the colonic mass, in the resected specimen. An increase inci-
dence of abdomino-pelvic actinomycosis has recently been shown
to occur in patients with an intrauterine contraceptive device in
nomycosis may include low-grade pyrexia, vague abdominal pain,
nausea, vomiting and the presence of an abdominal mass or fistula.
Radiological studies have generally not been very useful.
Imaging with CT scans or ultrasound may identify the pres-
ence of a mass without distinctive diagnostic features. However,
it has been suggested that the presence of an infiltrative mass on
or without core biopsy of suspicious lesions.10
The differential diagnosis, in patients who present with an
abdominal mass includes: appendicitis, diverticulitis, inflamma-
tory bowel disease, tuberculosis and pelvic inflammatory disease.
A diagnosis of a malignant tumour is also frequently made. The
ileocaecal site is the most frequently affected in patients with
abdominal actinomycosis.3Involvement of the transverse colon by
the mass, in this case made a diagnosis of malignancy even more
The chronic suppurative infection that occurs in abdomino-
mass, multiple abscesses and a marked inflammatory reaction that
may involve the abdominal wall, occasionally with fistula forma-
tion. The diagnosis is confirmed by microbiological examination of
pus, sinus drainage, or tissue biopsy. Gram staining reveals the typ-
sulphur granules. Because of the scarcity of granules in the speci-
men, multiple sections may be required. The presence of sulphur
granules though important is not pathognomonic since other bac-
terial infections, e.g. those caused by nocardia, streptomyces, and
staphylococcus may be associated with this finding.9
Surgical treatment is usually required for the drainage of
tion or an abdominal mass. Preoperative diagnosis aided by
aspiration or biopsy of lesions may avoid surgical resection in
patients without significant surgical complications. Regardless,
antibiotic treatment will be required. The recommended antibiotic
of choice is Penicillin G (18–24 million units/day). Where peni-
cillin allergy exists, treatment with tetracycline, clindamycin, or
doxycycline has been reported. Prolonged treatment with amoxy-
In conclusion, abdominal actinomycosis is an uncommon
chronic suppurative disease caused by Actinomycosis israelii, which
results in infiltrative abdominal mass lesions, which are often
indistinguishable from malignancy. In the majority of cases, the
diagnosis is not suspected as was the case in this particular patient,
and is only confirmed by positive cultures of the organism and the
presence of sulphur granules in the resected specimen. Large doses
of the organism.
Conflicts of interest
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