DOI:10.2214/AJR.05.0024
AJR 2006; 186:1113-1115
© American Roentgen Ray Society
Venous Malformations Mimicking Multiple Mucosal Polyps on Screening CT Colonography
Andrew D. Lee1,
Perry J. Pickhardt1,
Deepak V. Gopal2 and
Andrew J. Taylor1
1 Department of Radiology, University of Wisconsin Medical School, E3/311
Clinical Science Center, 600 Highland Ave., Madison, WI 53792-3252.
2 Section of Gastroenterology & Hepatology, University of Wisconsin Medical
School, Madison, WI 53792-3252.
Received January 6, 2005;
accepted after revision February 10, 2005.
Address correspondence to P. J. Pickhardt.
Keywords: colon • colonography • colonoscopy • CT • screening • venous malformations
Introduction
Screening for colorectal polyps by CT colonography recently has been shown
to be effective when state-of-the-art technique is applied
[1]. The primary target lesion
for colorectal screening is the neoplastic polyp, more specifically the
advanced adenoma, because its detection and removal are believed to interrupt
the slow progression to cancer. The finding of a polypoid lesion on CT
colonography, however, has a rather broad differential diagnosis
[2]. We recently encountered
another cause for a polypoid lesion on CT colonography that, to our knowledge,
has not been described previously: multiple venous malformations or vascular
blebs in an asymptomatic patient with quiescent and previously undiagnosed
blue rubber bleb nevus syndrome.
Case Report
A 64-year-old asymptomatic man was referred to our CT colonography program
for routine colorectal screening. He underwent our standard CT colonography
preparation the day before the examination, consisting of oral sodium
phosphate (45 mL), 2% barium sulfate suspension (250 mL), and water-soluble
iodinated contrast material (diatrizoate, 60 mL). Colonic distention was
achieved by automated CO2 delivery (PROTOCO2L, E-Z-EM).
Supine and prone CT images were obtained on MDCT (LightSpeed Ultra, GE
Healthcare) using 16 x 1.25-mm detector configuration, 1-mm
reconstruction interval, 120 kVp, and 50 mAs. The CT colonography study was
interpreted using commercial software (V3D Colon, Viatronix) by a
gastrointestinal radiologist with extensive experience. A biphasic
interpretive approach is used at our institution, consisting of primary 3D
polyp detection combined with secondary 2D detection and confirmation of
suspicious 3D findings.
CT colonography examination revealed multiple small- to medium-sized
polypoid lesions within the colon, measuring up to 9 mm (Figs.
1A,
1B, and
1C). All of the lesions were
composed of uniform soft-tissue attenuation on the noncontrast 2D images and
were predominantly concentrated in the transverse colon. A presumptive
diagnosis of multiple mucosal-based polyps was made. The patient was referred
to same-day optical colonoscopy because the criterion of three or more
medium-sized polyps (6-9 mm) was met (our other criterion for referral is any
polyp 10 mm or greater). We do not report diminutive lesions measuring 5 mm or
less at CT colonography.
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Fig. 1A —64-year-old man referred for initial colorectal screening.
Endoluminal 3D (A and B) and coronal 2D (C) images from
screening CT colonography show multiple subcentimeter polypoid lesion
(arrows). B and C show the same lesion on 3D and 2D,
respectively. Lesions were all of soft-tissue attenuation and measured up to 9
mm.
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Fig. 1B —64-year-old man referred for initial colorectal screening.
Endoluminal 3D (A and B) and coronal 2D (C) images from
screening CT colonography show multiple subcentimeter polypoid lesion
(arrows). B and C show the same lesion on 3D and 2D,
respectively. Lesions were all of soft-tissue attenuation and measured up to 9
mm.
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Fig. 1C —64-year-old man referred for initial colorectal screening.
Endoluminal 3D (A and B) and coronal 2D (C) images from
screening CT colonography show multiple subcentimeter polypoid lesion
(arrows). B and C show the same lesion on 3D and 2D,
respectively. Lesions were all of soft-tissue attenuation and measured up to 9
mm.
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Multiple polypoid lesions measuring up to 9 mm and located within matching
colonic segments were confirmed at optical colonoscopy (PENTAX EC-3831L,
PENTAX Medical Co.) performed several hours after CT colonography. The
lesions, however, were not mucosal polyps, but instead were well-defined
raised submucosal vascular blebs with a distinctive bluish hue (Figs.
1D and
1E). Biopsy was not performed
because of the vascular nature of the lesions, combined with the fact that the
endoscopic appearance was characteristic and diagnostic.
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Fig. 1D —64-year-old man referred for initial colorectal screening. Digital
photographs from optical colonoscopy later that same day show multiple
discrete, raised submucosal lesions with distinctive bluish hue. Endoscopic
appearance is characteristic of vascular blebs.
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Fig. 1E —64-year-old man referred for initial colorectal screening. Digital
photographs from optical colonoscopy later that same day show multiple
discrete, raised submucosal lesions with distinctive bluish hue. Endoscopic
appearance is characteristic of vascular blebs.
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On further questioning of the patient, he noted the lifelong presence of
multiple raised cutaneous lesions consistent with small venous malformations
or hemangiomas. He denied any history of gastrointestinal bleeding, anemia, or
other significant disease. The patient had undergone a negative flexible
sigmoidoscopy 5 years earlier but had not had any other previous
gastroenterologic, radiologic, or dermatologic workup. The cutaneous and
gastrointestinal findings were thought to be compatible with a mild phenotypic
and sporadic form of blue rubber bleb nevus syndrome.
Discussion
CT colonography has been shown to be an accurate screening tool for
detection of colorectal polyps when advanced 3D techniques and contrast
tagging are emphasized [1].
Advanced adenomas are the primary target lesion for colorectal cancer
screening, but a wide array of additional entities can present as a polypoid
lesion on CT colonography [2].
In addition to mucosal-based neoplasms, other broad categories include
nonneoplastic mucosal lesions, submucosal lesions, impression from extrinsic
lesions, and a variety of CT colonography pitfalls and artifacts. Vascular
lesions, such as the venous malformations or vascular blebs shown in the
current case, represent a rare submucosal cause of polypoid lesions on CT
colonography and, to our knowledge, have not been reported previously. In
general, mucosal versus submucosal origin of small focal lesions is sometimes
a difficult distinction on CT colonography.
The colonic venous malformations in this case had a sessile morphology and
homogeneous soft-tissue attenuation, making them indistinguishable from
mucosal polyps at CT colonography. We do not routinely administer IV contrast
material for screening CT colonography examinations, but given the vascular
nature of these lesions, IV contrast material may have shown prominent
enhancement in this particular case. However, because mucosal polyps also show
enhancement after IV contrast, the distinction would be only one of degree
[3].
The blue rubber bleb nevus syndrome, first described by Gascoyen in 1860
and later named by Bean [4] in
1958, is a rare condition characterized by multiple venous malformations or
hemangiomas involving various organ systems. Both an autosomal dominant
inheritance pattern and sporadic cases have been observed. Typically, multiple
discrete venous lesions manifest primarily in the skin and the
gastrointestinal tract, with the small bowel more commonly affected than the
large bowel. However, other organ systems may be involved, including but not
limited to the central nervous, musculoskeletal, genitourinary, and endocrine
systems [5].
Cutaneous lesions usually are present at birth and tend to grow in number
and size with age. These rubbery skin lesions are blanching macules with a
blue color and may be painful. These typically are located in the limbs,
trunk, and palmar aspect of the hands and feet. Gastrointestinal lesions in
blue rubber bleb nevus syndrome have a distinctive appearance at optical
endoscopy [6]. Histologically,
they appear as engorged dilated capillaries within the submucosa and lamina
propria. Gastrointestinal involvement with blue rubber bleb nevus syndrome
most commonly manifests with chronic iron deficiency anemia resulting from
gastrointestinal bleeding. Patients rarely may present with small-bowel
obstruction from intussusception
[7]. The clinical significance
of asymptomatic lesion detection as seen in the current case is unknown.
In conclusion, we report a rare cause of polypoid colonic lesions
indistinguishable from mucosal-based polyps on CT colonography. Subsequent
endoscopy, although not therapeutic as is typically the case, provided the
specific diagnosis without the need for further workup.
References
- Pickhardt PJ, Choi JR, Hwang I, et al. CT virtual colonoscopy to
screen for colorectal neoplasia in asymptomatic adults. N Engl J
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- Pickhardt PJ. Differential diagnosis of polypoid lesions seen at CT
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- Bean WB. Blue rubber bleb naevi of the skin and gastrointestinal
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Introduction
Case Report
