Prepared by Robert L. Cirillo, Jr., MD of the Department of
Radiology, University of Wisconsin Hospitals and Clinics,
A 64-year-old female presented with a 2-week history of
intermittent episodes of abdominal pain and rectal bleeding. Past
medical history is remarkable for years of asymptomatic ulcerative
A colonoscopy was performed, followed by a double contrast barium
enema (figures 1 and 2).
Filiform polyposis of the colon
Double contrast barium enema showed numerous slender filling
defects in the colon, typical of filiform polyposis. Colonoscopy
with biopsies revealed multiple inflammatory polyps throughout the
colon with normal appearing intervening mucosa. Biopsy also showed
mild chronic mucosal inflammation and edema without significant
glandular distortion or fibrosis.
Filifform polyposis is a rare sequela of inflammatory bowel
disease, especially Crohn's disease and ulcerative colitis. The
term was originally described by Appelman et al1 and consisted of a
characteristic radiographic appearance of numerous slender,
finger-like or filiform defects in the colon with a normal haustral
pattern. These mucosal lesions are composed of submucosa covered by
normal or minimally inflamed mucosa. The surrounding mucosa may be
normal, although acute or chronic inflammatory changes may be
present. The filling defects have been described as vermiform,
worm-like, spaghetti-like, or as resembling the stalk of a polyp
without the head.2 The transverse colon and descending colon are
the most common location, although the polyps can be seen in any
portion of the large bowel with the exception of the rectum.1,3
There have also been reported cases in the stomach and, rarely, in
the small bowel.4 Filiform polyps of the colon may be
misinterpreted as unusual villous adenomas or small carcinomas on
colonoscopy. It is of particular importance to differentiate the
lesion from carcinoma in long-standing ulcerative colitis or
familial adenomatous polyposis. However, there is no known
association between filiform polyposis and the development of
The pathogenesis of filiform polyposis is uncertain, although it
has been speculated that a previous history of inflammatory disease
with long periods of quiescence is involved.
The polyps seem to proliferate between two adjacent inflamed,
ulcerated zones. The development of the polyps is comparable to the
reparative process and formation of inflammatory pseudopolyps seen
in ulcerative colitis. Pseudopolyps of ulcerative colitis consist
of islands of inflamed, edematous mucosa and granulation tissue
that layers between denuded and ulcerative areas; while filiform
polyps consist of a submucosa core with blood vessels and smooth
muscle fibers. The submucosa of filiform polyps is elevated and
pulled into the formation of a stalk due to the proliferating and
regenerative epithelium. Thus, filiform polyps are different from
the typical pseudopolyps of ulcerative colitis, since pseudopolyps
consist of regenerating mucosa that stands out only because the
surrounding mucosa is ulcerated. However, both filiform polyps and
pseudopolyps polyps are seen in the quiescent phase of ulcerative
colitis and Crohn's disease.
Filiform polyps usually appear as thin, straight filling defects
resembling the stalks of polyps without the heads. The polyps can
range in size from 1.5 to 3.0 cm in length and up to 0.5 cm in
diameter. The projections can occur as solitary polyps or as
diffuse polyposis distributed over large areas of the colonic
mucosa. In some cases, a radiating or branching pattern can be
identified, particularly at the tip of the polyps.
These lesions can be confused with unusual villous adenomas,
small carcinomas, or mucus threads on barium. The projections can
arborize and fuse at their tips and thus form mucosal bridges that
can trap fecal material and lead to the formation of a large
fecalith, which can cause obstruction. These obstructions have been
confused with carcinoma.
Bleeding can also be encountered in patients with filiform
polyposis. If identified, the bleeding is likely to originate from
the intervening inflamed mucosa rather than from the polyps
themselves, although the polyps do have a rich vascular component.
In most cases, when these polyps are identified, there is usually
no radiologic evidence of acute colitis and these polyps may be the
first due to the presence of inflammatory bowel disease.
Filiform polyposis is a rare form of pseudopolyposis associated
with ulcerative colitis, Crohn's disease, and granulomatous disease
that is formed by a nonspecific mucosal and submucosal reaction to
previous severe inflammation.
It is important to recognize that filiform polyposis is a benign,
radiographically characteristic form of inflammatory polyps that
should not be mistaken for a neoplastic familial polyposis
syndrome. Filiform polyposis alone is not an indication for
surgical resection, but complications, such as acute massive
or intestinal obstruction,
may necessitate surgical intervention.
1. Appelman HD, Threatt BA, Ernst C, et al:
Filiform polyposis of the colon: An unusual sequela of ulcerative
colitis. Am J Clin Path 62:145-146, 1974. Abstract.
2. Zegel HG, Laufer I:
Filiform polyposis. Radiology 127:615-519, 1978.
3. Spark RP:
Filiform polyposis of the colon. First report in a case of
transmural colitis. Digestive Dis 21:809-814, 1976.
4. Bray JF:
Filiform polyposis of the small bowel in Crohn's disease.
Gastrointest Radiol 8:155-156, 1983.
5. Renison DM, Forouhar FA, Levine JB, Breiter JR:
Filiform polyposis of the colon presenting as massive hemorrhage:
An uncommon complication of Crohn's disease. Am J of Gastro
6. Antonow DR, Gebhard RL, Dykosld RK, Sumner HW:
Filiform polyposis in Crohn's colitis mimicking toxic megacolon.
Dig Dis Sci 26:1051-1055, 1981.
7. Goldenberg B, Mori K, Friedman IH, et al:
Fused inflammatory polyps simulating carcinoma and ulcerative
colitis. Am J Gastroenterol 73:441-444, 1980.