AJR 2002; 179:536-537
© American Roentgen Ray Society
Localized Amyloidosis Mimicking Carcinoma of the Colon
Jeon-Hor Chen,
Shia-Jou Lai,
Po-Pang Tsai and
Yong-Fang Chen
China Medical College Hospital Taichung 404, Taiwan
Amyloidosis is a rare disease caused by deposits of rigid nonbranching
fibrils of various proteins. Although amyloidosis can occur in virtually any
organ system in the body, including the gastrointestinal tract, localized
amyloidosis in the gut is rare
[1,2,3].
Recently, we encountered a patient with amyloidosis in the transverse colon
that mimicked carcinoma of the colon.
A 52-year-old man presented at our hospital because of a periumbilical
pain, bloody stool, and weight loss of 5 kg in recent months. Results of
laboratory tests were normal except that occult blood was found in the stool.
Colonoscopy performed in our outpatient department revealed a marked narrowing
of the lumen of the transverse colon with multiple polypoid lesions. A small
ulceration was also found (Fig.
2A). Because carcinoma of the colon was suspected, a biopsy and a
barium enema were performed. Findings from the barium enema revealed an
annular lesion with mildly disrupted mucosa in the transverse colon, which
suggested malignancy (Fig. 2B). Two days later, the patient underwent rightsided hemicolectomy with an
ileocolic anastomosis to relieve intestinal obstruction and severe abdominal
pain. Eight lymph nodes in the pericolic area were also resected.
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Fig. 2A. —52-year-old man with localized amyloidosis in transverse
colon. Colofibroscopic image shows almost total obstruction of lumen of colon.
Multiple polypoid lesions and small ulceration are clearly visible.
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Fig. 2B. —52-year-old man with localized amyloidosis in transverse
colon. Image from barium enema study shows annular lesion in transverse colon
mimicking carcinoma of colon. Note markedly narrowed lumen and disrupted
mucosa.
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At gross examination, the specimen from the colon was observed to have
smooth serosa with no evidence of invasion. An ulcerative, soft-elastic mass
measuring 5 x 4 cm was found. Microscopically, the mass was revealed to
be an amorphous, slightly eosinophilic substance deposited on the submucosa
and lamina propria (Fig. 2C). Ulceration in the mucosa was seen, as well as perivascular deposits of the
eosinophilic material. A sample of the deposited material was lightly stained
when treated with periodic acid—Schiff stain and had an apple-green
birefringence when treated with Congo red stain and viewed with a polarizing
lens (Fig. 2D). Amyloidosis was
diagnosed. No amyloid deposits were found on the omentum and ileum.
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Fig. 2C. —52-year-old man with localized amyloidosis in transverse
colon. Photomicrograph of histopathologic specimen of amyloid deposit shows
amorphous deposits in lamina propria and around blood vessels. (H and E,
x100)
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Fig. 2D. —52-year-old man with localized amyloidosis in transverse
colon. Photomicrograph of histopathologic specimen of amyloid deposit.
Specimen has apple-green birefringence when viewed under polarizing lens.
(Congo red, x200)
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One week after surgery, the patient experienced severe abdominal pain, and
an anastomotic leak was suspected. The leak was repaired, and ileostomy was
performed. IV hyperalimentation was given for nutritional support.
Three months after the second operation, the patient developed stenosis of
the stoma at the site of the ileostomy. He was readmitted to our hospital,
where dilatation of the stoma and multiple biopsies in the stoma and ileum
were performed. Colonscopy and panendoscopy of the upper gastrointestinal
tract were performed, in addition to multiple biopsies in the stomach, rectum,
sigmoid colon, descending colon, and transverse colon. None of the biopsy
specimens revealed any evidence of amyloid deposits. Extensive laboratory
investigations, physical examinations, and history taking provided no evidence
of disease, such as myeloma or collagen disease, that could have led to the
development of secondary amyloidosis. Therefore, the diagnosis was consistent
with isolated amyloidosis of the transverse colon.
Gastrointestinal infiltration by amyloid material is common and has been
reported in 70% of cases of primary amyloidosis and in 55% of cases of
secondary amyloidosis [1]. The
walls of the submucosal blood vessels are the most frequent sites of amyloid
deposits, and diffuse deposits may result in impaired motility, malabsorption,
and ulceration because of the related ischemia
[2]. Clinical manifestations of
gastrointestinal amyloidosis may mimic those of other diseases, such as
inflammatory bowel disease, ischemic colitis, and intestinal perforation
[2]. An isolated involvement of
the colorectum without systemic deposition, albeit rare, has been previously
reported, and these lesions frequently simulate a submucosal tumor or
carcinoma [2,
3]. Macroscopically, it is
difficult to distinguish localized amyloidosis from a neoplasm. An endoscopic
examination with biopsy is the most reliable diagnostic tool available.
Microscopically, amyloid material appears as an eosinophilic amorphous
substance when stained with H and E. It is stained orange by Congo red stain
and is seen as yellowish gold deposits when viewed with a polarizing
microscope [4].
Patients with amyloidosis have been treated by IV hyperalimentation; by
administration of corticosteroids, immunosuppressive agents, dimethyl
sulfoxide, or cochicine; or by surgery. Because no specific therapy is
available, it is difficult to select the most effective therapeutic regimen.
Effective preventive treatment against localized amyloidosis deposits in the
gastrointestinal tract is also uncertain. The affected mucosa is fragile and
tends to bleed, which can cause suture failure; therefore, it has been
suggested that surgery should be limited to extreme emergencies, such as in
patients with massive bleeding, a perforation, or an obstruction
[4]. In our patient, a
right-sided hemicolectomy was performed because of an acute colonic
obstruction. Leakage of the anastomosis during the immediate postoperative
period might have been caused by the fragility of the mucosa.
References
- Dey C, Duvoisin B. CT findings in primary amyloidosis of the colon.
J Comput Assist Tomogr
1989;13:1094
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- Hirata K, Sasaguri T, Kunoh M, Shibao K, Nagata N, Itoh H. Solitary
"amyloid ulcer" localized in the sigmoid colon without evidence of
systemic amyloidosis. Am J Gastroenterol
1997;92:356
-357[Medline]
- Watanabe T, Kato K, Sugitani M, et al. A case of solitary
amyloidosis localized within the transverse colon presenting as a submucosal
tumor. Gastrointest Endosc
1999;49:644
-647[Medline]
- Matsui H, Kato T, Inoue G, Onji M. Amyloidosis localized in the
sigmoid colon. J Gastroenterol
1996;31:607
-611[Medline]
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