DOI:10.2214/AJR.05.0638
AJR 2006; 186:1193-1195
© American Roentgen Ray Society
Omental and Peritoneal Involvement in Systemic Amyloidosis: CT with Pathologic Correlation
Marius Horger,
Monika Vogel,
Harald Brodoefel,
Heiko Schimmel and
Claus Claussen
Eberhard-Karls-University Tuebingen, Germany 72076
Systemic amyloidosis is characterized by widespread extracellular
deposition of amyloid in multiple organs and tissues. Omental amyloidosis and
peritoneal amyloidosis are extremely rare manifestations of this disease that
are usually not considered in the differential diagnosis of peritoneal and
omental infiltrations.
A 69-year-old man was referred to our institution with symptomatic
bradycardia and progressive development of dyspnea. Ten months earlier, he was
diagnosed with monoclonal IgG lambda gammopathy of unknown significance.
Skeletal radiography at that time could not disclose any osteolysis suggestive
of multiple myeloma. Clinical examination revealed large amounts of ascites
that were drained repeatedly for therapeutic and diagnostic reasons.
Analysis of ascites samples, however, was without definite results. A
malignant process could not be clearly excluded. Blood analysis revealed
elevated liver enzymes: glutamic-oxaloacetic transaminase, 64 U/L (reference
value, < 35 U/L); glutamic-pyruvic transaminase, 57 U/L (reference, < 45
U/L); alkaline phosphatase, 188 U/L (reference, < 130 U/L); and
-glutamyl transpeptidase, 209 U/L (reference, < 37 U/L). Creatinine
was 1.5 mg/dL (reference, < 1.1 mg/dL) and urea was 96 mg/dL (reference,
12-46 mg/dL), showing evidence of moderate impairment for renal function. The
other values, especially for calcium and hemoglobin, were normal.
Abdominal CT performed with oral water application (hydro-CT) and IV iodine
contrast material application of 120 mL of iopromide (Ultravist 370, Schering)
showed slight liver enlargement with homogeneous density on unenhanced and
enhanced series, and abundant ascites. The density of ascites was 8-10 H.
Increased soft-tissue infiltration of the greater omentum with a nodular
pattern was found (Fig. 2A).
The thickened omentum showed low density (15-20 H) on unenhanced CT without
significant enhancement 50 sec after IV administration of contrast material
(Fig. 2B). No calcifications
were present in the greater omentum and in the few slightly enlarged
mesenteric lymph nodes. The bowel wall was well demarcated and presented with
a normal thickness of less than 4 mm after IV administration of 40 mg of the
antispasmodic drug butylscopolaminium bromide (Buscopan, Boehringer Ingelheim
Pharma). The other abdominal viscera revealed no abnormalities on CT.
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Fig. 2C —69-year-old man with systemic amyloidosis. Photomicrograph of
histopathologic specimen of greater omentum was obtained after Congo red
staining and apple-green birefringence under polarized light. Image shows
extensive vascular and connective tissue amyloid deposits infiltrating
vascular sheaths and connective tissue of greater omentum. (x200)
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During colonoscopy performed for further clarification, the patient
developed an acute circulatory collapse and died. Autopsy revealed evidence of
generalized amyloidosis. Extensive amyloid deposits were found in the entire
gastrointestinal tract infiltrating the circular muscle layer, the tela
submucosa of the small and large intestine, and the vascular sheaths and
connective tissue of the greater omentum
(Fig. 2C), as well as the
spleen, kidneys, thyroid gland, and myocardium. Bone marrow immunochemistry
showed 30-40% of hematopoietic cells to be IgG lambda-positive plasma
cells.
Diffuse omental involvement in systemic amyloidosis is uncommon
[1]. Most retroperitoneal fat
infiltrations due to amyloid deposition are encountered in either a nodular or
a diffuse pattern. The nodular form corresponds to enlarged lymph nodes; in
the diffuse form, amyloid is distributed diffusely throughout the
retroperitoneal or omental fat. Secondary calcification of amyloid deposits is
suggestive of amyloidosis, irrespective of the involved site
[2]. Twenty percent of patients
with amyloidosis present initially with ascites because of cardiac, hepatic,
and renal failure mostly associated with pleural effusion and signs of cardiac
insufficiency. Although gastrointestinal manifestations by amyloid material
are common and have been reported in 70% of cases of primary amyloidosis and
in 55% of cases of secondary amyloidosis, accompanying involvement of the
greater omentum is extremely rare
[3,
4].
Mallet et al. [5] reported
in 1985 the first case of amyloid peritoneal deposition presenting clinically
with ascites. At the same time, Weinrauch et al.
[1] described a case of
peritoneal infiltration by amyloid restricted to the serosa without bowel
involvement. Other authors also wrote that the mesenteries and omentum, like
adipose tissue elsewhere, may be extensively involved in this disease
[3]. Nevertheless,
differentiation from other infectious or tumoral diseases involving the
peritoneum and greater omentum is difficult, and is possible only in
correlation with clinical and laboratory data, especially in patients in whom
systemic amyloidosis has not yet been diagnosed. Therefore, biopsy is
generally needed to exclude malignancy.
In comparison with patients with carcinomatosis, lymphomatosis,
sarcomatosis, or even acute inflammation, enhancement of amyloid deposits in
the omentum and peritoneum is poor or absent. Characteristically, the amyloid
deposits show apple-green birefringence when stained with Congo red and viewed
under polarized light.
In this case, diffuse involvement of the greater omentum presented without
calcification or radiologic evidence of involvement of the gastrointestinal
tract, such as focal or diffuse gastric wall or bowel wall thickening or
dilatation owing to adynamic ileus or ulcerations, which, to our knowledge,
has not yet been reported in the radiology literature. Even the involvement of
the liver, spleen, and kidneys was not apparent. Thus, correlation between CT
and histologic data was poor and correct diagnosis remained difficult.
However, the awareness of possible omental and peritoneum involvement in
systemic amyloidosis should help in the differential diagnosis in patients
with monoclonal gammopathy of unknown origin.
References
- Weinrauch LA, Desautels RE, Christlieb AR, et al. Amyloid
deposition in serosal membranes: its occurrence with cardiac tamponade,
bilateral ureteral obstruction, and gastrointestinal bleeding. Arch
Intern Med 1984; 144:630
-632[Abstract]
- Coumbaras M, Chopier J, Massiani M-A, Antoine M, Boudghene F, Bazot
M. Diffuse mesenteric and omental infiltration by amyloidosis with omental
calcification mimicking abdominal carcinomatosis. Clin
Radiol 2001; 56:674
-676[CrossRef][Medline]
- Berardi RS, Malette WG. Focal amyloidosis of small bowel mesentery.
Int Surg 1973; 58:491
-494[Medline]
- Allen HA 3rd, Vick CW, Messmer JM, et al. Diffuse mesenteric
amyloidosis: CT, sonographic and pathologic findings. J Comput
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-198[Medline]
- Mallet H, Humbert P, Dupond JL, Des Floris RL. Amyloid deposition
in serosal membranes. Arch Intern Med1985; 145:2264[Medline]
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