DOI:10.2214/AJR.05.0108
AJR 2006; 186:586-587
© American Roentgen Ray Society
Unusual Manifestation of Small-Vessel Vasculitis
Frank W. Roemer,
Johannes Demharter,
Joachim Zentner and
Wolfgang Buecklein
Klinikum Augsburg Augsburg, Germany
A 54-year-old man was referred to the surgical department of our
institution with a 4-week history of lower abdominal and inguinal pain
accompanied by fever, fatigue, and nocturnal sweating. Physical examination at
admission was unremarkable. CT and MRI performed shortly after referral showed
diffuse edema of the pelvic mesenterium and subcutaneous tissues of the lower
abdominal wall (Figs. 2A,
2B, and
2C). After IV contrast
administration, diffuse enhancement was shown for the respective body
regions.
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Fig. 2A —54-year-old man with microscopic polyangiitis of pelvic region.
T1-weighted fat-suppressed MR image after IV contrast administration. Diffuse
contrast enhancement is shown in pelvic mesenterium and lower abdominal wall.
No enhancement within muscles and dorsal subcutaneous tissues is observed.
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Fig. 2B —54-year-old man with microscopic polyangiitis of pelvic region.
Unenhanced T1-weighted MR image without fat suppression shows hypointense
pelvic edema and thickened sigmoid wall (arrowheads).
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Fig. 2C —54-year-old man with microscopic polyangiitis of pelvic region.
Corresponding T2-weighted fat-suppressed image depicts superiorly diffuse
pericolic (black arrows) and subcutaneous (white arrows)
hyperintense edematous alterations.
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Furthermore, MRI and sonography depicted a thickened sigmoid wall of up to
5 mm without additional findings of possible perforation
(Fig. 2B). With a provisional
diagnosis of diverticulitis, antibiotic treatment was started without
improvement of symptoms during the following week. Finally, a biopsy of the
edematous subcutaneous lower abdominal wall was performed. Histology showed
nongranulomatous vasculitis of the arterioles and venules with inflammatory
infiltrates of lymphocytes, granulocytes, histiocytes, and plasma cells
sparing the larger veins and arteries (Fig.
2D). In accordance with the Chapel Hill classification,
microscopic polyangiitis (MPA) was diagnosed
[1].
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Fig. 2D —54-year-old man with microscopic polyangiitis of pelvic region.
Histology illustrates subtotal obliteration of vessel lumen
(arrowheads). Perivascular mixed lymphocytic and granulocytic
inflammatory infiltration is shown. Edematous changes and partial necrosis of
medial layer (arrows) are depicted. (H and E, x200)
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In addition, all performed examinations for surrogate parameters indicative
of vasculitis showed unremarkable findings. These included evaluation of the
lungs, kidneys, brain and supraaortic arteries, and eyes as well as antibody
screening and further laboratory tests. Treatment with a combination of
steroids and cyclophosphamide was initiated. Clinical symptoms and radiologic
findings soon resolved. Follow-up MRI after 4 weeks of treatment showed
normalization of the edematous tissues and no pathologic contrast
enhancement.
MPA has the same spectrum of manifestations of small-vessel vasculitis as
Wegener's granulomatosis but does not include granulomatous inflammation
[1]. Approximately 90% of
patients with MPA have glomerulonephritis, the most common form of
pulmonary-renal syndrome. This disease can be accompanied by a variety of
further organ involvement [2].
According to the Chapel Hill nomenclature, the diagnosis of MPA requires
evidence of necrotizing small-vessel vasculitis with few or no immune
deposits, not restricted to the skin, and without granulomatous inflammation
of the respiratory system
[1].
The findings in our patient supported the diagnosis of MPA. More than 80%
of patients with MPA have antineutrophil cytoplasmic antibodies (ANCA), but a
minority of patients with typical clinical and pathologic findings of the
disease are ANCA-negative [3],
as was the case in our patient. Pelvic fluid collections in panarteritis
nodosa were reported earlier in the literature
[4], but to our knowledge the
radiologic features of isolated MPA confined to the pelvic region and
abdominal wall have not been described before.
The radiologic differential diagnosis in our patient includes other
inflammatory conditions such as colitis with pericolic edema. Peritoneal
carcinomatosis has to be considered as well. The absence of nodular lesions,
missing ascites, and the confinement to the pelvis and involvement of the
abdominal wall made this differential diagnosis highly unlikely.
Because early diagnosis and treatment improve outcomes in these patients
dramatically, this case stresses the importance of including small-vessel
vasculitis in the radiologic differential diagnosis of edematous alterations
confined to distinct body regions.
References
- Jennette JC, Falk RJ, Andrassy K, et al. Nomenclature of systemic
vasculitides: proposal of an international consensus conference.
Arthritis Rheum 1994;37
: 187-192[Medline]
- Niles JL, Bottinger EP, Saurina GR, et al. The syndrome of lung
hemorrhage and nephritis is usually an ANCA-associated condition.
Arch Intern Med 1996;156
: 440-445[Abstract/Free Full Text]
- Kallenberg CG, Brouwer E, Weening JJ, Tervaert JW. Anti-neutrophil
cytoplasmic antibodies: current diagnostic and pathophysiological potential.
Kidney Int 1994;46
: 1-15[Medline]
- Jaques PF, Parker LA, Mauro MA. Fulminant systemic necrotizing
arteritis: CT findings. J Comput Assist Tomogr1988; 12:104
-108[Medline]
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