Abstract
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INTRODUCTION
Medium-vessel vasculitis involving the visceral circulation is rare and most commonly attributed to systemic vasculitides such as polyarteritis nodosa, or in older patients, giant cell arteritis. Its imaging hallmark –– circumferential mural thickening with luminal narrowing and perivascular fat stranding (“perivascular cuffing”) –– is nonspecific and may also result from perineural or perivascular tumor spread, most classically from pancreatic ductal adenocarcinoma (PDAC). This diagnostic overlap can lead to prolonged misclassification of an underlying malignancy as a primary inflammatory vasculopathy.
CASE PRESENTATION
A 63-year-old Filipino woman with a two-year history of intermittent abdominal pain, post-prandial vomiting and loose watery stools was initially diagnosed with superior mesenteric artery (SMA) vasculitis after CT aortography demonstrated circumferential SMA wall thickening with luminal narrowing, subsequently corroborated by duplex ultrasound and FDG-avid PET-CT findings. Negative anti-neutrophil cytoplasmic antibody (ANCA) serologies and normal inflammatory markers precluded corticosteroids initiation, and the patient was co-managed by Rheumatology and Thoracic and Cardiovascular Surgery (TCVS) for nearly a year. She was later admitted for worsening vomiting and constipation wherein a repeat CT imaging was done revealing a peripancreatic/ retroperitoneal mass with desmoplastic reaction, hepatic and osseous metastases, and progressive encasement of the celiac trunk, SMA, and left renal artery. Markedly elevated CEA with only mild elevated CA 19-9 raised suspicion for malignancy. Biopsies of the hepatic and retroperitoneal masses confirmed adenocarcinoma, with immunohistochemistry (CK7+, CK19+, SMAD4+, CK20-, CDX2-, Glypican-3 -, Arginase-1 -) supporting a pancreatobiliary origin. The SMA findings were retrospectively reclassified as malignancy-associated periarterial involvement rather than a primary vasculitis.
CONCLUSION
Pancreatic adenocarcinoma should be considered in the differential diagnosis of isolated visceral arterial wall thickening, even in the absence of discrete pancreatic mass on initial imaging. Diagnostic anchoring toward vasculitis
–– particularly when serologies are negative –– may delay oncologic diagnosis; tissue sampling from the safest accessible lesion should be prioritized before empiric immunosuppression.
Keywords: superior mesenteric artery vasculitis, pancreatic ductal adenocarcinoma, perivascular cuffing, polyarteritis nodosa
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