Unsuspected Active Ulcerative Colitis in a Patient With Dermatomyositis: A Rare Association Detected on 18F-FDG PET/CT During the Search for an Occult Malignancy

Dermatomyositis is an inflammatory myopathy with the characteristic features of skin rash and myopathy. We here present a known case of dermatomyositis evaluated with 18F-FDG PET/CT for the presence of any occult malignancy. The scan was negative for the presence of any malignancy. However, it revealed multiple intensely FDG avid colonic strictures that were later proven on colonoscopic biopsy to be ulcerative colitis. Also, a well-known association of bilateral sacroilitis was simultaneously demonstrated on the scan. The present case demonstrates that 18F-FDG PET/CT imaging can serve as a one-stop shop imaging modality in dermatomyositis by facilitating detection of occult primary if any and by providing insight into other rare systemic associations.